Table of Contents Foreword by the Managing Director... 4 1. Introduction... 5 2. Why are we proposing this airspace change?... 5 3. Change Options... 8 4. Trials... 12 5. Future Use of Required Navigation Performance (RNP1) SIDs... 12 6. Airspace Description of Proposed RNAV1 SID and NPR Swathe Reduction... 13 7. Airspace and Infrastructure Requirements... 14 8. Operational Impacts... 14 Overview of Current Operations... 14 Trial Results... 15 9. Environmental Impacts... 21 Noise... 21 Population Overflown... 26 Fuel Burn and CO 2 Emissions... 29 Local Air Quality... 30 Tranquility and Visual Intrusion... 30 10. Consultation Process... 33 Consultation Feedback... 33 Airspace Change Proposal and Implementation... 33 List of Appendices... 35 Page 2 of 59
Glossary Acronym Definition AIP UK Integrated Aeronautical Information Package ATC Air Traffic Control ACP Airspace Change Proposal AONB Area of Outstanding Natural Beauty CAA Civil Aviation Authority CAP 725 Civil Aviation Publication 725 FLOPC Flight Operations Committee INM Integrated Noise Model KIAS Knots Indicated Air Speed LLACC London Luton Airport Consultative Committee NATS National Air Traffic Services NM Nautical Miles NPR Noise Preferential Route NTSC Noise and Track Sub Committee QNH Barometric pressure adjusted to sea level RNAV1 Area Navigation (GPS based aircraft navigation technology) RNP1 RF Required Navigation Performance Radius to Fix SARG Safety and Airspace Regulation Group SID Standard Instrument Departure Page 3 of 59
Foreword by the Managing Director For 75 years the Airport has been an important landmark in Luton and has played a major part in the lives of many local people. Since the mid 1990s in particular the Airport has grown rapidly and is now the fifth largest and among the fastest growing in the UK. It is also the single largest centre of employment in the area and contributes over 8,000 direct jobs and nearly 1 billion to our region each year. We believe that this success has been built and is sustainably maintained on a foundation of strong relationships between the Airport and its communities. It is essential that the Airport continues to bring significant economic benefits to the region whilst at the same time mitigating the environmental impacts of a thriving airport. We recognise at the local level, the main issue is noise disturbance. In order to preserve the balance between a vibrant, growing airport and the need to protect our local communities from excessive aircraft noise, we have developed a robust set of measures which form the Airport s Government approved 55 point Noise Action Plan. As part of our commitment to our neighbours we continually look for ways in which we can reduce the impact of the Airport. The recent introduction of GPS based aircraft navigation technology known as Area Navigation (RNAV1) is a unique opportunity to do just this. Through enabling flight routes to be flown consistently more accurately, and by giving greater flexibility in their design, we are able to route flight tracks to avoid centres of population wherever possible, thereby potentially reducing the number of people disturbed by aircraft noise and through more efficient routeing of aircraft, reduce airborne emissions. This consultation offers the opportunity to introduce such technology and improve track keeping on one particular route, however the Airport views this as the first phase of introducing RNAV1 technology on all departure and arrival routings. Thank you for taking the time to read this consultation. We welcome your feedback on these proposals. Glyn Jones (Managing Director) Page 4 of 59
1. Introduction The purpose of this consultation document is to describe our proposal to introduce Area Navigation (RNAV1) technology for departures leaving London Luton Airport to the West along the Clacton/Dover/Detling flight routes, and to invite feedback from stakeholders. Aircraft using these routes depart from Runway 26 (which is the runway in use when the wind is from a westerly direction) and all follow the same route until they reach a reporting point known as the Brookmans Park beacon where they diverge towards Clacton, Dover or Detling. For the purposes of this consultation they shall be referred to as Runway 26 Brookmans Park (BPK) departures. This document explains: Current track-keeping issues Details of the options considered to improve track-keeping The proposed RNAV1 Standard Instrument Departure (SID) The results of trials conducted to investigate each option, outlining the operational and environmental benefits and impacts of introducing an RNAV1 SID. Next steps and how to respond to this consultation. This document and its appendices have been prepared following the requirements set out by the Civil Aviation Authority (CAA) in its publication CAP725: CAA Guidance on the Application of the Airspace Change Process. The consultation period will run from 10 th April 2014 to 9 th July 2014. The options being consulted on are consistent with London Luton Airport s Noise Action Plan, a copy of which can be found at this link. Should any problems be experienced with viewing the text or detail in any figure, please zoom in to enlarge the diagrams or contact London Luton Airport Operations Ltd for an enlarged copy using the contact details in Appendix A. 2. Why are we proposing this airspace change? For over 10 years the Airport has been working with airlines, NATS, our Air Traffic Control provider (ATC) and the CAA to look at ways track-keeping can be improved on the Runway 26 BPK departure route. Upon departure from the Airport, aircraft follow flightpaths within defined Noise Preferential Route (NPR) corridors. These routes are established to minimise the number of people overflown, and from London Luton Airport the NPR corridors currently extend 1.5km either side of the nominal SID centreline (nominal track). Aircraft are required to remain within the NPR swathe until they reach an altitude of 3,000ft during the daytime or 4,000ft at night, after which time ATC may vector aircraft onto a more direct heading towards their final destination, based on other air traffic in the area at the time. As can be seen from Figure 1 the actual flightpaths being flown deviate sometimes from the theoretical route that is detailed in the SID. This results in aircraft sometimes passing outside of the NPR corridor and overflying the densely populated northern parts of Hemel Hempstead and St. Albans. Sample flight tracks for a typical 24 hr period are provided in Figure 2. Page 5 of 59
Legend: Current route actual (average) Current SID centreline Current NPR Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 1. Current theoretical SID centreline and actual average flight paths Page 6 of 59
