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1 NATS to the Su A upport irpor rts Commis ssion Support to the Assessment of Potential Short Term Measures Issue 1 25 November 2013 Prepared by Steve Pybus, Stuart Price, Nick Stevens NATS Protected

2 2 NATS Support to the Airports Commission NATS Support to the Airports Commission Prepared by: Steve Pybus, Stuart Price, Nick Stevens Approved by: David Curtis Version November 2013

3 NATS Support to the Airports Commission 3 NATS Support to the Airports Commission Support to the Assessment of Potential Short Term Measures This briefing note brings together into a single document the material provided to the Airports Commission Secretariat to assist its review of the various proposals submitted to provide potential measures to identify Short Term measures to increase airport capacity and resilience in south-east England. The following aspects of input that have been provided are now collated in this submission: Queue Management Time Based Separation Low Visibility Procedures Mixed Mode Point Merge Displaced Thresholds Steeper Approaches Creation of a known Surveillance Environment Civil/Military Airspace Optimisation Heathrow SIDs Matters of Clarification on Queries Raised on Some of the Above Concepts Northolt Westerly Preference Mixed Mode for Resilience Advanced Navigation Capabilities and SIDs/STARs Project Milestones Multiple Arrival Routes for Respite A summary paper that summarised many aspect of the above input titled Evolving Air Traffic Operations: A Look into the future. The content of each of these aspects of potential future operations is explained in greater detail to provide the context in which these have been developed.

4 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Consider and advise what can be shared in respect of NATS work on Arrival Queue Management particularly about the projected impacts. Context Congestion is the most visible consequence of operational inefficiency at an airport. Even the smallest delays in the system can have a dramatic knock-on effect, leading to departure delays, missed slots and ultimately cancelled flights. Aside from frustrated passengers, congestion also creates environment problems, with increased emissions; unnecessary cost, with increased fuel consumption and possible cancellation of flights; and, adverse publicity for the airport, its ANSP and associated businesses. By 2020, with better scheduling available within the industry, accurate data and integrated runway management tools, NATS will optimise the use of runways and airspace through strategic and/or tactical intervention at the most efficient points of an intended or active flight; effective Queue Management is the key to achieving this aim. The primary goals of NATS Queue Management programme are to: Optimise runway utilisation for single airports and TMA airport groups. Optimising available runway capacity is at the heart of NATS Strategy and is of particular importance given the lack of plans to build additional runways in the South East of England; Eliminate stack holding in terminal airspace. If it is possible to do so, the elimination of stack holding in terminal airspace would improve safety and environmental performance whilst increasing the availability of airspace for Continuous Climb and Descent Operations; and, Enable free-flow departures for terminal airports. At a simple level, all airfields generating traffic operating under Instrument Flight Rules (as opposed to operating visually) should be electronically linked into the network; and should provide Departure Planning Information (or equivalent message) to the network. This will apply to any airfields within the AMAN metering horizon which are feeding traffic into an arrival stream. Whilst the departure and arrival elements the operators agree to fly within the TMA will have to be aligned with the demands of the airspace and synchronisation activity, operator business demands require a high degree of flexibility, meaning the ATC tools must have the ability to respond quickly to evolving operational situations. Queue Management covers all aspects related to improve arrival/departure management and sequence building in en-route and TMA environments in order to achieve an optimum traffic sequence resulting in significantly less need for ATC tactical intervention. As a consequence flights are able to fly closer to their optimum trajectories bringing benefits across Predictability, Efficiency, Safety, Capacity, and Environment. Feasibility Queue Management exists to reduce (and, aspirationally, eliminate) the need for queuing with resultant adverse impact on airline operations when demand exceeds capacity, which predominantly occurs during the preparation of the landing phase of flight when airport landing capacity cannot support imminent demand. Whilst the throughput of serial process system can be maximised by absorbing demand by queuing 1, in air traffic operations this results either airborne or ground holding, with varying primary (fuel and delay) impacts and secondary (scheduling) impacts. 1 For example, the Heathrow schedule is designed not to exceed 10 minutes average airborne holding.

5 NATS Queue Management programme comprises the coordinated development of a set of related investments to deliver operational improvements in this area to cover the various phases of flight that comprise the arrival and departure service delivery chain. The concept is wider than just Arrival Queue Management: NATS investments seek to deliver an holistic approach to arrival/departure service delivery so that a more balanced type of operation is provided without the need to hold/queue (and therefore penalise) either the arriving or departing traffic flows. Specifically, the Queue Management programme will deliver new or enhanced capabilities including the use of Time Based Separation (TBS) to support Heathrow and Gatwick arrivals, Departure Management (DMAN), Arrival Management (AMAN) and Time Based Flow Management (which uses extended AMAN techniques). Furthermore, other investments, outwith the QM Programme, also seek to deliver improvements in this field through revised airspace and route networks that (by design) reduce or avoid where possible the need for downstream queuing through the more predictable presentation of traffic, supported by concepts that aim to deliver for efficient queuing if required through linear holding and Point Merge concepts. The following activities are financed and currently in progress: Development of the extended AMAN horizon and improvement in AMAN system accuracy; New procedures whereby controllers reduce aircraft speed in the descent in order to reduce average stack holding by an anticipated 2 minutes at Heathrow; and, In co-operation with Eurocontrol Maastricht, DSNA Reims and IAA Shannon, the reduction of aircraft cruise speed from 350 miles out in order to save an anticipated further 2 minutes of stack holding on average at Heathrow. Benefits Effective QM will reduce the amount of time aircraft are kept in holding stacks, estimated to be worth 2m pa in avoided fuel costs. The benefits will be provided by better matching airport capacity with demand, with greater adherence to arrival times, better scheduling and Airport CDM seeking to better balance capacity & demand, supported by linear holding (i.e. time absorption via speed control) and Point Merge concepts. The reduction in the need for stack holding also improves safety by reducing the risks inherent in stacking operations due to the opportunity for level busts 2. Such outcomes will also increase the capacity within the London TMA; initial estimates indicate that between a further 5% - 10% capacity can be secured from the emerging LAMP airspace designs through more effective QM concepts and techniques. It should be noted that the benefits set out in this briefing note should not be double-counted with those that have, or mat in the future, be estimated and stated for those projects included in the QM programme. Strategic Intents It has been recognised that the airport scheduling process and the lack of adherence to schedule at constrained airports contributes to a reduction in overall efficiency. Currently the QM programme is engaged with airline operators and the CAA through the Future Airspace Strategy initiative in order to progress this issue. With the cooperation of stakeholders, NATS intends to drive operators towards better scheduling and schedule adherence (generally known as Arrive-on-Time) by By end 2015, NATS intends to receive and act upon A-CDM departure data from Heathrow and Gatwick. Between 2015 and 2020 the implementation of Runway Mangers (combined AMAN/DMAN) at Heathrow and Gatwick in conjunction with Time Based Spacing will enhance traffic synchronisation in the London TMA. 2 Where an aircraft transitions to an incorrect Flight Level (e.g. FL110 as opposed to FL100).

6 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Review and advise what work could potentially be shared about the projects NATS has made of the impact of TBS. Context Heathrow Airport currently operates to distance based separation (DBS) minima during the final approach phase of flight to 4nm from the runway threshold (4DME). Speed restrictions are applied on final approach meaning that during periods of medium and strong headwinds the ground speed of arrival aircraft slows and the time between successive arrivals increases. This can result in a significant drop in the landing rate during peak times. The knock-on effect is increased arrival holding, arrival flow regulation, and potentially significant schedule disruption. Time Based Separation (TBS) applies time-based wake turbulence radar separation rules on final approach, replacing the existing distance based rules used today. This will partly recover the reduction in achieved arrival capacity currently experienced in strong wind conditions on final approach. The amount of recovery is dependent on the proportion of wake turbulence separated pairs in the traffic, as well as other surveillance and runway operations separation and spacing constraints. TBS rules would be baselined to delivery in light headwinds, currently proposed to be around 5kt at 1,300ft (4DME). This means that in stronger headwinds the wake turbulence separation minimum would be reduced compared to current operations. In lighter headwinds, or tailwind conditions, the distance will be increased in comparison to today separation standards. Potential Benefits Benefit estimates are subject to revision (updates and downwards) as the concept evolves, and particularly as the safety case develops. TBS recovers lost movements during periods of stronger headwinds. This leads to lower delays and fewer cancellations particularly in strong headwind conditions. TBS also provides a more consistent time separation between arrivals leading to more consistent throughput and more predictable landing rate. Movement recovery Given the prevailing wind conditions at Heathrow, and the currently observed traffic mix, TBS recovers up to 5 movements per hour (number depends upon prevailing wind conditions and traffic mix in the hour). Benefits from TBS will be higher during periods with higher proportions of wake separated aircraft pairs on approach. If the future traffic mix evolves to increase the proportions of wake separated arrival pairs, the expected benefits would be greater (and vice versa). In periods of light winds and tailwind conditions, TBS adds additional distance to the separation minima in comparison to today s separation minima. This is a safety benefit that is expected to reduce the frequency of pilot reported wake turbulence encounters in these conditions. It also leads to a small reduction of the

7 potential landing rate in these, less frequent conditions. The potential landing rate is reduced to a level observed today in the baseline light wind conditions, which remains above the declared capacity. Predicted frequency of movement recovery at Heathrow 60% Relative Frequency 50% 40% 30% 20% 10% 0% Movements recovered per hour Movement recovery Low Medium High Av. Movement gain per operational hour Av. Movement gain per day TBS Recovered Annual Movements 527 2,006 2,373 Predicted delay reduction (majority holding delay): Delay Reductions Low Medium High Av. % Delay Reduction (as a % of current operational delays) 3% 18% 28% Av Holding Delay per Arrival (minutes) Arrivals per Day Av. Delay Reduction / Year (Minutes) 44, , ,760 Note the able above assumes that TBS would not be used of 0.5% of occasions due to preventative low visibility conditions. In some of the strongest wind conditions (>25kts at 4DME), the likelihood of recovering 3-5 movements per hour increases (but still depends upon traffic mix in the hour). In such conditions, the models predict TBS could provide around 50% reduction of the delays modelled under current operations.

8 Other Material Factors Regulatory approval from the CAA would be required before TBS could be used as it proposes a change to the current wake turbulence separation rules on final approach [1]. This will necessitate the completion of the data collected at Heathrow through LASER Interferometry Detection and Ranging (LiDAR) collection activity at Heathrow to support the associated safety methodology and analysis. References 1. Manual of Air Traffic Services, Part 1, Chapter 3 Section 9

9 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Advise how many times LVPs have are invoked at LHR and LGW in a typical year and what the triggers were. Context Low Visibility Procedures (LVPs) LVPs are designed to protect the runway from intrusion by vehicles or other aircraft when aircraft are departing or landing during periods of reduced visibility. CAT II/III ILS Procedures require that the Localiser Sensitive Area (LSA), and therefore the ILS Localiser Signal, is protected when aircraft are carrying out ILS approaches/landings and departing during periods of reduced visibility and/or low cloud cover. At both Heathrow and Gatwick airports, LVPs are triggered when Instrument Runway Visual Range (IRVR) is less than 600 metres or Cloud Ceiling is less than 200 feet [1]. Operational Impact Final Approach Spacing and Landing Rates At Heathrow during LVPs final approach spacing is usually 6nm with 10nm spacing behind an A380. This will result in a typical landing rate of 24 an hour. At Gatwick during LVPs final approach spacing is usually either 5nm or 8nm. This will result in a typical landing rate of between 10 and 15 inbounds an hour. Number of days when LVPs are in force NATS currently has basic data around LVPs. We don t have a record of whether LVPs have been triggered by IRVR (Visibility) or Cloud Ceiling. The data for Heathrow and Gatwick for the last three years is in the table below [2]. Heathrow Gatwick Year Hours in LVP Days in LVP Year Days in LVP : : : Average Average References 1. Heathrow and Gatwick, Manuals of Air Traffic Services Part Heathrow Airport Tower and Gatwick Airport Tower logs of recordable events.

10 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Consider the operational viability of Mixed Mode for capacity and resilience (particularly the switch on and off approach) as part of the review of the templates, including both the perspective of London Terminal Control and the Airport Tower operations Context Heathrow currently operates in segregated mode meaning one runway is used for landing aircraft and the other runway is used for departing aircraft. Mixed Mode would see both runways simultaneously used for landing and departing. The most efficient way of operating mixed mode at Heathrow is to allow fully independent departures and arrivals on each runway. This would allow the maximum benefit to be obtained, give the required resilience to the operation and give the best return on the investment made. ICAO Doc 9643 is the manual on Simultaneous operations on parallel or near-parallel Instrument Runways (SOIR). The distance between the Heathrow runways is c.1410m, to be fully compliant under current rules; 1525m is required. However between 1310 and 1525m independent operations are possible with current radar but a specific safety case is required to justify operations without radar upgrade. This is predicated on using an ILS, 1000ft separation until established on Final Approach, revised FIN/TWR communications and two Approach FIN controllers. As this is described in ICAO Doc 9643 it is possible the regulator would approve such operations at Heathrow provided that the conditions are complied with. Early engagement with SARG would be crucial and any deviation from ICAO Doc 9643 including procedures predicated on GNSS (RNP [AR]) which are not covered at present, may prove more difficult to gain approval on. Feasibility Mixed mode at Heathrow poses some significant operational challenges both at the Tower and in Terminal Control. To best understand these challenges, it is important to be clear about the proposed mode of operation. At the moment, the tabled proposal is for Compass departures and Terminal arrivals. This means that aircraft depart from the runway appropriate to the direction of the initial routing and arrive to the runway appropriate to their parking position. Compass departures carries with it issues of directional SID loadings. At the moment, Heathrow SIDs are predominantly loaded in South and Westbound directions which would mean a greater volume of traffic on the Southern runway. To achieve maximum capacity gains (+10-15% capacity) new SIDs are required. A second CPT SID, with a right turn after take-off, would be needed to balance the traffic. RNAV SIDs is also a prerequisite to reduce the turn angles required for 1 minute separations. In addition to this current SIDs are not deemed separated for the purposes of simultaneous departures from both runways. New SIDs and changes to current ones will of course require significant levels of public consultation. Previous Government consultation indicated that the public are very much opposed to Mixed-Mode as the Alternation pattern will be lost reducing respite from noise.