Legend: Current departure flight tracks Current SID centreline Current NPR Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 2. Current sample flight tracks in relation to the existing NPR Page 7 of 59
Runway 26 BPK departure routes are in use during westerly operations which occur approximately 70% of the time and facilitate approximately 40% of all departing aircraft when in operation. These percentages are based on an average of statistics from the last five years and equate to approximately 60-70 flights per day for 70% of the year (based on 2013 total aircraft movements). In 2011 the Airport conducted a trial involving 10 easyjet departures per day on the 26 BPK departure routes that reduced the speed of aircraft in order to help them fly closer to the nominal track. This trial was successful in terms of track-keeping within the existing NPR swathe, but resulted in communities such as Flamstead and Redbourn being overflown by more aircraft. The introduction of RNAV1 technology would enable a route to be designed (within the tolerances of RNAV1 criteria) that avoids centres of population. The objective of this proposal is therefore to implement a new RNAV1 SID, for which the nominal route tracks between Markyate and Flamstead, Redbourn and Hemel Hempstead, as well as St. Albans and Harpenden but still remains within the current NPR corridor. 3. Change Options This section details the various options available to implement an RNAV1 based version of the SID for Runway 26 BPK departures, for use in parallel with existing conventional navigation based SIDs for aircraft unable to utilise this technology (which currently stands at approximately 10% of all aircraft). In addition, this proposal highlights options if RNAV1 technology was not implemented as a result of this Airspace Change Proposal (ACP). Option 1: Do nothing This option is to keep to the current route procedures being undertaken at London Luton Airport which have been flown for a number of years using conventional navigation technology. As can be seen in Figure 2, aircraft deviate from the nominal track which results in aircraft overflying north Hemel Hempstead and St Albans and thereby causing increased noise disturbance in those areas. This also results in track dispersion beyond the existing NPR corridor. Option 2: Reduce aircraft speed and make minor adjustments to aircraft turn points Option 2 is based upon a trial conducted by London Luton Airport in conjunction with easyjet, between 5 th May 2011 and 6 th November 2011 on the Runway 26 BPK departure route. Following feedback from communities over a number of years concerning aircraft deviating outside of the NPR corridor in the vicinity of Hemel Hempstead/St. Albans the Airport worked closely with airlines, the CAA and ATC to look at ways to help improve track-keeping on this route. It was determined that by reducing the speed of aircraft from 230-250 knots 1 to 220 knots on the second turn to the east and initiating the turn point around 1 nautical mile (NM) earlier, aircraft followed the nominal track much closer. Figure 3 illustrates a sample of typical flight tracks during the trial, along with the current NPR corridor and SID. In terms of achieving the objective of flying within the NPR corridor the trial was successful, with the majority of aircraft flying closer to the nominal track. However following extensive community feedback it became apparent that the nominal track was not necessarily in the best place anymore to avoid centres of population, particularly in relation to Redbourn. With conventional navigation techniques very little else could be changed to modify the route any further. 1. Please note that where knots has been used throughout this document, this refers to Knots Indicated Air Speed (KIAS) Page 8 of 59
Legend: easyjet trial flight tracks Current SID centreline Current NPR Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 3. Sample flight tracks from the easyjet trial in 2011 Page 9 of 59
Option 3: Adopt a new RNAV1 SID with an initial speed restriction of 210 knots. In order to mitigate the negative effects of the trial held in 2011 (option 2) it was clear that a more precise form of track-keeping was required to get aircraft to fly closer to the nominal track and to enable modification of the nominal track so that it avoids the most densely populated areas along the route. An RNAV1 based version of the SID departure routes for Runway 26 BPK departures has therefore been considered as option 3, with an initial speed restriction of 210 knots for use in parallel with existing conventional navigation based SIDs for those aircraft not able to utilise RNAV1 technology (estimated to be under 10%). Figure 4 illustrates the SID departure route for option 3, and NPR swathe using the RNAV1 procedures. The route shown in Figure 4 was designed to avoid communities such as Markyate, Flamstead, Hemel Hempstead, Redbourn, St. Albans and Harpenden, and is based on a 2km swathe. This is a narrowing of the NPR corridor by 0.5km either side of the nominal track, which is proposed to be implemented following a period of familiarisation as RNAV1 technology will enable aircraft to follow the nominal track much more closely than using current navigation methods. The daytime vectoring altitude would also be raised from 3,000 ft to 4,000 ft to ensure aircraft fly within the swathe for longer, bringing it in line with the night-time vectoring altitude. Furthermore, above 4,000 ft, aircraft will be routinely kept within the NPR corridor until crossing the railway line between St. Albans and Harpenden, however this will be at the discretion of ATC, as tactical vectoring may be required for safety reasons such as other air traffic or weather systems in the area at the time. Option 4: Adopt a new RNAV1 SID with an initial speed restriction of 220 knots. It was noted during consultation with airlines represented on the Airport s Flight Operations Committee, that at 210 knots aircraft generally have to fly with the flaps extended which can increase airframe noise, use more fuel and put aircraft in an awkward configuration. At a slightly higher speed of 220 knots aircraft could avoid this configuration and fly the route more efficiently. Option 4 was therefore developed following this feedback. A route was developed with a similar NPR to option 3, but with a slight refinement on the speed of the second turn to bring it up to 220 knots. This RNAV1 based version of the SID departure routes for Runway 26 BPK departures was again developed for use in parallel with existing conventional navigation based SIDs for aircraft unable to utilise the RNAV1 technology. The same restrictions as option 3 would also be put in place with regards to swathe width and vectoring procedures as shown in Figure 4. Page 10 of 59
Legend: RNAV1 SID RNAV1 NPR Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 4. RNAV1 SID and NPR corridor with a 2km swathe Page 11 of 59
4. Trials Options 3 and 4 were initially tested in a flight simulator to prove flyability. It was then agreed with the CAA and ATC that a short trial could be flown for both options. The aim of this trial was to to find out if noise impacts lessened or increased, and if track-keeping improved or deteriorated with the change in speed. The trial for Option 3 (210 knots) commenced on 7 th March and ran to 18 th April 2013. The second trial (220 knots) took place from 19 th April 2013 until 24 th May 2013. Due to an unusually high percentage of easterly operations during the initial 210 knots trial, a further 4 week extension to the option 3 trial was agreed to take place between 25 th May and 22 nd June 2013. The operational impacts of each trial are presented in Section 8, including plot densities of flight tracks. An environmental analysis of the results for both trials, incorporating an extensive noise monitoring programme in six locations along the trial route, is also shown in Section 9. Following detailed analysis of the results of the trials it has been concluded that environmental benefits would occur as a result of the adoption of an RNAV1 SID. Whilst airline representatives on the Flight Operations Committee expressed preference for adoption of an RNAV1 SID with an initial speed restriction of 220 knots (Option 4), the environmental evidence does not favour this option above the RNAV SID 210 knots (Option 3). The results of the trial suggest the environmental benefit with regards to noise would be slightly greater with the adoption of Option 3, however this could be due to other factors such as weather. It was therefore decided to put both ACP Options 3 and 4 forward for consultation. Stakeholders are invited to comment on these options, and feed back any observations regarding compliance with the consultation process as set out in CAA s guidelines for airspace change (CAP725). Full details on how to provide feedback is provided in Appendix A. 5. Future Use of Required Navigation Performance (RNP1) SIDs A further enhancement of performance-based navigation capabilities is due later this year when new SID design criteria is expected to be approved by the International Civil Aviation Organisation (ICAO), and by the CAA for use in the UK. This will involve the introduction of a new design criterion for Required Navigation Performance (RNP1) SIDs which will incorporate designs with path terminators known as Radius to Fix (RF). The technicalities involving this criterion are beyond the scope of this consultation; however aircraft flying SIDs using RNP1 RF capabilities are expected to achieve even more precise track-keeping in order to follow the nominal track. This would further enhance track-keeping, particularly through the turns in the event of strong winds through the use of auto-correction, and result in a reduced swathe compared with that achieved by aircraft following RNAV1 procedures. Therefore, if a BPK RNAV1 SID proposal is approved by the CAA, and following successful implementation, additional design and analysis will assess the feasibility of implementing an RNP1 RF SID on this route and potentially other SID routings from Luton. In this eventuality, appropriate consultation will be conducted. Page 12 of 59
6. Airspace Description of Proposed RNAV1 SID and NPR Swathe Reduction In the event that an RNAV1 SID is adopted, it would be a SID within existing Class D controlled airspace for Runway 26 Clacton, Dover and Detling departures. The SID would broadly be a replication of the existing conventional SID and wholly contained within the existing NPR corridor. The width of the current NPR swathe is 3 km (1.5km either side of the SID centreline) and it is proposed that following a period of familiarisation, the swathe width would be reduced from 3 km to 2 km for aircraft flying the new RNAV1 SID. The familiarisation period will be a maximum of 6 months. If an RNAV1 route is adopted and the swathe reduced, the vast majority of Flamstead and Redbourn would no longer be within the NPR corridor. The RNAV1 NPR would pass slightly further west at the second turn and pass between Redbourn and Hemel Hempstead. It was identified during the trial that whilst the majority of aircraft maintain a much tighter track swathe than using current navigation techniques, high winds can cause slight deviations particularly through the second turn. A 2km swathe is therefore considered appropriate at this time, but will be reviewed and possibly reduced further when RNP1 RF is considered. The daytime vectoring altitude would also be raised from 3,000 ft to 4,000 ft to ensure aircraft fly within the swathe for longer. Whilst ATC will still be permitted to tactically vector aircraft (i.e. given a specific heading towards their final destination) for safety reasons, aircraft will generally track within the swathe until crossing the railway line between St. Albans and Harpenden. The RNAV1 NPR (Figure 4) is therefore illustrated as stretching further east than the current NPR (Figure 2) that currently terminates soon after passing Redbourn. The night time vectoring altitude will be maintained at 4,000 ft, and similarly aircraft will only be tactically vectored at night once they have passed the railway line. Track-keeping of all Luton aircraft movements is currently monitored on a 24 hours basis to ensure flight crews adhere to standard recommended procedures. The Aircraft Noise and Track Monitoring system automatically provides notification of any track deviations outside the NPR corridor below the vectoring altitude, enabling action to be taken up with airlines quickly if published procedures are not being followed. In the event that RNAV1 procedures are adopted along the Runway 26 BPK departure route, and following a period of familiarisation, where clear track-keeping infringements occur (i.e. not safety or weather related) then a penalty system would be introduced in conjunction with our Flight Operations Committee and London Luton Airport Consultative Committee (LLACC). Due to variance in aircraft performance and different types of on board aircraft flight management systems, stakeholders should note that aircraft may not precisely follow the designed nominal track of an RNAV1 SID departure route during turns and there may be very slight differences in the track flown; this can also vary due to a number of different meteorological conditions (such as strong winds), aircraft loading and climb performance factors. There is therefore potential for aircraft to be displaced either side of the designed nominal track during a turn particularly in extreme adverse conditions, so stakeholders should not be surprised to see some aircraft occasionally fly on the extreme parameters of the NPR swathes or possibly outside the lateral limits in extreme circumstances. The track achieved over the ground during the operational RNAV1 trials is shown in Figures 6 to 9, which provide a good illustration of the track keeping which may be achieved. The hours of operation will remain unchanged, and if RNAV1 is introduced this will not increase or decrease aircraft capacity along this route or any other route. Page 13 of 59