11 Operational Impact - Tower Perspective Compass departures will cause a significant increase in the GMC (Ground Movement Control) workload in getting departures to both runways at the same time and controllers will need an EFPS solution to designate the runway of departure. Terminal arrivals are less challenging for GMC as aircraft are delivered to the appropriate runway so ground conflictions are kept to a minimum. One of the main considerations when working through mixed mode is the application of runway usage. If the airport were to work mixed mode H24, this gives a very stable environment and the only consideration is to ensure that the gaps on final approach are best used to match the prevailing traffic. However, if mixed mode is to be used in a more tactical way (Switch On, Switch Off), work will be required; firstly, the actual methodology for switching from segregated to mixed mode, and vice versa, will have to be drawn up. Secondly, the technological solution to this is crucial: at the moment NATS have a standalone Arrival Manager (AMAN) and Heathrow Airport own the CDM platform, but Switch On, Switch Off mixed mode will demand that an integrated AMAN/Surface Manager (SMAN)/Departure Manager (DMAN) is available so that decisions taken are sent and the impact back engineered throughout the network. This integrated solution will also allow for a better tactical planning phase after the strategic phase detailed below. Strategic planning of a Switch On, Switch Off mixed mode will depend on the actual stipulations for switching modes of operation. If the plan were to run solely on times of day that are set and followed, this would give a more stable platform to follow but may not actually best serve the traffic requirement. For instance, if there is a schedule shift and this causes traffic demand to move outside of the times that are designated for mixed mode, there would be an anticipated significant increase in the delay generated. It would be far more beneficial for ATC to be able to utilise periods of mixed mode to best serve the prevailing traffic. The Heathrow Operational Efficiency Cell has the expertise and equipment to look at the schedule strategically and then, in conjunction with the key stakeholders, plan the operation at D-1. On the day of operation, the HOEC and VCR Sup, working closely with the TC Operations Supervisor, ensure that the flow rates and traffic arrive as predicted and fine tune the plan using the AMAN/SMAN/DMAN technological platform. This detailed knowledge of the schedule, followed by precision delivery on the day using an integrated technological solution is the only way in which a Switch On, Switch Off mixed mode operation could work without having significant GMC and delay impacts. Operational Impact - Airspace Perspective Currently we operate a Terminal Arrival operation between the hours of 0600 and 0700 when we use both runways for landing. In order to achieve this efficiently it requires high workload for supervisory staff and controllers. For Terminal Arrivals to work most efficiently inbound traffic is routed to the stack nearest the landing runway allocated. This can be done within TC airspace or can be done much further out by changing the aircrafts route. These stack swaps add complexity and can restrict outbound departure routes making them less efficient. By routing aircraft to a different stack you are potentially changing their route to a less optimum one which may not be their preference to fly. If aircraft do not route to the stack nearest to their landing runway they need be crossed over i.e. aircraft from the South stacks cross over aircraft landing on the South runway in order to land on the northern runway and vice versa. This is possible to do but adds complexity to the Heathrow approach operation and can make CDA s (Continuous Descent Approaches) more difficult to achieve. To manage mixed mode efficiently you would need a dedicated supervisor for Heathrow Approach. Currently one supervisor oversees the approach operation for five different airports. It is also highly likely that Heathrow Approach would be Split more often than today. Controllers Split sectors as they get busy and someone else takes some of their workload. This would require additional staff.

12 Mixed Mode would make Heathrow Approach more complex for the reasons mentioned. It is already a difficult place to train new air traffic controllers and mixed mode would inevitably make this job even harder than today. To fully exploit Mixed Mode, aspects of Queue Management would need to be accelerated in particular, scheduling and adherence to schedule and Runway/TMA Manager software. References 1. Heathrow Mixed Mode Concept of Operations. 2. ICAO Doc 9643.

13 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Look into whether further information can be provided about Point Merge and the likely timescales for implementation. Context Point Merge is an innovative method developed by the EUROCONTROL Experimental Centre (EEC) for merging arrival flows with existing technology including precision area navigation (P-RNAV). It is designed to enable extensive use of the flight management system and continuous descents, even under high traffic load. Point Merge has been studied and found feasible and beneficial in various generic environments in Approach (two, three or four entry points; one or two runways; and different TMA sizes) [1]. The concept is already used by the Irish Aviation Authority (IAA) to support air traffic operating within the Dublin TMA. Feasibility NATS is adopting Point Merge concepts as part of its on-going redesign of the London Terminal Manoeuvring Area (TMA) being undertaken by the London Airspace Management Programme (LAMP) investment, which has been established to provide a complete redesign of the London TMA to provide more efficient operations to all the airports in a manner that reflects progressive advances in aircraft capabilities (both avionics and performance) and addresses forecast future demand. Point Merge will be used in conjunction with (revised) Standard Terminal Arrival Routes to reduce the need for airborne holding in holding stacks. In effect, Point Merge sees the management of arrival streams on arcs from a common point (the merge point ) rather than utilising holding stacks, thereby providing environmental, safety and efficiency benefits. Such a concept fully accords with the CAA s Future Airspace Strategy (FAS) and the advanced concepts envisaged by SESAR for Terminal operations. Timescales LAMP is included as a key investment in NATS proposed capital investment plan in response to EC s Single European Sky second price control reference period 2 ( RP2 ) which is currently subject to customer consultation and subsequent CAA consideration. The current plan, which is subject to CAA approval of NATS RP2 Business Plan, envisages Point Merge concepts being deployed to support operations at Gatwick and London City Airports from 2015, and to Luton and Stansted Airports by winter Such concepts are however subject to public consultation as changes to the use or classification of airspace in the UK is managed in accordance with the CAA s Airspace Charter (CAP 724) and under the Airspace Change Process. References 1. Operational Service and Environment Definition (OSED) for Point Merge in Complex TMA, Edition , SESAR Project,, , NATS, Eurocontrol.

14 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Investigate and report upon Displaced Thresholds, identifying the extent to which NATS considers it feasible to displace thresholds at Heathrow Gatwick, Stansted and Manchester airports and any impact such displacements may have on operational service delivery. Context The threshold is that physical point on a runway where an aircraft aims to touch down. Operating a displaced threshold results in that point being further along the runway. Such a concept could apply to all aircraft (i.e. a permanent displacement) or to only some aircraft (i.e. a selective displacement with two thresholds), with each possibility leading to different types of benefits. Operating a displaced threshold would result in aircraft being higher above the ground at a specific distance from touchdown, with a resultant reduction in noise contours. The table below shows the difference in height (ft) for various distances from the threshold for various distances of displacement for a 3 degree glideslope. Distance to Touchdown (NM) Height (ft): no displacement Height (ft): 500m displacement Difference (ft) , ,592 1, ,184 3, ,777 4, ,369 6, Displacement: 500m Distance to Touchdown (NM) Height (ft): no displacement Height (ft): 750m displacement Difference (ft) , ,592 1, ,184 3, ,777 4, ,369 6, Displacement: 750m Distance to Touchdown (NM) Height (ft): no displacement Height (ft): 1,000m displacement Difference (ft) , ,592 1, ,184 3, ,777 4, ,369 6, Displacement: 1,000m Depending upon the distance between the thresholds on a runway operating a selective displaced threshold, further benefits may be enabled by a reduction in the distance between aircraft as wake vortex dissipates down to the ground. For example, increased runway occupancy may be achieved if separate displaced thresholds existed for aircraft with different wake vortex categories. Analysis [1] has shown that an aircraft which flies behind another one of any weight class can be sure to avoid wake vortex hazards when it flies at least 260ft higher than the preceding aircraft, which for a 3 degree glide slope, would require a distance of at least 1,500 meters between the two thresholds, which is a substantial proportion of runways operate din the UK. However, such a concept would not deliver lesser noise benefits that would otherwise result from all aircraft operating the displaced threshold.

15 Safety Issues A safety assessment would need to be undertaken to provide assurance that sufficient distance remained on a runway that used a displaced threshold to support all circumstances which may increase the amount on runway usually needed to achieve safe exit speed (such as landing heavy or a prevailing headwind component effecting ground speed on touchdown). All recent safety analysis of global accidents shows that the vast majority of aviation fatalities result from runway excursions and overruns. A very careful consideration would need to be given to reducing the amount of landing run available. Operational Impact A displaced threshold extends the touchdown point of an arrival flight to further down the runway compared to a non displaced threshold. The combination of time taken of the flight is flying over the runway before touch down and the additional time taken to decelerate on the runway results in an increase in runway occupancy time compared to a runway with a non displaced threshold. This, as well as other issues discussed below, will have an impact on overall runway capacity & utilisation. Heathrow The most significant issues presented by Displaced Thresholds at Heathrow is that all runway exits are designed to best suit traffic aiming to land at the current threshold. Operating a Displaced Threshold increases the likelihood of aircraft rolling past the commonly used runway exits, and in some cases this would significantly increase runway occupancy times as not only would aircraft have to roll to the next available exit, in many cases these next exits are not Rapid Exit points and therefore the harder turn (of the standard exit points) requires the aircraft to be even slower prior to vacating. This would have a significant impact at Heathrow where runway utilisation is currently so high. Such Displacements would also have an impact on any Mixed Mode operations at Heathrow, as has actually been observed in Kuala Lumpur. This is because the runway entry point (line up point) for departing traffic is typically located at the start of the physical runway to ensure maximum take off distance is available. A departing flight can commence line up after the arriving flight has passed the line up point. If the extended arrival runway occupancy time is greater than the time the departure takes to line up, then the departure has to wait an additional time before it can be cleared to depart. Furthermore, there is also an issue around landing clearances: in single runway operations the landing clearance had to be issued before the aircraft is over the concrete, rather than over the threshold meaning landing clearances have to be given earlier. Depending upon the distance of the Displaced Threshold down the runway, there may also be additional wake vortex issues. Gatwick Gatwick already operates mixed mode displaced threshold to both ends. The Arrival Runway Occupancy Time (arot) will always be greater than the Departure Line Up Time and its one of the reasons Gatwick operates such an efficient single runway operation. If the threshold was displaced further then the Rapid Exit Taxiway (RET) exit points would now be in the less than optimal position so the arot would likely increase to unacceptable levels. Given that Gatwick during periods Gatwick is operating at capacity, this would have an adverse impact on overall runway utilisation. Moreover, further displacement would increase the interaction of airflows between departing and arriving aircraft as the departure point and the touchdown zone would be closer together. A departing aircraft would still start its roll and take off from the current location (which itself depends on many factors, but can be considered to be a zone around the middle of the runway), whereas the arriving aircraft would land further down the runway (i.e. closer to the departure zone). Such a situation would result in the arriving aircraft travelling through airflows which are more displaced and turbulent than would be the case if it had landed earlier on the runway (i.e. further away from the stronger vortex created by the take off of the departing aircraft). Similarly, an arriving aircraft landing at the displaced

16 threshold will disturb air over a greater length of the runway, thereby exposing the departing aircraft a greater volume of vortex generated by the landing aircraft. Stansted Stansted already operates a displaced threshold (300m) on Runway 04 which was primarily put in for the Rapid Exist Taxiways (RETs) that already existed. Any further displacement would require additional RETs to maintain landing rates, otherwise a reduction in runway utilisation would occur. Manchester At Manchester the Rapid Exits and Normal Exists are designed around the existing threshold and normal deceleration. Even in today s operation (i.e. normal threshold), if an aircraft misses the last Rapid Exit Taxiway (RET), it taxis slowly down the runway taking the next exit, sometimes causing the following aircraft to abort its landing, circuit around airport and to be resequenced in the landing stream, increasing controller workload and reduced runway occupancy. A Displaced Threshold would make this more likely (unless additional RETs were built further down the runway), thereby increasing runway occupancy, potentially leading to a reduction in capacity. Technical Impact Such a concept would also require changes to the landing guidance system so that ILS glide slope is configured to support the displaced threshold. Selective thresholds would require separate ILS glide slope facilities so that aircraft are supported in their descent to the appropriate threshold. Furthermore, aircraft operating further down the runway as the result of a Displaced Threshold would result in a greater risk of aircraft entering the ILS Critical Area, thereby affecting the aircraft following them on approach, with a resultant impact on landing rates if such incursions of the ILS localiser & glideslope beams result in aborted landings. Summary The use or further use of Displaced Thresholds without a corresponding change to the location on the Rapid Exit Taxiway points would have an adverse impact runway utilisation and thus overall network capacity. Furthermore, a robust safety argument would need to be made to provide the type and level of assurance required to assert that such operations did not have an adverse impact on the safety of the operation: the vast majority of safety related incidents occur during the landing phase and any change that would increase the risk associated with that phase of flight would need to withstand extreme scrutiny. Moreover, the benefit a reduced noise footprint that would results from the use or further use of Displaced Thresholds would need to be validated to assess whether in made a material audible difference. References 1. Time Based Arrival Management for Dual Threshold Operation and Continous (sic) Descent Approaches, Eighth USA/Europe Air Traffic Management Research and Development Seminar (ATM2009).

17 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Investigate and report upon whether steeper approaches of 3.2 degrees could operate all day at Heathrow Airport without impacting runway throughput. Context The standard approach and landing process within the UK uses a 3 degree glideslope from when an aircraft establishes on the airfield s Instrument landing System (ILS) through to touchdown. Such an approach angle is recommended by ICAO [1] and nearly all UK airfields support such an operation, which state: Recommendation The ILS glide path angle should be 3 degree. ILS glide paths in excess of 3 degrees should not be used except where alternative means of satisfying obstruction clearance requirements are impractical. Any deviation would require the CAA to file a difference with ICAO and strong arguments would need to exist for them to be persuaded to do so. The only exception in the UK is London City Airport, where built up local topology leads to an approach of 5.5 degrees being used by suitably certified airframes and aircrew. Potential Benefits Operating a steeper approach of 3.2 degrees would result in aircraft being higher above the ground at a specific distance from touchdown, with a resultant reduction in noise contours. The table below shows the difference in height (ft) between a 3.0 degree approach and a 3.2 degree approach for various distances from the threshold. Distance to Threshold (NM) Height at 3.0 degree approach (ft) Height at 3.2 degree approach (ft) Difference (ft) , ,592 1, ,184 3, ,777 5, ,369 6, The different configuration of the thrust/airbrake/flap settings needed to achieve the required landing speed when flying a steeper approach, as well any difference to the time/distance to touchdown that the landing gear is deployed, will also have an impact on the ultimate noise contour.

18 Feasibility Purely from the perspective of providing Air Traffic Services at Heathrow airport, the use of a 3.2 degree glide slope is feasible but would require one-off changes to the ground-based airport navigation facilities (i.e. ILS glide slope transmitter the Precision Approach Path Indicator (PAPI) facility). If both 3.0 degree and a 3.2 degree glideslopes were supported, two sets of such facilities would be required. Operational Impact Provided that the aircraft landed at the same speed and at the existing threshold which exists for the current 3.0 degree approach, there would be no operational impact of adopting a 3.2 degree glide slope: runway occupancy would be the same. However, such an outcome should be considered in the context of the other issues set out in this briefing paper. Other Material Factors In addition to the ICAO Recommendation discussed above, NATS understands that not all aircraft are able to support an ILS auto-land at 3.2 degrees. The need to preserve that capability may require both a 3.0 degree and a 3.2 degree glide slope to be provided, with associated cost. Furthermore, if this measure is progressed on the basis that it will result in a lesser noise contour, then any impact of the increased or earlier deployment of the airbrake to achieve the required landing speed when flying a steeper approach angle would need to be included in that assessment. Moreover, there may be an impact on pilot workload to achieve the Stabilised Approach Criteria and this would need to be tested by airline operators. References 1. ICAO Standards & Recommended Practices, Annex 10, Volume 1

19 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Provide further information on the measure Creation of known surveillance environment including some case studies and information about the impacts of infringements, including reporting upon how many infringements on average occur in a year and their impact. Context UK airspace is constructed of defined volumes of controlled airspace and uncontrolled airspace, the latter being where aircraft are not constrained to operating to the rules associated with flight within controlled airspace. The busier airports are surrounded and protected by controlled airspace and it is generally established around the final approach tracks and the departure routes of the airport in question. This creates boundaries between controlled airspace and uncontrolled airspace which are defined by vertical and lateral dimensions. These boundaries are sometimes inadvertently crossed by aircraft operating outside controlled airspace and if they are not equipped with transponders to aid tracking of the flight and to help determine the height of the aircraft it makes it difficult to predict the risk posed to other aircraft under the control of Air Traffic Control (ATC). To ensure the safe operation at the airport, ATC either divert flights under their control away from the infringing aircraft or may even break off an approach to land or stop aircraft departing. At busier airports this can have a disrupting effect which impacts the efficiency of the operation, which can be significant at the very busy airports. Creating a known surveillance environment is achieved by establishing specified and defined volumes of airspace which requires all aircraft operating within them to operate a transponder to enable the aircraft to be visible to ATC. This would improve airspace safety and efficiency by increasing the number of aircraft who are known and visible to ATC and also detected by the anti collision safety systems of other aircraft. Currently Mode S transponders are only mandatory in class A C airspace and the establishment of Transponder Mandatory Zones (TMZs) is currently limited in UK airspace. UK airspace is classified from A to G. The London TMA is Class A, controlled airspace. To enter Class A airspace aircraft must have filed a flight plan and received an ATC clearance. They will be provided with an Air Traffic Control Service and must comply with ATC clearances and instructions. Aircraft must also maintain a listening watch on the appropriate radio frequencies. It is ATC s responsibility to separate all traffic in class A airspace from each other. Outside of controlled airspace, e.g. Class G airspace, pilots adopt a see and avoid principle, however, there is no requirement to carry any sort of transponder which aids the detection of aircraft. This mean they are invisible to Traffic Alert and Collision Avoidance Systems (TCAS) and other transponder alerting tools and although they can be seen as a primary radar return, ATC have no identity or height information resulting in reduced situational awareness. The boundaries of Controlled Airspace vary both laterally and vertically presenting a complex airspace environment, however modern GPS systems are able to display controlled airspace boundaries to assist pilots. When an aircraft infringes controlled airspace (enters without a clearance) the separation requirements that must be applied against that aircraft are 5 miles lateral or 5000 feet vertical separation and the blips must not merge. Normally within the majority of TC airspace the separation standard between aircraft is 3 miles or 1000 feet. The greater separation standards associated with infringing aircraft takes account of the fact that information on these flights may be very limited and their flight profiles can be unpredictable.

20 Avoiding action is taken against infringing aircraft on a regular basis. At Stansted for example the boundary of controlled airspace is very close to the airport, this means that as soon as someone infringes evasive action has to be taken. If an aircraft infringes controlled airspace close to an airport there is often no choice but to stop departures and break aircraft off the final approach. The CAA launched a public consultation in February 2008 proposing wider equipage of Mode S transponders in the UK. Some 1,900 responses were received, the vast majority coming from sporting and recreational pilots and associations, particularly the gliding sector. A number of concerns were raised, one being cost which has since reduced and it now only costs to equip an aircraft with a Mode S transponder. Despite improved ATC situational awareness, more efficient ATC alerting tools and TCAS the general aviation community stated there was no benefit to them. There was also a concern over perceived lack of suitable equipment for some types of aircraft such as gliders where powering a transponder can be an issue. As a result the CAA decided not to proceed with mandating Mode S transponder carriage. Controlled Airspace Infringement Data and Case Study Number of controlled airspace infringements recorded by NATS (Y.T.D.) In 2012 there was special temporary protected airspace around London leading up to and during the Olympic Games; this resulted in there being less infringements that year. It is estimated that 80% of infringements result in avoiding action being given or departures being stopped. Accompanying this report is a video file showing a typical controlled airspace infringement. FBZTL infringes the Stansted Control Zone which results in avoiding action being given to two commercial jets that are on Final Approach to Stansted. RYR3PU (Ryanair) and EZY79FC (Easy Jet) are both delayed through this action. In this example the infringer FBZTL is Mode S equipped which enables the controller concerned to ascertain the aircraft s call sign for follow up reporting and the controller has reliable height information from which an informed decision about what action to take can be made.

21 Feasibility Mandate Mode S Carriage The ideal solution would be for all aircraft to be mandated to be Mode S equipped in all airspace classifications from Class A to Class G (uncontrolled airspace). This solution would give ATC much better situational awareness of aircraft tracks and enable more informed decisions to be made around whether an aircraft has or hasn t infringed controlled airspace. It would increase the effectiveness of various ATC alerting tools and TCAS. Mode S would give ATC a clear indication of the height an aircraft is at and as a consequence ATC would be better able to judge whether that aircraft had in fact infringed controlled airspace. With this knowledge the separation rules which must be applied against aircraft that have infringed controlled airspace could potentially be relaxed meaning evasive action taken with commercial air traffic would cause less delay than today. In order to mandate the carriage of Mode S and realise the clear safety benefits the CAA would need to adopt a different stance in relation to the views and concerns of private pilots which it has historically been sympathetic to. Expand use of TMZs A TMZ is defined as a volume of airspace where aircraft wishing to enter or fly within the defined volume will be required to operate as a minimum with Mode S Elementary SSR equipment which includes a pressure altitude reporting transponder. Aircraft so equipped may access the TMZ without ATC approval. In the London TMA there is currently one TMZ in the vicinity of Stansted. More TMZs could be established around other airports and areas of intense air traffic. TMZs in their current form do however impact on ATC workload, creating more of them in their current form is likely to increase workload which could be detrimental to capacity. The CAA is empowered to introduce additional mandatory transponder carriage requirements without formal public consultation. However they have decided they would use the Airspace Change Process (ACP) to process requests for the establishment of TMZs. Review Current Separation Standards The separation requirements that must be applied against that aircraft are 5 miles or 5000 feet and the blips must not merge. These have been in place for some time and could be reviewed by SARG with a view to reduce the requirements. Other Ideas NATS are assessing the viability of developing a UK standard for a portable, low cost, Low Power ADS B transceiver (LPAT) for use on GA aircraft outside controlled airspace. This has been validated through the development of a prototype and the CAA has been supportive of this initiative. The aim of this device is to enhance the pilot s awareness of nearby traffic by promoting the see and avoid principle to reduce the likelihood of mid air collisions involving GA and to reduce the number of Controlled Airspace Infringements. The project aims to develop a standard for an electronic conspicuity device which is more affordable than Mode S. It will also investigate how ADS B could be enabled on existing capable Mode S transponders so that users can also benefit from ADS B to gain similar functionality to the LPAT but without the requirement to buy a new device. This would significantly enhance the successful adoption of this concept and would provide a major advancement in general aviation safety.

22 References 1. NATS LPAT Overview Issue MATS Part 1 3. MATS Part 2 (LTC) 4. CAA Mode S Fact Sheet 5. CAA Mode S Phase II Consultation

23 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Provide further information on the measure Civil-military airspace optimisation, including the problem this measure is trying to address and the impact of adopting these measures. Context Airspace within the UK is categorised into seven various types (A to G), each with a different set of criteria and operating rules (i.e. Instrument Flight Rules or Visual Flight Rules). Classes A, B, C, D and E cover Controlled Airspace, where, inter alia, traffic must be in receipt on an ATC clearance from an approved provider of Air Navigation Services. Civil air traffic operations predominantly 1 operate within Controlled Airspace within a structure of defined volumes of airspace (called airways ) established to provide safe and expeditious service delivery. Outside Controlled Airspace supports a more relaxed set of rules and a clearance from ATC is not required. Most of General Aviation operate outside controlled airspace. Military operations predominantly occur in Outside Controlled Airspace, with any need to enter Controlled Airspace being coordinated between civil & military controllers. Airspace assigned for a specific military function and where a large degree of operating autonomy is required (such as to support fast jet training or air-to-air refuelling) is termed a Danger Area. These are specifically defined by lateral and vertical boundaries and their existence and location promulgated to all potential airspace users to ensure no unauthorised access (irrespective of whether an aircraft is in receipt of any form of ATC service or not). Implications In many cases, the Danger Areas are located at high level and over water (e.g. the North Sea, the Irish Sea and the Celtic Sea) where the large lateral and vertical confines allows unrestricted operations. Such large swathes of airspace do however have an impact on civil air traffic operations, becoming manifest through additional controller workload and sub-optimal routings with traffic needing to be routed around an active Danger Area. Historically, such areas would be restricted solely for military use, irrespective of whether they were actually being used (i.e. active ). More recently (i.e. from c.2005 onwards), with the drive to provide more efficient services to civil operators and the reduction in their usage by the military, the concept of the Flexible Use of Airspace has enabled such airspace to be shared for civil & military purposes, with effective arrangements established with the MoD for NATS to use airspace ordinarily allocated to the MoD when not required, arrangements that are supported by robust and effective safeguards to ensure that the safety of operations in not compromised. The Joint Airspace Management Cell located at Swanwick is tasked with providing that service. Most of the military s need for airspace comprises military aircraft, although some testing of live ordnance requires use of airspace. 1 Some civil air traffic operates outside controlled airspace whilst in receipt of an Air Traffic Services Outside Controlled Airspace (ATSOCA) service.