The conventional SIDs for Clacton, Dover and Detling will be retained for non-rnav1 equipped aircraft. Aircraft must be certified as having appropriate navigation systems on board to fly RNAV1 procedures, and be approved by the relevant authorities of the state that the aircraft are registered in to fly the procedures. Additionally flight crews have to complete appropriate RNAV1 training and be approved by the appropriate state authorities to conduct RNAV1 operations. Therefore, in the event that RNAV1 is adopted along this route, two NPR swathes will be in operation: One for the conventional SIDs, and one for the RNAV1 SIDs. NATS propose to remove the Dover SID on 29 th May 2014, and replace this with the existing Detling SID to enable more accurate fuel planning. Whilst the details regarding this change are outside the scope of this document, it is important to note that this change will not alter aircraft flight tracks over the ground either vertically or laterally in the vicinity of London Luton Airport, and does not affect the validity of the results from the trials. 7. Airspace and Infrastructure Requirements Following the RNAV1 trial, ATC have demonstrated that the processes, procedures and infrastructure are already in place to introduce the RNAV1 SID on a permanent basis. As RNAV1 is aircraft based navigation rather than ground based there is no impact on ATC equipment. The proposed AIP chart is included in Appendix B. 8. Operational Impacts Overview of Current Operations Runway 26 BPK departure routes are in use during westerly operations which occur approximately 70% of the time, and facilitate approximately 40% of all departing aircraft when in operation. These percentages are based on an average of the last five years, and equates to approximately 60-70 flights per day for 70% of the year based on 2013 total aircraft movements. During 2013, 14,488 movements were recorded on the Runway 26 BPK departure route, 609 of which were at night. Night movements are defined as those that departed between 23:00 06:00, Mon-Sat and until 07:00 on Sunday. Table 1 details the 10 most frequent types of aircraft in operation along this route, and the percentage of traffic that is attributed to that aircraft. Anticipated passenger and traffic forecasts along the Runway 26 BPK departure routes up until 2030 are provided in Table 2, along with data from the last four years. Table 1. Aircraft type on Runway 26 Brookmans Park departures Aircraft Type Percentage A320 46% A319 15% B738 5% B734 3% C56X 2% GLF5 2% CL60 2% GLF4 2% GLEX 2% A306 2% Page 14 of 59
Table 2. Air traffic movements Totals and BPK departures Year Million passengers per annum Total Air Traffic Movements (ATMs) per annum 000s Runway 26 Departures per annum (in use for 70% of the time) 000s Runway 26 Departures on BPK route per annum (40% of R26 departures) 000s Average number of departures on BPK route per day when in use 2010 8.8 96 31 12 53 2011 9.5 99 36 15 57 2012 9.6 99 36 16 61 2013 9.7 98 31 15 62 2014 10.8 116 41 16 65 2015 11.2 118 41 17 66 2016 11.7 121 42 17 68 2017 12.1 124 43 17 70 2018 12.6 128 45 18 72 2019 12.9 130 46 18 73 2020 13.4 132 46 19 74 2021 14.3 137 48 19 77 2022 14.8 141 49 20 79 2023 15.4 144 50 20 81 2024 15.8 146 51 20 82 2025 16.6 150 53 21 84 2026 17.3 154 54 22 87 2027 17.7 156 55 22 88 2028 17.8 157 55 22 88 2029 17.8 157 55 22 88 2030 17.8 157 55 22 88 N.B. 2010-2013 are based on actual movement data, whereas 2014-2030 is a forecast based on upper end, unconstrained demand, assuming the development proceeds as planned (based on London Luton Airport Operations Limited Revised Masterplan document (http://www.london-luton.co.uk/en/about/). The adoption of RNAV1 along the Runway 26 BPK departure route will not have any impact on traffic forecasts, and does not affect the number or type of aircraft able to use the route or the Airport. It also does not affect the route flown once aircraft have passed St. Albans. Trial Results Following the trials, flight tracks were analysed to determine whether aircraft were able to fly the route more accurately than before. Figure 5 illustrates where aircraft using conventional procedures (non-trial) fly. Figure 6 and 7 illustrate where those using RNAV1 procedures flew during the 210 knots trial, while Figure 8 and 9 illustrate where those using RNAV1 procedures flew during the 220 knots trial. On the plot density diagrams yellow indicates the highest density of tracks, followed by red, pink then blue. Plot densities have been calculated using flight data from the duration of each trial, whereas sample flight tracks are provided from a week-long period during the trail. Track adherence was strong throughout both trials, and aircraft successfully navigated around areas of high population density. Aircraft were able to keep within the NPR rather than deviating south of it, which resulted in fewer aircraft flying over Hemel Hempstead and St. Albans. During the 210 knots trial, aircraft were initially being vectored before the railway line linking Harpenden to St. Albans. A slight adjustment was therefore made to the procedure for the 220 knots trial to ensure vectoring only occurred after this point. Other than this small change (which is visible on the plot densities below) there was little difference in track adherence during the 210 knots and the 220 knots trials. Page 15 of 59
Legend: ATMs Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 5. Existing Conventional Brookmans Park SID Plot Density Diagram Page 16 of 59
Legend: ATMs Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 6. RNAV 1 Trial SID with Initial Speed Restriction of 210 knots Plot Density Diagram Page 17 of 59
Legend: 210 knots flight tracks Current SID centreline Current NPR Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 7. RNAV 1 Trial SID with Initial Speed Restriction of 210 knots - Sample flight tracks Page 18 of 59
Legend: ATMs 1 2 7 8 3 4 5 6 Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 8. RNAV 1 Trial SID with Initial Speed Restriction of 220 knots Plot Density Diagram and Noise Monitoring Locations Page 19 of 59
Legend: 220 knots flight tracks Current SID centreline Current NPR Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 9. RNAV 1 Trial SID with Initial Speed Restriction of 220 knots - Sample flight tracks Page 20 of 59