24 One particular location is MoD Shoeburyness on the south-east Essex coast. Due to the hazardous nature of work carried out at MOD Shoeburyness (i.e. live ordnance testing), an Air Danger Area has been established by the Civil Aviation Authority (CAA) around Shoeburyness and Foulness, and is activated when any of the Ranges D136, D138, D138A or D138B are being used. Danger Area D136 and D138 extend from surface up to 13,000ft, with D138 and D138A occasionally extending to 60,000ft subject to prior notification. The location of these particular Danger Areas, i.e. in the eastern part of the London TMA, presents a significant impact on traffic operating into Heathrow and London City Airports, especially when they are operating to the upper level of 60,000ft. Procedures exist at London Area Control and London Terminal Control to ensure that under such circumstances civil air traffic is routed around these areas to maintain safe operations. Such routings do however result in sub-optimal trajectories as they incur additional track-miles, with consequential fuel costs and environment dis-benefits. Furthermore, en-route and terminal capacity is reduced when these Danger Areas are operating at the 60,000ft ceiling (and to a lesser extent at the usual 13,000ft ceiling). Other examples that have a significant adverse operational impact on efficient civil air traffic operations include: the Danger Area supporting RAF Weston-on-the-Green (Oxfordshire) which is used for basic military parachute jumping (extending up to 12,000ft); The Danger Areas used by the Royal Navy in and around the Portsmouth area, used for a variety of naval activities (including live firing and Unmanned Aerial Vehicle operations on and around the Solent), and which extends from surface up to 55,000ft in several locations; and, The group of Danger Areas collectively known as Salisbury Plain, where live firing, bombing, parachute dropping and unmanned aircraft operations, which requires airspace from surface to up to 50,000ft. The Aeronautical Information Publication [1] sets out the confines of such Restricted/Danger Areas. The impact on civil operation of these is summarised in Annex A. NATS works closely with the MoD to both maximise the use of airspace Outside Controlled Airspace to the MoD and minimise the impact on NATS operations and its customers. The on-going review by the Airports Commission into possible measures that may increase both capacity and resilience in the south-east of England presents an opportunity to review whether, in the light of recent and on-going defence reviews and the impacts that the use of Danger Areas have on civil operations, the right balance still exists between all stakeholders in respect of efficient access to and use of such a scare resource. References 1. UK Aeronautical Information Publication, ENR

25 Annex A: Impact of Key Danger Areas in S/E England on Civil ATS Operations Shoeburyness Stansted departures have to route around Shoeburyness to exit the London FIR via Dover (DVR), preventing direct routing that would otherwise reduce controller workload and provide more fuel efficient flight profiles. In LAMP, Southend arrivals from the South have to route around Shoeburyness, preventing direct routings with consequential impact on controller workload and preventing fuel efficient flight profiles.

26 A holding stack for London City and Biggin Hill would be ideally located over Shoeburyness. LAMP has to position this to the East of the Danger Area which adds track miles (with assocaited fuel costs and environmental disbenefits). Approximately two days a year, Shoeburyness activates up to 60,000ft. This requires flow restrictions on UK arrivals from the East to make sure the controllers can stream the arrivals to the North of Shoeburyness.

27 Portsmouth Approximately two days a year, Portsmouth activates up to 55,000ft. This requires flow restrictions on all UK arrivals via BREST arrivals to make sure the controllers can stream the arrivals to the West of the Danger Areas. Salisbury Plain Causes limited disruption to traffic, but when operational prevents aircraft receiving more direct routings, which would reducing complexity and provide more fuel efficient flight profiles.

28 Weston-on-the-Green When active requires civil ATS operations us to remain at least 5nm+ away. Located in the middle of 2 TMA sectors which adds considerably to complexity and controller workload.

29 NATS Support to the Airports Commission Task 2.2b Package Potential Measures Tasking This briefing note responds to the action placed on NATS to: Advise whether NATS would be content to share (with the Airports Commission) the work NATS has undertaken with Heathrow Airport on the Compton SID and the projected benefits of the upcoming trial; and Investigate and report upon potential reductions in separations between SIDs, providing beneficial evidence and how this could be implemented at Heathrow. Context The Departure Enhancement Project (DEP) has been created as the first step towards the systemisation of Terminal airspace and the efficient use of Performance Based Navigation (PBN) operations. It intends to inform new national standards regarding reduced angles of divergence for 1 minute departure intervals from a single runway and the placement of PBN routes against established holds. To help achieve these aims, DEP has been set up a Maturity of Cross Organisational Relationships (MACOR) project in partnership with the CAA. Status DEP is primarily a research project which is designed to inform large scale airspace projects including London Airspace Management Project (LAMP) and Northern Terminal Control Area (NTCA) with regards to airspace procedures and safety assurance. DEP will support LAMP and NTCA in their fundamental review and redesign of the current airspace infrastructure in Terminal Airspace. Through the introduction of systemisation, DEP also supports the SESAR Target ATM Concept and FAS Deployment Plan (the UK's approach to the advanced operational concepts being validated by SESAR). The project contains a programme of research, simulations and operational trials which will take place over the next 2 years. It is currently in the early stages of its Feasibility and Options phase, and as such has so far conducted a number of real time simulations and a series of analysis to develop the operational concepts and shape the planned trials by supporting the design process and safety assurance. As DEP is yet to introduce its first trial, which would provide the first evidence for our investigation, we are unable to report on the potential reduction in separations between SIDs or provide any evidence. However, the concepts being explored in DEP could lead to the following, provided they are proved acceptably safe and are able to be successfully integrated into the network: Reduced angles of divergence of departure, which if proved acceptably safe would enable better positioning of departure routes and an increased number of them; Off Load SIDs in conjunction with the above, providing more departure capacity in a single direction with the aim of reducing ground delay; Redesigned SID routes, more reflective of where ATC tactically vector aircraft against ATC obstacles (holds and inbound routes), with the intention of reducing ATC workload and potentially providing a capacity improvement; and, Redefinition of the Heathrow Terminal holds to RNAV1 standard with the aim of providing a smaller containment area enabling better route spacing against them, which may lead to a capacity benefit.

30 The planned trials are focussed on Heathrow and Gatwick Airports. However once the concepts are proven they should be applicable to other airports and would be implemented following local safety assurance. The DEP key trial threads are: Heathrow Midhurst SID Trial: In service of establishing the safe separation distance between the RNAV SID and a conventional hold, and gathering additional RNAV 1 track keeping data; Gatwick BOGNA SID Trial: In service of separation against conventional hold and operational trial of route placement in service of reduced departure separation; A trial of a redesigned Heathrow Compton SID pair: In service of proving reduced departure splits, parallel offload departure routes and resolving Compton hotspot; and, An RNAV Holding trial including RNAV STARS replication - in service of improved containment and MET resilience of holding aircraft The DEP trials are intended to be iterative, so that the trials build on evidence gathered from previous threads.

31 NATS Support to Airports Commission: Clarification of Matters Raised on NATS Submission of Task Form 2.2b Package Potential Measures NATS is pleased to provide the following clarification to some of the issues raised during review of the material developed under Task Form 2.2b Package Potential Measures. These take the form the matter on which clarification is sought being identified in speech marks and the corresponding the answer/ explanation set out in red text below. Request Consider and advise what can be shared in respect of NATS work on Arrival Queue Management particularly about the projected impacts. By 2020, with better scheduling available within the industry, accurate data and integrated runway management tools This is referring to the integrated use and interchange of arrival and departure information between Arrival Manager (AMAN), Departure Manager (DMAN) and, ultimately, a Runway Manager (RMAN) systems at airports to provide more efficient operation and the tools discussed further in the briefing note. Time Based Separation (TBS) to support Heathrow and Gatwick arrivals, Departure Management (DMAN), Arrival Management (AMAN) and Time Based Flow Management (which uses extended AMAN techniques) Time Based Separation will sustain landing rates with a headwind component of greater than 5 knots. Departure Manager (DMAN) is a planning system to improve departure flows at airports by calculating the target Take Off Time (TTOT) and Target Start up Approval Time (TSAT) for each flight, taking multiple constraints and preferences in to account. NATS is developing DMAN systems. Arrival Manager (AMAN) is a planning system to improve arrival flows at airports by determining the optimal landing sequences taking multiple constraints and preferences into account. This system was seen at the TC during the visit to Swanwick. Time Based Flow Management is a concept that will extend to working horizon for AMAN to up to 500 nautical miles to maximise the opportunity for linear holding (i.e. speed control in the en route phase of flight to arrive at Top of Descent at a time where no or significantly reduced airborne holding (stacking) is required before the aircraft starts its approach phase). New procedures whereby controllers reduce aircraft speed in the descent in order to reduce average stack holding by an anticipated 2 minutes at Heathrow This is the concept of linear holding speed control is applied to arrive at a downstream point later to avoid having to queue/hold for that period (more fuel efficient). QM concepts and techniques The term was used in a generic sense to cover the maters mentioned earlier in the briefing note e.g. improvements to AMAN; Time Based Separation; and linear holding. drive operators towards better scheduling NATS and airline operators attend various service delivery forums to examine, inter alia, how operations will be improved by new ATM systems, concepts and operations. The deployment of the tools and

32 concepts that will be delivered by the QM programme will enable NATS to advise customers of the additional capabilities that will be delivered and the opportunities that more efficient airline arrival & departure scheduling will deliver. Currently, some operators regularly arrive at the holding point ahead of schedule to ensure that they touchdown on time. With the greater planning and predictability that QM will deliver, NATS will be able to set out the benefits to operators of adherence to the agreed arrival schedule. Between 2015 and 2020 the implementation of Runway Mangers (combined AMAN/DMAN) at Heathrow and Gatwick in conjunction with Time Based Spacing will enhance traffic synchronisation in the London TMA This points to the mutual use and interchange of arrival & departure information by the AMAN (supplemented by TBA information) and DMAN systems to increase the arrival, turnaround & departure flows. Request Advise how many times LVPs have are invoked at LHR and LGW in a typical year and what the triggers were. Final Approach Spacing and Landing Rates This depends upon satisfying wake vortex criteria. The table below sets out the current distance based separation criteria that are required to be achieved at 4 Nautical Miles (NM) from the airfield DME. Follower J H UM LM S L Leader J H UM * * LM * * * * 3 5 S * * * * 3 4 L * * * * * * * = no wake vertex constraint but the minimum radar separation applies J H UM LM S L Super Heavy Heavy Upper Medium Lower Medium Small Light

33 The majority of traffic is between 3NM and 5NM as determined by the vortex mix of the traffic presenting. This results in a typical landing rate at LHR of 42 per hour, with a light headwind of 5 knots. 78:41 This means 78 hours 41 minutes. Request Look into whether further information can be provided about Point Merge and the likely timescales for implementation. The current plan, which is subject to CAA approval of NATS RP2 Business Plan, envisages Point Merge concepts being deployed to support operations at Gatwick and London City Airports from 2015, and to Luton and Stansted Airports by winter 2019 Heathrow will be supported by the concept of Tromboning, also known as non point merge, where arrivals are sequenced in a route structure, with typical vectoring patterns as used by controllers today. The complexity of the airspace around Heathrow lends itself to the concept of Tromboning rather than Point Merge. Request Consider the operational viability of Mixed Mode for capacity and resilience (particularly the switch on and off approach) as part of the review of the templates, including both the perspective of London Terminal Control and the Airport Tower operations RNAV SIDs is also a prerequisite to reduce the turn angles required for 1 minute separations. In addition to this current SIDs are not deemed separated for the purposes of simultaneous departures from both runways Currently we use conventional SIDs at Heathrow. If SIDs diverge by 45 degrees we can apply a 1 minute split between them i.e. one turns left the next turns right. If two consecutive departures go on the same SID or two SIDs that do not diverge by 45 degrees, then a two minute separation must be applied. It is envisaged that by using RNAV SIDs the 45 degree requirement could be reduced to degrees (which is what is used in the USA) which potentially means more one minute splits between departures could you used. This gives the airport Tower controllers greater flexibility. It is worth adding to this that we currently cannot depart from both runways simultaneously, to facilitate mixed mode this would need to addressed. To fully exploit Mixed Mode, aspects of Queue Management would need to be accelerated in particular, scheduling and adherence to schedule and Runway/TMA Manager software The purpose of Mixed Mode operations at Heathrow, as opposed to Segregated Mode, is to raise runway throughput to approximately 50 movements per hour per runway. Total 100 movements per hour (sustainable) up from 84 (+15%). To achieve this, a sophisticated schedule is required to maintain a balance of arrivals and departures across the day which evenly loads both runways and avoids periods of insufficient traffic or too much traffic. Better use of the airport will be achieved by close adherence to the planned schedule. This is true today but is more important in Mixed Mode.

34 This still leaves a requirement to manage traffic across both runways in a dynamic sense. Referring to the Concept of Operations, in simple terms departing traffic must use the runway commensurate with the direction of turn after take off (Northbound to North runway, Southbound to south runway). This is known as Compass Departures. Conversely, arriving traffic would normally approach the runway nearest to the destination terminal. This is known as Terminal Arrivals. Furthermore, departing traffic does not always exhibit a perfect North/South split. To combat this, some SID tracks are duplicated on the North and South runways although they retain separate tracks initially. In order to ensure a good balance of traffic (optimise runway usage), planning decisions need to be made up to 40 minutes ahead such that arriving and departing traffic is correctly allocated to each runway and arrival spacing regimes are suitable. This planning requires good co ordination between Tower and TC Heathrow and is best achieved with Runway Manager Software; or what is currently known as combined AMAN/DMAN + Airport CDM. Heathrow Mixed Mode Concept of Operations. This is attached to this clarification material. Request Investigate and report upon whether steeper approaches of 3.2 degrees could operate all day at Heathrow Airport without impacting runway throughput. Provided that the aircraft landed at the same speed and at the existing threshold which exists for the current 3.0 degree approach, there would be no operational impact of adopting a 3.2 degree glide slope: runway occupancy would be the same No. An increased angle of 3.2 degrees would not impact on the hourly throughput of the runway provided that the current speed control on arrival is not compromised. pilot workload NATS has received feedback from BA that it would need to establish the best low power / low drag approach which meeting the Stabilised Approach Criteria at 1,000ft (in final landing configuration) see below which does not result in unacceptable pilot workload to achieve and sustain this. Stabilised Approach Criteria At 1000 Radio Altitude aircraft must be: In planned landing configuration (gear down, land flap). Stabilised on correct vertical profile Stabilised at target approach speed Should these criteria not be met at 1000R, a mandatory Go Around must be flown. This policy is a cornerstone of safely minimising runway excursion risk.