9. Environmental Impacts The Airport has considered the environmental impacts of this proposed change in relation to the following five areas: Noise Population Overflown Fuel Burn and CO 2 Emissions Local Air Quality Tranquillity and Visual Intrusion Noise The noise of individual departures was monitored throughout the 210 knots and 220 knots trials at two fixed monitors located to the west of the Airport, and also for week long periods of time using a portable noise monitor at locations representing south Luton, Slip End, Flamstead, Hemel Hempstead, Redbourn and St. Albans. The locations of each monitoring point are displayed on the map in Figure 8. The monitoring sites were identified with the help of LLACC and Noise and Track Sub-Committee (NTSC) members who provided advice on suitable locations. Monitoring data was collected for a period of six months. Summer daytime L Aeq, 16 hours noise exposure contours and sound exposure level (SEL) footprints have been calculated using the Federal Aviation Administration s (FAA s) Integrated Noise Model (INM), version 7.0d, and are provided in Appendices D and E. Historic summer contours can be found in the Annual Monitoring Reports which are published on the London Luton Airport website at the following link: http://www.london-luton.co.uk/en/content/8/231/noise.html Noise monitoring results When considering the results it should be noted that there are a number of variables that affect them. These include the routes flown by the aircraft, the destinations they are serving, and also the weather conditions at the time of the flights. The latter have the potential to affect both the heights of the aircraft, due to the wind speed and direction, and also the transmission of noise to ground level, as the reduction of noise over large distances is affected by the temperature and humidity. Aside from the effect on the noise from departures on a particular route, the weather also fundamentally affects where aircraft fly by influencing the runway direction used. This was demonstrated during the initial 210 knots trial when a prevalence of easterly winds meant many departures departed initially towards Stevenage. This meant they did not use the trial route and so the 210 knots trial was repeated. In the graphs of results that follow, the first period of the 210 knots trial is labelled 210 kt Trial (A) and the repeat period 210 kt Trial (B). Maximum noise levels (L Amax,s ) for the aircraft movements, and the sound exposure level or total noise for the aircraft movements (SEL) have been calculated for each monitoring location. The results for these two parameters are generally consistent with the SEL results being higher than the L Amax results by around 10 to 12 db which is usual for departing aircraft some distance from the airport. Graphs have been provided in Appendix C illustrating the results for the three key aircraft types that operate most frequently from London Luton Airport (the Airbus A319, Airbus A320 and Boeing B738), where at least 5 measurements were obtained. Where results are not displayed, this is due to insufficient data being collected. On the graphs for the fixed Noise Monitoring Terminals (NMTs) the Page 21 of 59
results for the noisiest type that operates with any regularity, the Airbus A306, are also displayed. There was insufficient data for this aircraft type from the mobile monitor. For each aircraft under each phase of the trial the graphs show the average value as a diamond, and a bar related to the spread of the results, strictly the 95% confidence interval for the data (i.e. the uncertainty in the value of the average, given the sample size and data spread). The length of the bar is larger when the results for a particular aircraft are inconsistent or when there are relatively few measurements of it. Some of this inconsistency may be due to the effect of weather conditions as noted above and so small changes between periods cannot be taken as showing an effect of the different routes flown. An indication of the weather effect is given by the results in the graphs for the current route which was still used by some aircraft during the trial periods. Taking the Airbus A320, the aircraft type where the greatest number of results from flights on the trial routes was obtained, the results from the fixed NMTs at Grove Farm, Pepperstock (NMT2) and Pepsal End Farm (NMT3) demonstrate a negligible difference in noise levels between the trials and non-trial at these locations. As can be seen on the plot density diagrams in Figures 6 and 8, this is because there is no change to the route as the aircraft passes these locations. The results from these locations are based on the largest sample size because the monitors were fixed at these locations throughout the trials, and therefore the 95% confidence bars are shorter. Similarly, a negligible change was anticipated in south Luton, Slip End and Flamstead because it was thought there was little change to the flight tracks during the trials compared to non-trial past these locations. Noise levels in south Luton during the 220 knots trial could not be verified because no data was collected. Due to an extended period of easterlies limiting the number of days that noise data could be collected, and the fact that negligible change in south Luton was anticipated the mobile noise monitor was moved to other locations. Noise levels in south Luton during the 210 knots trial however rose unexpectedly compared to outside the trial period, and a small increase was also measured during the 220 knots trial in Slip End. These may be partly due to weather conditions during the trial period as aircraft flying both the current and the trial procedures were similarly affected. These increases have also been attributed to aircraft making a later first turn during the trial as an unintended consequence of the RNAV1 trial route design. In the event that an RNAV1 SID is adopted this will be addressed to ensure the first turn is initiated as per the current route design, at approximately 1,000ft depending on weather conditions (i.e. at 1030ft QNH), ensuring that noise levels remain unaltered in south Luton and Slip End. The proposed AIP chart in Appendix B has been revised to incorporate this change. In Flamstead, a slight decrease in noise levels was measured for all routes during the 210 knots trial period compared with before the trial, with those aircraft flying the RNAV1 procedures measuring slightly higher compared to those not on the trial. The number of aircraft using the Runway 26 BPK departure routes during this period was however low, which is evident from the large error bars, and suggests that this result is not conclusive. The noise levels measured during the 220 knots trial suggested negligible change. During the trial little data was collected from the monitoring site in Redbourn. With the majority of aircraft (trial and non-trial) passing to the south of Redbourn, at altitudes of approximately 4,000ft, departure noise levels registered by the mobile noise data were often similar to ambient noise levels in that location, close to the M1 motorway and could not therefore be clearly correlated to specific aircraft departures. Page 22 of 59