35 Request Advise whether NATS would be content to share (with the Airports Commission) the work NATS has undertaken with Heathrow Airport on the Compton SID and the projected benefits of the upcoming trial; and, Investigate and report upon potential reductions in separations between SIDs, providing beneficial evidence and how this could be implemented at Heathrow. reduced angles of divergence Various options are currently being simulated. A reduction from the 45 degree divergence currently operated would need to be supported by a safety case. A trial of a redesigned Heathrow Compton SID pair A simulation of a revised SID pair is currently underway. The purpose is to reduce the departure angles that accompany 1 minute departures. Post trial it is hoped that enough credible data will have been gathered to provide the necessary safety assurance to move towards implementation based on 1 minute, or equivalent, departure separation.

36 NATS Support to Airports Commission: Clarification of Matters Raised on NATS Submission of Task Form 2.2b Package Potential Measures NATS is pleased to provide the following clarification to some of the issues raised during review of the material developed under Task Form 2.2b Package Potential Measures. The clarification takes the form of the matter highlighted and corresponding query being set out, followed by the answer/ explanation in red text below. 1) Request In response to a question I had on point merge and Heathrow, tromboning was mentioned as the way arrivals will be managed into Heathrow. Are you able to provide me with more information as to what this is and also what the likely timescales are for implementation? Tromboming is a concept whereby aircraft equipped with PRNAV capability can route to a specific point on the arrivals path from (point A). It is termed tromboning as the converging arcs look like a tombone. Heathrow tromboning is not likely to be implemented before 2018 as it is dependent on the TA change. The current Transition Altitude (TA) needs to be raised before this can be implemented. The plan is to move the current stacks further out and then the trombone route from the stack to base leg will enable continuous climb departures. Tromboning is an enabler for continuous climb departures. Direction of travel to touchdown A 2) Request Steeper approaches I m not sure whether I was clear on my question. I understand that provided that the aircraft landed at the same speed and at the existing threshold, there would be no operational impact of adopting a 3.2 degree glide slope: runway occupancy would be the same. My question relates to whether it is possible to maintain existing runway throughput even if aircraft land with a steeper glide slope, given the speeds that aircraft need to adopt to land safely at Heathrow. It is possible to maintain existing runway throughput at Heathrow with aircraft approaching on a steeper glideslope of 3.2 degrees.

37 3) Request A trial of a redesigned Heathrow Compton SID pair What are the timeframes attached to the work underway to simulate the revised SID pair and what is the timeframe for implementation. Real Time Simulations are planned for later this year. Subject to operationally feasible and beneficial outcomes, the revised airspace structure in spring 2018 (timescales as identified in the LAMP summary business case submitted in August). 4) Request Creation of a known surveillance environment I have some comments/questions on the briefing note which is attached. I do have a fundamental question with this measure and also the next one in the list which is, do these measures actually require Commission support or are they options that are already actively being taken forward with NATS and CAA? It is worth emphasising that the best solution for creating a known surveillance environment would be mandating Mode S SSR carriage in all airspace categories A G. In this environment there is the potential to reduce the separation standards that must be applied against aircraft who have infringed controlled airspace. Mandate Mode S Why would this option be any different this time round? Presumably the same issues that arose out of the last CAA consultation would arise? The cost of retrofitting Mode S to non equipped aircraft is now significantly cheaper, approx. 1,500 1,800. The problem of infringing aircraft tends not to be caused by gliders so perhaps the CAA could look at mandating Mode S on all powered aircraft, this would overcome the concerns raised around not being able to sufficiently power the device. The CAA were quite sympathetic to General Aviation users, you will see from the infringement data this problem is not improving so it needs to be re addressed. Perhaps the Commission could influence the CAA to look at this again as their previous steps have not had a big enough impact. Why haven t more TMZs been introduced? Also the last line mentions that the CAA wish to use the ACP to process requests for the establishment of TMZs. Are you expecting to seek more TMZs as part of the LAMP project and the various ACPs that will be needed to support that? How would this be detrimental to capacity? And does this outweigh the positives of this proposal? Currently TMZ s are beneath controlled airspace. Anyone can fly through them providing they are Mode A and C or Mode S equipped and there is no requirement to talk to ATC. Frequently aircraft who are not suitably equipped want to fly through them. In order to do so they will contact Farnborough LARS (who provide a radar service outside of controlled airspace) who will identify the aircraft and then contact ESSEX radar to arrange transit. This coordination process adds to ATC workload.

38 If ATC observe a primary radar return inside the TMZ they must treat it as if it was an infringing aircraft and take evasive action etc. even though the TMZ is not controlled airspace. This adds to ATC workload and delays commercial air traffic. LAMP is not proposing any additional TMZ s. The current rules around TMZ s mean in their current form the creation of more could be detrimental to capacity. LPAT Is this by providing situational information about other aircraft in the vicinity? Yes. LPAT is an acronym of Low Power ADS B Transceiver, equipment that broadcasts its location and is detected by other LPAT equipment to enable pilots to be aware of the location of such aircraft. What are the timeframes for this? NATS are planning that by the next flying season in 2014 to have sufficiently developed a product for a supplier to manufacture and sell. After that it will be up to the market to consider whether this product provides sufficient benefit to warrant its take up.

39 5) Request Civil/Military airspace optimisation there is some detail in the note about the danger areas. What I am not so clear about is what the actual impact is on ATC aside from the high level narrative about less than optimum routes. Are there any specific examples of routes that are currently sub optimal and what is the impact of this on them? There are many examples of routes that are not as optimal as they could be due to the presence of active danger areas such as L610 and L172 (which transit the Shoeburyness area) and L950 and 859 (which are adjacent to the Portsmouth danger area). These results in additional track miles flow, thereby using more fuel that would otherwise be necessary. ATC workload increases and capacity is reduced whilst such areas are active and cannot be used for civil ATC purposes. The graphic overleaf shows the location of the main Danger Areas and how these are dovetailed by Controlled Airspace. The Danger Areas are shown in red; Controlled Airspace is depicted as the dark areas and which have varying base and ceiling levels. As the diagram shows the current airway structure into the London TMA is very much designed around the danger areas. In particular the Boscombe Down, Portsmouth and Shoeburyness danger areas. Instead of aircraft flying direct to their respective airport the airspace structure dictates that they route around danger areas. This creates a less optimal route which uses more track miles and consequently more fuel and the associated cost. If the danger areas were not there it would enable more direct routings and wider airways which could lead to an increase in en route capacity.

40

41 6) Request Displaced thresholds Heathrow mentioned that there could be conflicts between ILS and ground vehicles and aircraft taxing to the runway if they were over a certain height were the runway s thresholds to be displaced. I think you allude to this in your briefing note but could you be a bit more explicit of what these ground movement restrictions/conflicts are? Through displacement of the threshold it would be necessary, in order to retain ILS (& MLS) operations, to move the ILS Glide path equipment (and MLS Elevation and associated touchdown associated systems). In doing this the equipment would move inwards toward the centre of the runway (assuming existing length of runway remains as existing). This move would then bring, previously unsafeguarded areas into the ILS illuminated zone from which there is the potential that the ILS (and MLS) beam could be subject to increased levels of interference. This can be caused by both static and moving objects in and around the airfield. An example to illustrate the potential complication of taxiing aircraft is that when landing on Runway 27L, if the ILS beam was positioned further down the runway then the eastern end of the Sierra taxiway, possibly crossing SB3 and access / egress from the Victor stands would be affected and would require more intensive ATC control in order that they do not interfere with the ILS (& MLS) when 27L is the landing runway, and therefore appropriate action will need to be taken; this could require modified taxiing, runway crossing routes and hold points to be used for Terminal 4 departures taxiing to Runway 27R or the maintenance area. In turn these additional manoeuvring restrictions would likely restrict ground capacity and increase ground movement workload. A detailed assessment would be required to identify specific issues relating to a change in ILS equipment position. Any move of the ILS glide path (& MLS) would require new and larger safeguarded areas to be imposed thus increasing the level of restricted movement around the runway / taxiway areas. Currently the safeguarded zones, Critical and Sensitive areas [CSA] are from the antenna to threshold (critical) and into the undershoot area (sensitive) by moving the ILS Glide path (& MLS Elevation) antennas, the CSA are brought onto and encompassing more of the manoeuvring area.

42 NATS Support to the Airports Commission Task 2.2c Developing Forward Strategy Tasking This briefing note responds to the action placed on NATS to: Northolt. What conflicts exist between the arrival and departure routes into and out of Northolt and Heathrow? How would an increase in civil movements at Northolt (within the CAA restrictions on runway usage) impact on these conflicts? Currently the Standard Instrument Departures (SIDs) from Northolt are in direct confliction with SID s from Luton airport. This means that only one aircraft can be released form either airport at a time. Luton has free flow on some of their routes which is suspended every time a conflicting Northolt wishes to depart. A backlog of aircraft waiting to depart in turn can frequently exist. Inbound aircraft to Northolt are worked as if they were an inbound to Heathrow. If there are delays into Heathrow efforts will usually be made to force the Northolt inbound down early so that it can under fly the Heathrow stacks and not be delayed, this increases workload for both the TMA controller and Heathrow approach. Any action that takes an aircraft off its flight planned route increases workload. Whilst we have relatively low numbers of Northolt inbounds we can force them down under the stack but this is not always possible and if there were greater numbers the opportunities for doing this reduce. In this instance, a Northolt inbound could get in the way of a Heathrow inbound. We can currently cope with limited numbers of Northolt arrivals with minimal impact on Heathrow but if they were in greater numbers there could be a big impact on the Heathrow operation. The runway at Northolt would ideally need to be re oriented East/West to be parallel with the existing runways at Heathrow. In its current runway configuration and due to the proximity to Heathrow, traffic has to be integrated with that of Heathrow. Any significant increased use in future would require a review of the airspace and the way in which Northolt traffic is integrated with other airport traffic, particularly that of Heathrow and Luton. If Northolt was to expand it may not be possible to remove the Northolt inbounds from the Heathrow inbound numbers in this way, resulting in an impact on both Northolt and Heathrow operations. A Northolt inbound follows the same arrival as a Heathrow inbound so when they are left on their original flight planned route they are worked as if they were a Heathrow inbound. In this instance, one Northolt inbound is equivalent to one Heathrow inbound. The SIDs that support Luton are set out in the UK Aeronautical Information Publication. As can be seen, they set out a complex set of flight paths, necessitated by existing departure & arrival routes from other London airports. If operations did increase, then as well as the impact on Heathrow and Luton operations, the length of the runway (1,687m) would impact the type of aircraft that could operate from the airport and thus the location of the destinations served. In comparison, Luton is 2,160m and London City 1,508m. A runway of this length would not be able to support heavy wide bodied aircraft flying long haul, and, subject to further investigation, would be limited to aircraft of Upper Medium wake vortex category and below (with representative aircraft set out below).

43 Note: the Airbus A380 is categorised as SUPER HEAVY

44 NATS Support to the Airports Commission Task 2.2c Developing Forward Strategy Tasking This briefing note responds to the action placed on NATS to: Westerly Preference. To provide a briefing note of the work that has been undertaken in the past on this matter following engagement by HAL on this matter. Additionally, to advise what if any airspace changes would be required to support a move away from a westerly preference. METAR weather data were as analysed in order to gain an understanding of surface wind conditions at Heathrow Airport, and the potential impact wind can have on the operation. An example of a METAR report is presented at Annex A. During the sample period ( ), 51% of the recordings had a headwind of less than 5 knots. The remaining data showed a head wind of 5 knots or greater (see Annex B for an example showing the resolution of wind speed and direction into perpendicular components). However, this does not necessarily mean that the operation would be westerly s during this time: if the forecast for the day was easterly then the operation would have started in that made and would have remained in that mode during the day unless the wind changed to at least 5 knots westerly. Using the current accepted tailwind limit of 5 knots, ground wind conditions would permit runway operations in either direction during these periods. As a result 87% of the METAR recordings would permit westerly operations, 63% of recordings would permit easterly operations. These values are increased to 91% and 72% respectively during the night time period as wind conditions are generally calmer at night. Thus 87% of the time the METAR wind recordings were such that either there was a westerly wind or there was an easterly wind less than 5 knots. As a theoretical exercise, airborne wind data (sample from ) for aircraft on approach to Heathrow at 3000ft was also assessed, concluding that wind speeds at 3000ft were generally 5-15 knots stronger than those on the ground. As a result, there are fewer periods where 3000ft wind conditions would permit runway operations in either direction. 3000ft wind speed & direction is one of the contributory factors for runway direction choice. If the runway direction was based solely on 3000ft wind observations, then there would be fewer opportunities to utilise a preference, east or west. Analysis of runway end changes during 2012 revealed that changes during the operational day are infrequent. Choice of runway direction is affected by many different factors, but analysis of triggers for runway end changes revealed that wind conditions are prominent amongst them. Changing from westerly to easterly operations increases the average distance flown by aircraft after leaving the holding stacks by an average of 12NM. This is as a result of the location of the stacks - two central to the airport and two to the east of the airport. In an easterly preference scenario there would be a higher likelihood of requiring end changes (because the prevailing wind is naturally westerly) during the operational day compared to a

45 westerly preference scenario. Operating an easterly preference would therefore lead to potential increases of inefficiency due to runway end changes and hence increased levels of delay and fuel burn etc compared to a westerly preference scenario. A runway end change would require a move from westerly s to easterly s or vice versa. However, no airspace changes would be required to move away from the westerly preference: such operations (i.e. easterly) are regularly provided and supported by the existing operation.