The longest measured change in noise level was a reduction in noise at Hemel Hempstead. The plot densities in Figures 5, 6 and 8 clearly illustrate the cause of this reduction, as the RNAV1 route directs aircraft away from the northern edge of the town. The sample size was again limited during the 220 knots trial due to an inability to clearly correlate the data due to the distance between the noise monitor and aircraft on the new route. The noise monitor at St. Albans was located north of the city, just west of Sandridge. The RNAV1 trial directed the majority of aircraft almost directly over this location, in comparison to the current situation where dispersal generally occurs before this point, resulting in a number of aircraft flying over residential areas in north St. Albans. The results suggest a slight increase in noise at the monitoring location which is expected due to the increase in aircraft flying over this less densely populated area. Comparing the aircraft types the 95% confidence bars are generally largest for the Airbus A306 and Boeing B738 where they are present. This reflects the limited number of results for these types. In the case of the Airbus A306 this is because it only forms a small proportion of the aircraft mix. For the B738, although it operates more frequently, most of its departures do not use the Runway 26 BPK departure route, instead using the other two routes from Runway 26 towards Compton and Olney. As noted earlier some of these changes may also be the result of the natural variation in measured noise levels that occurs, due to a range of factors such as the weather and not the change in routes. This effect is illustrated in Appendix C where the SEL results from south Luton are given. The average result for the Airbus A320 using the current Runway 26 BPK departure route before the trial is 87.4 db(a) SEL and after the trial is 88.6 db(a) SEL. Both of these averages are based on over 100 results but still differ by around 1 db(a). When the contour validation exercise is undertaken, the results from the fixed monitors are used and thousands of data points analysed. Noise Exposure Contours Noise exposure contours have been produced, which are a measure of noise energy averaged over 16 hours, and show lines joining points of equal noise energy, measured in decibels (db) around the Airport. The closer to the source of the noise energy i.e. the aircraft engines, the higher the energy and the higher the db value. At points further from the source, there is less noise energy and the db value is lower. These have been produced using the FAA s Integrated Noise Model (INM) Version 7.0d. The methodology has been validated by comparing the INM predicted individual aircraft noise levels with those recorded at the Airport s fixed noise monitors in 2012. The contours are produced from 57 db LAeq, at 3 db(a) intervals and also as a sensitivity analysis at 54 db LAeq. Summer daytime L Aeq, 16 hours noise exposure contours have been calculated for current procedures and the situation that would arise immediately in the event that an RNAV1 route with a 210 knots or 220 knots initial speed restriction is adopted (based on 2013 traffic data). This assessment assumes that all aircraft would be able to adopt the RNAV1 procedure, therefore presenting the most extreme change feasible, and the detailed methodology includes revised profiles for the departing aircraft to allow for the lower speed associated with the trial routes. Appendices D1 and D2, for the RNAV1 210 knots and 220 knots routes respectively, illustrate the contours for the 2013 summer period, for both the current situation and the situation immediately following the adoption of RNAV1 along the Runway 26 BPK departure route. The contours for 63 to 72 db LAeq,16h are identical in all scenarios, with a slight difference visible in the 54 to 60 db LAeq,16h contours to the north of Flamstead. Considering the 57 db LAeq,16h contours, these extend from near Page 23 of 59
St Paul s Walden east of the Airport to south of Slip End to the south-west of the Airport. In doing so, the contours contain parts of south Luton, Slip End and Breachwood Green. Appendices D3 and D4, for the RNAV1 210 knots and 220 knots routes respectively, illustrate the contours using forecast future traffic (throughput 18mppa), for both the current routes and the routes following the adoption of RNAV1 along the Runway 26 BPK departure route. Similarly to the 2013 situation, the contours for 63 to 72 db LAeq,16h are identical in all scenarios, with a slight difference visible in the 54 to 60 db LAeq,16h contours to the north and west of Flamstead. The eastern edges of these contours have been cut off to enable the scale to be as large as possible, however there would be no change to the boundary of the eastern extreme in the event that either RNAV1 SIDs were adopted compared to if there was no change. The 2028 contours have been produced using the same methodology as for the current situation. In practice, the contours must be considered approximate as it is the intention to upgrade all the departure routes at Luton to use RNAV1 technology, as well as the Runway 26 BPK routes. For these contours the aircraft mix differs from that flown in 2013 due to the assumed introduction of some re-engined narrow bodied single aisle transports, i.e. Airbus A319neo, A320neo/A321neo, and Boeing 737 MAX 8. Comparing the contours based on 2028 activity with the contours which use the 2013 activity identifies an increase in contour size. The 57 db LAeq,16h contours now extend past St Paul s Walden east of the Airport, and further to the south of Slip End to the south-west of the Airport. In doing so the contours contain larger parts of south Luton, Slip End and Breachwood Green. This is to be expected given the greater level of activity anticipated by 2028. Table 3 below shows the cumulative area, population, and number of households within the 2013 summer contours as well as the area, population, and number of households within each 3 db contour interval. The No Change contours are based on current procedures; whereas the With Change contours are based on current procedures for Compton and Olney, and RNAV1 procedures for Clacton, Dover