46 Annex A: Example of a METAR Report METAR EGLL Z 12003MPS 310V R09/P1500N R27/P1500U +SN BKN022 OVC050 M04/M07 Q1020 NOSIG 9949//91= METAR indicates that the following is a standard hourly observation. EGLL is the ICAO airport code for Heathrow Airport Z indicates the time of the observation. It is the day of the month (the 4th) followed by the time of day (1600 Zulu time, which equals 4:00 pm GMT) MPS indicates the wind direction is from 120 at a speed of 3 meters per second 310V290 indicates the wind direction is varying from 310 true (northwest) to 290 true 1400 indicates the prevailing visibility is 1,400 m (4,600 ft). R04/P1500N indicates the Runway Visual Range (RVR) along runway 09 is 1,500 m (4,900 ft) and not changing significantly. R22/P1500U indicates RVR along runway 27 is 1,500 m (4,900 ft) and rising. +SN indicates snow is falling at a heavy intensity. If any precipitation begins with a minus or plus (-/+), it's either light or heavy. BKN022 indicates a broken (over half the sky) cloud layer with its base at 2,200 ft (670 m) above ground level (AGL). The lowest "BKN" or "OVC" layer specifies the cloud ceiling. OVC050 indicates an unbroken cloud layer (overcast) with its base at 5,000 ft (1,500 m) above ground level. M04/M07 indicates the temperature is 4 C (25 F) and the dewpoint is 7 C (19 F). An M in front of the number indicates that the temperature/dew point is below zero (0) Celsius. Q1020 indicates the current altimeter setting (QNH) is 1,020 hectopascals (30.12 inches of Mercury) NOSIG is an example of a TREND forecast which is appended to METARs at stations while a forecaster is on watch. NOSIG means that no significant change is expected to the reported conditions within the next 2 hours. 9949//91 indicates the condition of the runway: o 99 indicates either a specific runway (e.g. 27 = Rwy 27 or 27L; adding 50 will indicate Right Runway) or all the airport's runways ("99"). Some locations will report the runway using 3 characters (e.g. 25L) o 4 means the runway is coated with dry snow o 9 means 51% to 100% of the runway is covered o // means the thickness of the coating was either not measurable or not affecting o usage of the runway 91 means the braking index is bad, in other words the tires have bad grip on the runway CAVOK is an abbreviation for Ceiling And Visibility OKay, indicating no cloud below 5,000 ft (1,500 m) or the highest minimum sector altitude and no cumulonimbus or towering cumulus at any level, a visibility of 10 km (6 mi) or more and no significant weather. = indicates the end of the METAR

47 Annex B: Diagrammatic Representation of Components of Example Wind Speed and Direction North 8.33 knots 6.66 knots 27R 5 knots 27L Direction of Landing A wind of magnitude 8.33 knots on a bearing of (say) can be resolved into two perpendicular components 5 knots at a bearing (i.e. due east) and 6.66 knots at a bearing of 000 (due north). The headwind experienced by the landing aircraft on 27L or 27 R is thus [8.33x cosine (53.1 degrees)] = 5 knots.

48 NATS Support to the Airports Commission Task 2.2c Developing Forward Strategy TASKING This briefing note responds to the action placed on NATS to: To undertake further work on this concept but with a focus on this concept to provide resilience, specifically advising on the airspace, ground and technology requirements to support the following three scenarios: (a) mixed mode for resilience during the current hours of operations (no planning cap increase); (b) mixed mode on a tactical basis i.e. when delay has reached more than 10 or 20 minutes like under operational freedoms; and (c) mixed mode for some parts of the day. Additionally, to advise what would be required to support a trial of mixed mode. i.e. would all the airspace changes be needed in advance? CONTEXT The concept of full Mixed Mode at Heathrow sees the simultaneous use of both runways (north and south) for departures and arrivals. The additional capability that such an operation would deliver would be realised through increased resilience and not though additional capacity (i.e. Heathrow would still be capped at 480k movements pa). However additional airspace capacity would be needed simply to maintain the same quality of service delivery due to the additional complexity that would be created (i.e. additional airspace capacity may be required to provide a more resilient service at the current capped levels) due to the additional operational complexity that would result. The concept would be used in conjunction with other planned developments at Heathrow, which are currently being delivered to increase the resilience of the operation, most notably the use of Time Based Separation on final approach to recover some of the reduced landing rates in wind conditions with a headwind component of greater than 5 knots. ICAO Document 9643 [1] sets out requirements for the Simultaneous Operations on Parallel or Near Parallel Instrument Runways (SOIR), including what precautions are necessary when the centre lines of such runways are separated by less than 1,525m. Such a separation (i.e. 1,525m) is the minimum runway separation for fully independent operations and anything less required additional mitigation or new regulations to fully utilise aircraft capability. The centre lines of the north and south runways at Heathrow are separated by c.1,410m, thereby precluding their use for simultaneous parallel operations without mitigating aspects being provided. SOIR rules currently dictate the requirement that NATS must adhere to with regard to two arrival streams. This levels some difficult challenges, technological and staffing, at NATS that make the timescales/cost/environmental impact almost prohibitive. When SRG were last approached around independent parallel approaches, their message was very clear that NATS must adhere to SOIR.

49 Engagement has begun to re visit this (and explore the use of RNP arrival streams) but this piece of work is in its infancy and there are no timescales or guarantees around this. The use of Mixed Mode without the requirements of SOIR being met would result in a sub optimal solution. Overall, delivering Mixed Mode operations, be it to increase capacity or improve resilience is complex and would require regulatory changes to make it permanent feature of the Heathrow operation. The benefits in terms of improved resilience would need to be weighed against the costs of its implementation. The outcomes of the recent Operational Freedoms trials concluded that the theoretical increase in resilience available from the use of both runways for arrivals was not realised, due to the complex manner in which departures had to be interleaved with arriving traffic and the knock on effect this had on balancing overall airport throughput. ASSUMPTIONS This analysis assumes that: 1. Time Based Separation will be deployed at Heathrow by spring 2015 (subject to Regulator approval) to sustain normal landing rates by reducing separation between vortex pairs under wind conditions with a headwind component of greater than 5 knots. Such a capability will make a contribution to providing resilient operations at Heathrow, thereby reducing somewhat the benefits that Mixed Mode would otherwise deliver to maintained the declared landing rate. 2. Mixed Mode to increase resilience does not require the use of independent parallel approaches but that the any such resilience can be maximised if such a capability was supported. 3. If independent parallel approaches or departures are indeed required to deliver the level of resilience required by this measure, then the requirements of ICAO Doc 9643 [1] will need to be fully complied with. This will require, inter alia, a system to monitor whether aircraft have departed from their final approach path and an additional Final Director positions (i.e. ATM facilities & controllers) to manage and monitor the traffic flows on each of the two runways. There is currently a shortage of Heathrow Approach controllers, and an additional Final Director would have a significant effect on the staff required, a situation which would take at least some three years to overcome (i.e. the time from recruitment to being able to provide the service unsupervised). This assessment makes no assumptions regarding: 1. The extent, if any, to which the Cranford Agreement would prevent or impair departures from Runway 09L; any such preventative issues are not down to the ability by NATS to provide safe and expeditious services. 2. Aircraft fleet mix or equipage, unless specific navigational capabilities are required (e.g. PRNAV) to adhere to any new SIDs and allied NPRs that may be required to maximise the resilience of airport operations by enabling simultaneous departures from both runways of flights are planning to route in a common direction.

50 OPERATIONAL CAPABILITY From an ATM service planning & delivery perspective, scenario c is a sub set of scenario a both would result in the strategic application of Mixed Mode at Heathrow at known times of the day. The timings and period of its use would be known by all stakeholders and may result in behavioural changes (such as arriving earlier on the expectation that holding will not occur) by operators. For brevity in this briefing note, scenarios a and c are termed the Strategic Application. Scenario b is different as it sees the tactical application of Mixed Mode, when pre determined triggers are reached, and is strongly aligned with the recent usage under the Operational Freedoms trials. This scenario is termed the Tactical Application. Such a distinction results in different impacts on the airspace, technological and ground issues associated with its development & use, as set out below. NATS has undertaken work in the past for BAA that set out a Concept of Operations for the use of Mixed Mode [2]. Whilst this was focused on increasing capacity, the key issues identified then are equally applicable to its use to provide (capacity capped) resilient operations. These are represented in Annex A. Airspace Considerations Strategic Application Additional complexity and additional controller workload would result from this type of application. The operation would need to be based around the concepts of: Terminal Arrivals where traffic lands on the runway most appropriate to its terminal building, which would increase complexity in the air as aircraft are routed to the appropriate stacks irrespective of whether they were arriving from the north or the south; and, Compass Departures where traffic would depart from the northerly runway if heading north or the southerly if heading south, leading to additional complexity in ground movements (e.g. a T4 departure taxiing to the 09L entry point). For the benefits of such operations to be realised, effective balancing of the holding stacks would be required, which may prove difficult if there was an imbalance in the predominant arrival flows and would have an impact on departures flows. Furthermore, such operations would be expected to have an adverse impact on NATS ability to offer Continuous Descent Approaches, with associated adverse noise and fuel/environmental impacts, as aircraft would either be descended earlier and flying lower over a great part of the arrival or held higher and descend later (both circumstances are less efficient that a CDA which NATS aims to provide).

51 NOT FOR OPERATIONAL USE Source: Partial screenshot of London Heathrow Compton 3F 3G 5J 4K, UK U AIP, AD 2 EGLL 6 1, 27 Jun 2013, Amendment 7/2013. Tactical Application The current airspace structure (in terms of SIDs and STARs and en routee sectorisation within London Terminal Control) would support the tactical application of mixed mode in a very limited way, similar to the Operational Freedoms trials [3].[ Although termed tactical, the impact on the operation and the co ordination required between the London Terminal Control and Heathrow Tower to transition into and out of Mixed Mode upon the triggering of predetermined delay (or other pre agreed) always carries a greater risk than maintaining an existing type t criteria should not n be underestimated. Changing how the service is delivered of operation, a risk mitigated by effective coordination across the various parties engaged in service delivery, yet adding complexity and temporarilyy increasing workload. From the perspective of the Heathrow Tower operation, it is currently not feasible to use Mixed Mode as a resilience measure that is switched on and switched off. Ensuring thatt the correct departures are at the correct runway requires a lot of planning this is made m more difficult by the GMC controller also having to fix all of the crossover issues for the arrival streams that cannot be fixed by TC. Heathrow Airport would also have to re visit their ground infrastructuree as the runway exits do not support a mixed mode operation. Technological Considerations Both the Strategic and Tactical applications havee common technologicall considerations and requirements. All possible arrival and departuree configurations are supported by Instrument Landing Systems (ILS), Microwave Landing Systems (MLS) and Precision Approach Path Indicator (PAPI).

52 If independent parallel approaches and departures are required to maximise the benefits of Mixed Mode, then Precision Remote Monitoring would be required to ensure aircraft do not deviate laterally from their approach path, either before or once established on the landing aid (ILS or MLS). Furthermore, a direct and immediate voice communications channel would need to be established between the two Final Director controllers at London TC (each one providing the final stage of the Approach Control service to the two runways) and the Heathrow Tower controller to ensure that deviations or go arounds are communications immediately once identified. Ground Considerations Any de confliction that did not, or could not due to complexity or workload issues (such as stackswapping), occur during the approach or landing phases by the en route function, would need to be managed on the ground by the Tower Ground Movement Controller/s. A balance would need to be struck between TC and Tower regarding which has the lead for this responsibility to ensure that the overall resilience of the operation is increased. In particular, careful consideration (potentially supported by real time simulations) would be required to assess the impact of increased ground control that would result from the concept of Terminal Arrivals and Compass Departures. As the ground holding points and taxiing facilities that support departures from 09L are not as well developed as the other three departing configurations (09R, 27L and 27R) because 09L has nor historically been used for departures, these would need to be enhanced to provide the maximise the ability to provide Tactically Enhanced Departures (TEDs) to avoid congestion at the entry point to the runway. Furthermore, turbulent conditions have been experienced on final approach to runway 27R when the surface wind is southerly. This condition is primarily caused by the British Airways wide body hangar. Whenever the surface wind direction is between and the speed in excess of 15kts, pilots are to be advised by the following message: "Turbulence may be experienced during the last mile of final approach to runway 27R". Such circumstances have in the past prevented landings on 27R and resulted in only 27L being used for landing. Such a situation would have an impact on the ability to use both runways for landing. SCHEDULING The Heathrow schedule is not built around a mixed mode operation that is, it is not balanced in terms of the direction of departures. As the airline businesses have developed to accommodate cheaper air travel, there are less and less domestic routes being flown out of Heathrow. This has resulted in a strong routing bias for southbound operations, meaning that mixed mode has even more limited value. In order to utilise mixed mode for resilience purposes, offload SIDs that allow southbound traffic to initially route North are more or less vital.