and Detling. Table 4 shows the same information for the 2028 summer contours. The 2028 contours differ from those presented with the recent planning application as the contouring methodology has subsequently been updated to include the latest version of the modelling software which was not available when the application was made. In both tables the results for the RNAV1 210 knots and 220 knots trial routes are identical and so the results have only been presented once. Reviewing the information in Table 3 finds there is no difference between the current situation based on 2013 summer movements and the situation that would have arisen in the same period if one of the trialled RNAV1 routes had been used. Comparing the future scenarios, shown in Table 4, the scenario where trialled RNAV1 routes are used is slightly better in terms of households, however the difference is small and there is no difference in the population. The tables also show that with the forecast activity in 2028 the contours are larger and contain a greater population and number of households, when compared with the 2013 contours. Page 24 of 59
Table 3. 2013 Summer Noise Contour Data L Aeq,16h Contour Level, Area (km 2 ) Population (in hundreds) Households (in hundreds) db No Change With Change No Change With Change No Change With Change >54 24.2 24.2 130 130 55 55 >57 13.8 13.8 71 71 30 30 >60 8.4 8.4 32 32 12 12 >63 4.8 4.8 11 11 4 4 >66 2.3 2.3 0 0 0 0 >69 1.3 1.3 0 0 0 0 >72 0.8 0.8 0 0 0 0 54-57 11.4 11.4 59 59 25 25 57-60 5.4 5.4 39 39 18 18 60-63 3.6 3.6 21 21 8 8 63-66 2.5 2.5 11 11 4 4 66-69 1.0 1.0 0 0 0 0 69-72 0.5 0.5 0 0 0 0 No change contours based on current procedures; With change contours based on RNAV1 procedures for Runway 26 BPK departures. Table 4. 2028 Summer Noise Contour Data L Aeq,16h Contour Level, Area (km 2 ) Population (in hundreds) Households (in hundreds) db No Change With Change No Change With Change No Change With Change >54 34.8 34.6 172 172 73 73 >57 19.6 19.5 111 111 48 47 >60 11.3 11.3 59 59 24 24 >63 6.8 6.8 24 24 9 9 >66 3.7 3.7 4 4 2 2 >69 1.8 1.8 0 0 0 0 >72 1.0 1.0 0 0 0 0 54-57 15.2 15.1 61 61 25 26 57-60 8.3 8.2 52 52 24 23 60-63 4.5 4.5 35 35 15 15 63-66 2.9 2.9 20 20 7 7 66-69 1.9 1.9 4 4 2 2 69-72 0.8 0.8 0 0 0 0 No change contours based on current procedures; With change contours based on RNAV1 procedures for Runway 26 BPK departures. Sound Exposure Level (SEL) footprints SEL footprints show the extent of noise energy generated from a single aircraft taking off (in contrast to the summing of events in noise exposure). The 90 db(a) SEL corresponds to the threshold of sleep disturbance. SEL footprints at 80 db(a) and 90 db(a) have been computed using the FAA s Integrated Noise Model (INM), version 7.0d, and have been prepared for the most frequent type (currently the Airbus 320) and the noisiest type (currently the Airbus A306). These two types are forecast to still constitute the noisiest and most frequent in 2028. Some of the Airbus A320 aircraft will however be replaced by the re-engined Airbus A320 neo aircraft which will be quieter. SEL footprints have been computed for each aircraft operating on the centre track of: a) The existing published SID/NPR b) The current actual track c) The 210 knots RNAV1 trialled route d) The 220 knots RNAV1 trialled route Page 25 of 59
Appendix E1 illustrates the extent of the 80 and 90 db(a) SEL footprints for an Airbus A320 departing to a destination between 500 and 1,000 nautical miles away (INM stage length 2) on Runway 26 using the current and trialled BPK procedures. These include assuming the aircraft flying along the nominal track of the published BPK route. This is to some extent of limited interest because aircraft are not currently able to fly this route accurately, as detailed in Figures 1 and 2. Also included are the same footprints based on the mean track actually flown in recent years. Appendix E2 shows similar information for the Airbus A306 aircraft, again at INM stage length 2. Comparing the SEL footprints from the trialled RNAV1 210 knots and 220 knots routes to the current route there is no difference in the 90 db(a) SEL footprints and the only difference in the 80 db(a) SEL footprints is a small reduction in extent over the lightly populated area to the south-west of Flamstead with the adoption of RNAV1. This is because the lower speed results in slightly lower noise levels, and this effect is slightly more visible for the Airbus A320 than the Airbus A306 as it reaches these speeds earlier. The results from the Airbus A306 again suggest there is no difference in the 90 db(a) SEL footprints for the different routes. Given their larger size, the difference in the area covered by the 80 db(a) SEL footprints is more significant but remains mainly over the lightly populated area to the south and south-west of Flamstead. Appendix E also illustrates that there is negligible difference in 80 db(a) and 90 db(a) SEL footprints between the trialled RNAV1 210 knots and 220 knots routes. This is true for both the Airbus A320 and the Airbus 306. Population Overflown The Government s overall policy on aviation noise as established in the Aviation Policy Framework is to limit and, where possible, reduce the number of people in the UK significantly affected by aircraft noise. A population assessment was undertaken following the RNAV1 210 knots and 220 knots trials to determine whether adoption of RNAV1 along this route would support this policy. As illustrated in Figures 1 and 2 aircraft under current procedures do not fly within the NPR, and so using this area as the basis of the population assessment would not accurately reflect the benefits associated with RNAV1. Two alternative methodologies have therefore been used for this assessment, and for each the population count is split by aircraft altitude. The first methodology takes the swathe overflown to be an area centred on the average track flown in both the trials and from non-trial flights, from the end of the runway to the location where the current and trial routes meet in the vicinity of the railway line from Harpenden to St. Albans. This endpoint was chosen because it is the point at which traffic may be vectored from the SID by ATC. The width of the swathe was taken as 3km for the existing route (as per the current NPR swathe) and 2km for the 210 knots and 220 knots RNAV1 routes (due to the proposal to restrict the NPR to this width). As a sensitivity study, the population overflown by a 3km swathe around the 210 knots and 220 knots routes was also assessed. Results of this population assessment are included in Table 5. The assessment details cumulative population data up to 6,000 ft to ensure the full impact of the proposal is presented, particularly over highly populated areas such as Hemel Hempstead and St. Albans. It also illustrates whether the trial routes have an effect on how quickly the aircraft reach higher altitudes. Page 26 of 59