53 AIRSPACE CHANGES REQUIRED TO SUPPORT FURTHER TRIALS OF MIXED MODE Undertaking a trial of Mixed Mode operations at Heathrow would require a significant amount of effort to address the necessary airspace, safety assurance and ground based aspects. Such a trial could have an adverse impact on the effectiveness of existing operations if the balance between departures and arrivals on the two runways was not achieved, notably if the Terminal Arrivals and Compass Departures concept could not be effectively delivered, as is expected from the existing departure/arrival schedule. Airspace changes would need to be implemented, preceded by enabling public consultation and allied safety assurance process. Training controllers at both London Terminal Control and the Heathrow Tower would be required to ensure continued safe operations (potentially at the expense of efficiency). The implications on the efficiency of the overall operation from a network perspective would need to be fully understood before any such trial could occur. CLOSING REMARKS A greater focus on TEAM on and delivering to plan, with emphasis on making sure that TEAM landers are delivered into identified gaps on the departure runway, in a precise manner, is a much easier deliverable and supports resilience at Heathrow as well the overall business aspirations of the Heathrow Airport. Much work is being done, through the NATS led Heathrow Taskforce, around reduction in required regulation and more efficient use of TEAM, but precision delivery to plan, with a greater understanding of the upcoming schedules and the external drivers affecting the operation are likely to increase resilience, whilst supporting environmental targets, far better than Mixed Mode would be able to. REFERENCES 1. ICAO Document 9643, AN/941, Simultaneous Operations on Parallel or Near Parallel Instrument Runways 2. Heathrow Mixed Mode, Concept of Operations, Maximum Capacity (Baseline) Scenario, October Heathrow Operational Freedoms Trial Phase 1 Report, April 2012.

54 Annex A: Key Issues Raised During Development of Operational Concept for Mixed Mode. ARRIVALS TMA LTCC may require a revised operational strategy to limit the rate of LAM to BIG switches in any given hour. Failure to regulate LAM to BIG switches could cause particular difficulties for TMA SE and in particular TC BIG Sector. If Maximum Capacity (Baseline) Mixed Mode relies on the continuous switching of traffic between BNN & OCK, or OCK & BNN, this will be a key issue as it will increase complexity, and may lead to increased controller workload. RMA Westerly Operations Establishment of a Heathrow RMA 25nm east of Heathrow is complex. and as a minimum, traffic departing Gatwick on the LAM SID will need to be re routed prior to the expansion of the Heathrow RMA. Moving the Gatwick LAM SID east will not necessarily provide an immediate solution as this airspace is also heavily used by Thames Radar, and Luton/Stansted, for outbound traffic. Easterly Operations To the west of Heathrow. Heathrow RMA changes associated with joining altitudes of 4000ft/5000ft would require new airspace in the vicinity of Reading. This airspace change would require an ACP, with extensive consultation with both aviation and public representative stakeholders. Also, joining altitudes at and above 4000ft will require extensive work on Heathrow and Luton CPT SIDs. Realignment of the Luton CPT SID would require new airspace and this would also require an ACP with consultation as described above. The integration of Northolt arrivals with Heathrow Mixed Mode operations may cause difficulties within the Heathrow RMA. The routeing of Heathrow traffic to the correct holding facility for the intended landing runway will minimise RMA crossover and will aid the handling of Northolt arrivals but Northolt arrival restrictions may still need to be applied Final Approach Independent final approaches to parallel runways are not yet established in the UK. NATS will need to secure CAA approval to commence operations at Heathrow. Approval in principle is not considered to be an issue as specific guidance is provided in ICAO Doc Independent parallel approaches outside 10nm from touchdown require further research as ICAO indicates that the Total Navigation System Error (TNSE) increases with distance. ICAO Doc 9643, Appendix A contains an outline specification for a Precision Radar Monitor (PRM). PRM is not currently used in the UK, nor is it an absolute requirement for independent operations at Heathrow. With a runway spacing in excess of 1400m at Heathrow, NATS will need to evaluate the suitability of current radars against ICAO specifications for independent operations and a PRM type installation may be required. The safety case work associated with the installation of this type of equipment is complex and time consuming and may challenge project timescales. Although it is understood that CDAs will be less likely for traffic joining the ILS systems from the South, every attempt has been made to preserve CDAs when joining from the North, and they should be routinely available. The co ordination required between FIN directors during simulation indicates that traffic for both runways will need to join final approach at a significant distance outside the Glide path descent point. This will require a considerable period of level flight for traffic on the South runway.

55 During Independent Parallel Final Approach operations, the associated breakout procedure from runway 27R/09L will, in most cases, conflict with the Northolt Final Approach; therefore, Heathrow and Northolt traffic will need to be interleaved in order to maintain radar separation during breakout. On Easterlies, Heathrow 09L and Northolt arrivals will always conflict and will need to be interleaved. Any requirement to interleave (radar separate) Heathrow and Northolt arrivals has the potential to reduce capacity at one or both of the airports. It is likely that this capacity reduction will not be one for one as Heathrow traffic will normally operate a 6 mile spacing stream and Northolt traffic can be positioned between the Heathrow arrivals. The exact nature of the interleave arrangement will require further development which is outside the scope of this work. DEPARTURES The introduction of new P RNAV compliant SIDs would require major changes to the Heathrow NPRs and these changes will require extensive formal consultation. The proposed changes to TMA operating procedures in order to accommodate two CPT SIDs on westerly operations are challenging although changes to LACC airspace introduced in Summer 2006 should accommodate the proposed change at Swanwick The introduction of a 09L CPT departure delivers Westbound Heathrow traffic to the Henton (Luton) area and this traffic will need to be integrated with Luton departures. Indeed, it is unlikely that CPT 09L departures could be accommodated prior to the reorganisation of the TMA NW Departures sector. Every effort has been made to accommodate unrestricted departures at Northolt; however, some dependency is likely to remain when slow climbing Westerly Heathrow departures route via BPK. MISSED APPROACH PROCEDURES During work on Mixed Mode Missed Approach scenarios a basic solution to the interaction between Heathrow Missed Approaches and Northolt departures was established; however, detailed procedures will need simulator development and a comprehensive training programme for Heathrow controllers will be required prior to the commencement of operations. The exact modification required to the 09R Missed Approach has yet to be established. Should the 09R Missed Approach require a right turn then modifications to the 09R CPT radar SID will be required and this change may be subject to an ACP. HEATHROW GROUND MOVEMENT CONTROL Any increase in movement rate above the current schedule limit at Heathrow will depend directly on the provision of ground infrastructure to accommodate such an increase. Any increase in movement rate above the current schedule limit at Heathrow will require three GMC controllers. The New VCR at Heathrow makes provision for three GMC controllers. If development and simulation subsequent to approval identifies the need for additional GMC resource, NATS will need sufficient time to ensure that appropriately trained staff can be made available.

56 NATS Support to the Airports Commission Task 2.2c Developing Forward Strategy Tasking This briefing note responds to the action placed on NATS to: Advanced navigational capability and SIDS/STARS. To advise what NATS are doing to support a move towards more accurate navigational tracks and what benefits this is expected to derive i.e. will this support a move towards multiple approaches to a single runway and how will this work? The Airports Commission understand LGW are currently consulting on PRNAV SIDS, what are the benefits expected from this? LHR are also working towards this. NATS redesign of the London Terminal Manoeuvring Area (TMA) is being progressed by NATS London Airspace Management Programme (LAMP). LAMP sees a complete redesign of the arrival routes and departure routes for traffic operating in to and out of the five London airports. All the airspace designs planned to be developed and deployed by LAMP will be predicated upon aircraft supporting Precision Area Navigation (PRNAV) capability. Arrivals Arrivals will be based upon the concept of Point Merge at Gatwick, Stansted, Luton and City, and the concept of Tromboning at Heathrow (concepts which have previously been summarised and provided to the Airports Commission Secretariat). NATS has also undertaken a set of trials to deliver Environmentally Optimised RNP Arrivals (EORA), which assessed the viability of using Required Navigation performance (RNP) to support operations at Heathrow during TEAM operations. The outcomes of the trials will also be used to support arrival concepts that will be deployed by LAMP. Departures An early part of the LAMP is the Departures Enhancement Programme (DEP). This has been created as the first step towards systemisation of Terminal airspace and efficient use of Performance Based Navigation (PBN). This is a NATS led project that will simulate and develop revised departure routes in support of the LAMP. It intends to inform new national standards regarding reduced angles of divergence on departure and the placement of PBN routes against established holds. The project contains a programme of research, simulations and operational trials which will take place over the next two years. DEP is primarily a research project which is designed to inform large scale airspace projects including London Airspace Management Project (LAMP) and Northern Terminal Control Area (NTCA) (supporting the Manchester TMA) with regards to airspace procedures and safety assurance. Prior to LAMP delivering changes, DEP has been launched to perform trials and studies upon improved systematisation for Terminal Control operations. The findings of these trials and studies

57 will be used to inform new national standards regarding reduced angles of divergence for 1 minute departure intervals from a single runway, and the spacing of Performance Based Navigation (PBN) routes against established holds. The findings of these trials and studies will also be used in development of the LAMP Phase 2 airspace designs, which are due to be delivered into operational service for spring However, Gatwick Airport Limited is currently exploring opportunities to include a revised Standard Instrument Departure route to the south west of Gatwick that will overfly the Bognor Regis area (termed BOGNA) as part of LAMP Phase 1. DEP is scheduled to complete by December Key project activities and allied rational are: Thread Number DEP Thread Title Rationale 1 Deliver Heathrow Midhurst SID (Trial 1). In service of establishing the safe separation distance between the RNAV SID and a conventional hold, and gathering additional RNAV 1 track keeping data. 2 Develop 7 Heathrow SID quick wins which offer the airfield some small scale benefits through relatively minor SID changes and initial adoption of RNAV 1 standard completed July Generation of additional RNAV behaviour data which will provide evidence that supports DEP and other NATS projects such as LAMP and NTCA. 3 Deliver Gatwick BOGNA SID (Trial 1). In service of separation against conventional hold and operational trial of route placement in service of reduced departure separation. 4 Deliver a further iteration of the Heathrow Midhurst SID (Trial 2). 5 Deliver a further iteration of the Gatwick BOGNA SID (Trial 2). 6 Deliver a trial of a redesigned Heathrow Compton SID pair (Trial 1). 7 Deliver a further iteration of the Heathrow Compton SID pair (Trial 2). 8 Two iterations of a further SID trial (location TBD). 9 Deliver a RNAV Holding trial including RNAV STARS replication Refining the previous design following Trial 1, in service of establishing the safe separation distance between the RNAV SID and a conventional hold, and gathering additional RNAV track keeping data. Refining the previous design following Trial 1, in service of establishing the safe separation distance between the RNAV SID and a conventional hold, and gathering additional RNAV track keeping data. In service of proving reduced departure splits, parallel offload departure routes and resolving Compton hotspot. Refining the previous design following Trial 1, in service of proving reduced departure splits, parallel offload departure routes and resolving Compton hotspot. In service of 1 minute departure splits following the same initial turn from a single runway operation. In service of improved containment and MET resilience of holding aircraft

58 All activities align with, and to a certain extent are driving, the expectations of the CAA s Future Airspace Strategy (FAS). The LAMP summary business case is attached to this briefing note. This sets out the costs, benefits, timescales and strategic context of this development. The airspace designs being developed and simulated are based upon the existing types of operation currently provided (e.g. segregated mode at Heathrow) and the existing number and location of runways used by the five London Airports. Public consultations on the early aspects of the airspace redesign are scheduled to start on 15 th October.

59 NATS Support to the Airports Commission Task 2.2c Developing Forward Strategy Tasking This briefing note responds to the action placed on NATS to: Provide the milestones being worked towards to deliver the following options including whether there are any key dependencies or risks to delivery (and the likelihood of them materialising if possible): Queue Management AMAN, DMAN and XMAN. Time Based Separation. LAMP including the Departures Efficiency Project aspect. Queue Management Target Delivery: Queue Management (QM) is a programme of work that will deliver various systems into the operation to reduce airborne and ground-based holding. Each aspect will be delivered by specific projects delivering benefit in their own right. QM seeks to apply more accurate data and integrated tool support to sequence arrival and departure flows, presenting inbound traffic to the terminal environment in an optimal order, on time and on schedule; and de-conflicting outbound traffic from multiple airports. It will deliver Time-Based Separation (TBS)(see below), Departure Management (DMAN), Time-Based Flow Management (TBFM) and Extended Arrival Management (XMAN) tools into the operation. The programme will deliver over the five year period of RP2 ( ). Key Dependencies: Most aspects of this can be delivered through managing project & programme dependencies internal to NATS, except TBS (see below). The effective use of TBFM and XMAN depends upon the cooperation of neighbouring Control Centres to apply the speed adjustments required to ensure optimal arrival time at the airport holding stack. Such requirements are addressed through bi-lateral reviews. Risk to Delivery: Low most aspects managed within NATS. Funding is provisioned in NERL s RP2 Business Plan but will need to be approved by the CAA.

60 Time Based Separation Target Delivery: Key Dependencies: 2015, initially at Heathrow. A subsequent deployment at Gatwick is envisaged but not yet scheduled. Approval by CAA Safety & Airspace Regulation that TBS operations will provide tolerably safe operations as demonstrated in the Project Four Part Safety Case and Unit Safety Case as required by the NATS Safety Management System. The safety case will be based upon evidence derived from analysis of the dissipation of wake vortex air disturbance and its impact on following aircraft. Risk to Delivery: Medium. This is a major change to current operations and will require sufficient evidence to be gathered, thoroughly analysed and correspondingly robust arguments made to the safety regulator. It will deliver the first instance in the world of such operations and is following aggressive timescales. The Met Tool used by the TBA application will need to be validated, as it will use weather information downlinked from aircraft which will require electronic validation before operational use. LAMP Target Delivery: Key Dependencies: Phased, delivering in two phases. Phase 1, delivering airspace changes using the current TA and enablers which are compatible with Phase 2, will deliver in stages from mid-2015 until early Phase 2 will deliver the core changes to the London TMA supporting a raised TA in winter 2017/18 until completion in Full delivery of this investment depends upon: The Transition Altitude being raised in the UK. The UK supports such a level and is supporting the harmonisation of the TA across Europe to achieve this outcome. The ability of aircraft to support the level of navigation accuracy required to support the revised route network structure. The Airspace Consultation, as required by the UK CAA, providing the necessary approvals to deploy the revised airspace structures. In particular, approval will be required to deliver the revised departure routes from the London airports affected by LAMP currently being simulated by the Departures Enhancement Project (DEPs). Risk to Delivery: Medium this investment will result in a major redesign to the London TMA and will require a positive outcome from significant public consultation. NATS is actively managing the public consultation to ensure that the beneficial outcomes of the revised airspace structures are understood by all stakeholders.

61 NATS Support to the Airports Commission Task 2.2c Developing Forward Strategy Tasking This briefing note responds to the action placed on NATS to: Multiple Arrival Routes for Respite. LGW already offer respite for communities under the arrival NPRs. It would be helpful to understand more about how NATS do this and also how applicable this would be to other airports, most notably Heathrow. Does this hinge on aircraft having more advanced navigational capability like PRNAV? The tracks inbound to Gatwick are from the south only and they land fewer aircraft than Heathrow with far fewer inbounds being separated by minimum radar separation. Consequently it is easier to define a single track that aircraft could follow inbound to Gatwick, and there are greater opportunities for controllers to move the route for noise respite. At Heathrow there are stacks North and South, in order to maintain a high landing rate, controllers need flexibility to vector aircraft and consequently the swathe of aircraft tracks into Heathrow is much greater. To develop a track that could be altered for noise respite at Heathrow would give controllers far less flexibility and be severely detrimental to throughput.

62 EVOLVING AIR TRAFFIC OPERATIONS: A LOOK INTO THE FUTURE Context Air Traffic Management will change significantly over the next 10 years, with constraints that limit the effectiveness of today s operation largely overcome by advances in ground based and airborne technology. This will result in changes across all aspect of the ATM service delivery chain, providing positive benefits to airline operators, airport operators and passengers. All aspects of the services provided by NATS will evolve to provide more efficient services, allowing NATS customers to benefit from and better exploit the sharing of accurate and up to date flight information across all phases of flight. This paper sets out how the service NATS provides will be different in the future (taken to be c.2025); what benefits such differences will bring to airline and airport operators alike; and, what external factors are outside NATS control which may prevent the capabilities of the future operation being fully realised. Strategic Scheduling Effective service delivery is underpinned by effective planning and which considers the capabilities of all aspects of the ATM network in a more strategic manner than is possible today. An important aspect to consider is that this will start months in advance of take off as the airline operator considers what s best for their business in terms of destination and routing and how an individual flight best fits within their overall scheduling model. The ability of operators to promulgate an achievable schedule to service providers will enable effective delivery planning to occur by all stakeholders. Across all users, this will result in a network plan that reflects the desires of all users of the airspace and to which all affected service providers must respond. Greater certainty of future demand across the network will allow all actors within the service delivery chain to reflect the type and level of services required. From an ATM service delivery viewpoint, such a greater reliance on strategic planning will enable greater consideration of staffing levels and capabilities to ensure that the right resources are available on the day, to deliver the optimum ATM service. Whereas today s operations are more aligned to the tactical use of airport and operator resource planning in the short term, the use of Airport Collaborative Decision Making (ACDM) systems will allow all subscribers to access more accurate, wide ranging and timely information pertinent to specific flights. NATS is working with the owners of both Heathrow and Gatwick airports to

63 develop new systems that will deliver ACDM operations, both tactically to support specific airport operations and strategically to ensure that Departure Management (DMAN) systems are able to fully exploit the latest information about departing traffic. Departure Management Today s operations in the south east of England are determined by the quantity, location and orientation of the runways are the London airports. The airspace structure that provides the departure paths from the various runway locations & orientations provides a highly complex web of routes that effectively connect the airports to the en route airspace infrastructure. Departures are systemised to a large extent through the use of Standard Instrument Departures (SIDs), which are 3 Dimensional routes that set out specific point and heights from take off that an aircraft navigates to route it towards its ultimate destination. The rate at which aircraft can depart from a particular runway is limited by several factors to ensure safe operations. An aircraft departing from the same runway as the one ahead has to be a safe distance behind to ensure that minimum separation standards are maintained. Such situations are addressed today by ensuring that if the following aircraft will diverge in direction by less than 45 degrees from the one ahead, then the following aircraft will not take off less than 2 minutes after the one ahead, otherwise a 1 minute criteria is applied. Such a situation limits the runway s take off capacity, and thus the capability of the airports as a whole. NATS is planning to reduce the 2 minutes divergence angle from 45 degrees to a lesser value, potentially as low as 15 degrees. This would reduce the instances where 2 minute departures are required, thereby increasing departure capacity. The establishment of new SIDs is a complex process as their interaction with existing SIDs and the impact they would have on the en route airspace structure needs to be modelled. Furthermore, their establishment would be subject to the CAA s Airspace Change Process, with the environmental impact being subject to public consultation. Government policy is to concentrate noise over defined and narrow noise swaths & ground footprints. Such operations will be supported by aircraft supporting Performance Based Navigation (PBN), which sees airborne systems being far more capable in flying with greater accuracy the intended flight path. The importance of PBN capability is acknowledged across the industry, with plans in place to mandate such a capability via Implementing Rule across Europe by December 2020, with the potential for local or regional implementations earlier. Such improvements also support service

64 delivery, with greater certainty of the ability of aircraft to better adhere to the centre line of the intended flight path increasing the capacity of the airspace. Arrival Management Effective airport operations are created through effective departure and arrival operations, considering all aspects of the arrival, turn around and departure phases. Similar to the concept of SIDs to maximise the effectiveness of departures, Standard Terminal Arrival Routes (STARs) exist to provide an effect flow of traffic to the destination airport. Like SIDs, STARs form an integral part of the operation and their changes/relocation are subject to airspace change analysis to assess the impact change would have on the operation and those effective be revised noise & visual impact. Airborne Holding is a key feature of today s operation, which sees the use of tiered orbital tracks which aircraft fly around when the demand on arrival runways exceeds capacity. Such operations are both inefficient for service delivery as they require controller monitoring/intervention and fuel inefficient for operators. NATS continues to develop its Arrival Manager (AMAN) system to provide controllers with more accurate information about aircraft arrival time at the holding stack entry points, with the intent to revise the speed of the aircraft (within acceptable limits) to reduce or even avoid the need for airborne holding, termed Linear Holding. AMAN forms a key part of effective Queue Management, explained later in this brief. Further developments are in hand to deliver improvements to this phase of flight through revised airspace and route networks that (by design) reduce or avoid where possible the need for downstream queuing through the more predictable presentation of traffic, supported by concepts that aim to deliver for efficient queuing if required through linear holding and Point Merge and Tomboning concepts. Point Merge is an innovative method developed by the EUROCONTROL Experimental Centre (EEC) for merging arrival flows with existing technology including precision area navigation (P RNAV). It is designed to enable extensive use of the flight management system and continuous descents, even under high traffic load). The concept is already used by the Irish Aviation Authority (IAA) to support air traffic operating within the Dublin TMA. NATS is adopting Point Merge concepts as part of its on going redesign of the London Terminal Manoeuvring Area (TMA) being undertaken by the London Airspace Management Programme (LAMP) investment, which has been established to provide a complete redesign of the London TMA to provide more efficient operations to all the airports in a manner that reflects progressive advances in aircraft capabilities (both avionics and performance) and addresses forecast future demand. Point

65 Merge will be used in conjunction with (revised) Standard Terminal Arrival Routes to reduce the need for airborne holding in holding stacks. In effect, Point Merge sees the management of arrival streams on arcs from a common point (the merge point ) rather than utilising holding stacks, thereby providing environmental, safety and efficiency benefits. Such concepts fully accord with the CAA s Future Airspace Strategy (FAS) and the advanced concepts envisaged by SESAR for Terminal operations. LAMP will deliver Point Merge arrival concepts to Gatwick, Stansted, Luton and London City airports. The concept of Point merge is illustrated below. Figure 1: Example of Use of Point Merge Due to the complexity of the airspace supporting Heathrow, this will use the different arrival concept of Tromboning. Trials are on going and the ultimate concept subject to further simulation, but envisage traffic arriving at Heathrow flying descending routes parallel to the runway before being turned by the controller to intercept and establish on the Instrument Landing System at various distances from touchdown, depending on the density of arrival flows (as illustrated below).

66 Figure 2: Example of Use of Tromboning at Heathrow The use of Tactically Enhanced Arrivals Mode (TEAM) will continue to be used at Heathrow to enable landing on both runways under certain circumstances to reduce the need for airborne holding. Queue Management Getting the balance right between arrival and departure flows is a key determinant in effective airport operations, with aspects of the operation that have a direct impact on one having a knock on impact on the other (e.g. if an aircraft lands late, due to scheduling that maximises aircraft utilisation, there will be an increased likelihood that it will depart late). An imbalance results in congestion the most visible part of operational inefficiency at airports. Even the smallest delays in the system can have a dramatic knock on effect, leading to departure delays, missed slots and ultimately cancelled flights. By 2020, with better scheduling available within the industry, accurate data and integrated runway management tools, NATS will optimise the use of runways and airspace through strategic and/or tactical intervention at the most efficient points of an intended or active flight; effective Queue Management is the key to achieving this aim. NATS has established a specific Queue Management programme with the specific intents to: Optimise runway utilisation for single airports and TMA airport groups. Optimising available runway capacity is at the heart of NATS Strategy and is of particular importance given the lack of plans to build additional runways in the South East of England; Reduce stack holding in terminal airspace. If it is possible to do so, the elimination of stack holding in terminal airspace would improve safety and environmental performance whilst increasing the availability of airspace for Continuous Climb and Descent Operations; and,

67 Enable free flow departures for terminal airports. At a simple level, all airfields generating traffic operating under Instrument Flight Rules (as opposed to operating visually) should be electronically linked into the network; and should provide Departure Planning Information (or equivalent message) to the network. This will apply to any airfields within the AMAN metering horizon which are feeding traffic into an arrival stream. The concept of Queue Management exists to reduce (and, aspirationally, eliminate) the need for queuing with resultant adverse impact on airline operations when demand exceeds capacity, which predominantly occurs during the preparation of the landing phase of flight when airport landing capacity cannot support imminent demand. Whilst the throughput of serial process system can be maximised by absorbing demand by queuing 1, in air traffic operations this results either airborne or ground holding, with varying primary (fuel and delay) impacts and secondary (scheduling) impacts. NATS Queue Management programme comprises the coordinated development of a set of related investments to deliver operational improvements in this area to cover the various phases of flight that comprise the arrival and departure service delivery chain. The concept is wider than just Arrival Queue Management: NATS investments seek to deliver a holistic approach to arrival/departure service delivery so that a more balanced type of operation is provided without the need to hold/queue (and therefore penalise) either the arriving or departing traffic flows. The diagram below sets out how these concepts together provide a more efficient operation. 1 For example, the Heathrow schedule is designed not to exceed 10 minutes average airborne holding.

68 Figure 3: Illustration of Cross ANSP Departure & Arrival Management Currently the Queue Management programme is engaged with airline operators and the CAA through the Future Airspace Strategy initiative in order to progress this issue. With the co operation of stakeholders, NATS intends to ensure operators towards better scheduling and schedule adherence (generally known as Arrive on Time) by By end 2015, NATS intends to receive and act upon A CDM departure data from Heathrow and Gatwick. Between 2015 and 2020 the implementation of Runway Mangers (a tool that will integrate AMAN and DMAN systems) at Heathrow and Gatwick in conjunction with TBS will enhance traffic synchronisation significantly within the London TMA. A key aspect of the Queue Management programme is to deliver Time Based Separation (TBS) on Final Approach to sustain planned landing rates during headwind conditions. The first deployment will occur at Heathrow where, due to exceptionally great runway occupancy rates of c.98%, the impact of a reduction in landing rates, has a significantly adverse impact on airport operations. Heathrow Airport currently operates to Distance Based Separation (DBS) separation criteria during the final approach phase of flight to 4NM from airport Distance Measuring Equipment (4DME). Speed restrictions are applied on final approach meaning that during periods of medium and strong headwinds the ground speed of arrival aircraft slows and the time between successive arrivals increases. This can result in a significant drop in the landing rate