Table 5. Population assessment using a swathe around the average flight track. Altitude Population Assessment (Cumulative) Current Actual Overflown (3km swathe) RNAV1 210 knots route (2km swathe) RNAV1 210 knots route (3km swathe) RNAV1 220 knots route (2km swathe) RNAV1 220 knots route (3km swathe) <2,000 ft 2,700 2,700 2,700 2,800 2,800 <3,000 ft 6,200 5,600 6,100 5,700 6,200 <4,000 ft 10,300 6,900 10,400 7,100 10,500 <5,000 ft 21,500 8,200 16,700 7,500 15,700 <6,000 ft 25,600 8,400 17,800 7,500 15,700 Total 25,600 8,600 21,500 7,700 19,500 The second methodology was to base the swathe boundaries on the observed radar track density plots available from the Airport s noise and track keeping system. This is again from the end of the runway to the location where the current and trial routes meet in the vicinity of the railway line from Harpenden to St. Albans. Table 6 again provides the cumulative results up to 6,000 ft. Figures 10, 11 and 12 show the areas that have been used for each non-trial, RNAV1 210 knots and 220 knots trial population assessments. Table 6. Population assessment using the plot density maps Altitude Population Assessment (Cumulative) Current Actual Overflown RNAV1 210 knots route RNAV1 220 knots route <2,000 ft <50 <50 <50 <3,000 ft 600 1,900 1,900 <4,000 ft 800 2,300 2,200 <5,000 ft 9,300 2,400 2,300 <6,000 ft 11,400 2,400 2,300 Total 11,400 2,600 2,400 As can be seen clearly from the results of both methodologies, the total population overflown will be greatly reduced in the event that either RNAV1 route is adopted. There was a slight reduction in total population overflown during the 220 knots trial compared to the 210 knots, however this difference could be explained by the introduction of the vectoring restriction before the railway part-way through the trials. Even when assuming a 3km swathe will be maintained with the introduction of RNAV1, the results in Table 5 still show a significant improvement over the current route once the second turn had been completed. For areas before the second turn the results show that the expected reduction in population is largely due to the anticipated reduction in swathe width. At lower altitudes, Table 6 suggests that the population overflown during the trials was greater than during current operations, however this result is not found with the other methodology reported in Table 5. As detailed in Section 9 (Noise Monitoring Results) aircraft made a later first turn during the trial as an unintended consequence of the RNAV1 route design, resulting in aircraft tracking further over South Luton. In the event that an RNAV1 route design is adopted this will be addressed to ensure the first turn is initiated as per the current route design (i.e. at 1030ft QNH), ensuring that noise levels and the population overflown at lower altitudes remain unaltered in south Luton. This will ensure that with the adoption of an RNAV1 route design, the total population overflown is reduced by tracking aircraft away from Hemel Hempstead and St. Albans without increasing the population overflown at lower altitudes. The AIP in Appendix B has been revised to incorporate this change. Page 27 of 59
Legend: Radar swathe boundary 3km swathe boundary based on average flight tracks Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 10. Population assessment areas flights not on the trial. Legend: Radar swathe boundary 2km swathe boundary based on average flight tracks Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 11. Population assessment areas Based on RNAV1 trial flights with an initial speed restriction of 210 knots Page 28 of 59
Legend: Radar swathe boundary 2km swathe boundary based on average flight tracks Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 12. Population assessment areas Based on RNAV1 trial flights with an initial speed restriction of 220 knots Fuel Burn and CO 2 Emissions Track data from both trials has been used to determine the impact on fuel burn and associate CO 2 emissions. This assessment was undertaken using KERMIT, NATS bespoke fuel burn model, and provides an estimate based on the aircraft s height, speed, type and phase of flight (cruise/climb/descent) up until the point at which the route crosses the railway line from Harpenden to St. Albans. This endpoint was chosen because if an RNAV1 procedure is adopted it will generally be ensured that aircraft track within the swathe until crossing this point (subject to ATC vectoring earlier due to safety or operational reasons). KERMIT refers to the BADA (Base of Aircraft Data) database (version 3.10) to determine aircraft performance (e.g. mean fuel flow) for an aircraft type at a particular flight level, phase and speed. KERMIT estimations of fuel burn and CO 2 emissions are very much dependent on the various assumptions used for the constants and formulae in the design, as well as the accuracy of inputs to the model. Ultimately, the study of aircraft fuel burn and CO 2 emissions is a complex science and, as such, the model itself requires these assumptions. Table 7 summarises the results. Page 29 of 59
Table 7. Fuel Burn Analysis Average fuel burn per flight (kg) Average CO 2 per flight (kg) Average track extension per flight (NM) Sample size Current route 312 990 4.41 1,823 RNAV1 210 298 948 4.12 820 knots RNAV1 220 knots 292 929 3.92 845 NB. Track extension is calculated by comparing the distance flown and the great-circle distance from first to last radar point for each flight. The results demonstrate that both RNAV1 routes reduce the amount of fuel burnt and CO 2 emitted compared to the current route due to a small reduction in track miles and savings are greatest on the RNAV1 220 knots route. Based on total aircraft movements in 2013 (Table 2), if the RNAV1 220 knots route is adopted, 290 tonnes of fuel and 885 tonnes of CO 2 would be saved annually. This equates to over 250,000 saved on fuel per year. Similarly, if the RNAV1 210 knots route is adopted, 203 tonnes of fuel and 609 tonnes of CO 2 would be saved annually. The rationale behind the proposed change is purely based upon environmental improvement, particularly with regards to a reduction in the number of people overflown. The economic benefit in terms of the fuel saved is of lower consequence, although not immaterial. Local Air Quality Local air quality is not anticipated to be affected by the adoption of RNAV1 along the Runway 26 Brookmans Park (BPK) departure routes. Air quality at the Airport will remain unchanged, and whilst fuel burn will be reduced if the proposal is adopted, the resultant benefits at ground level will be negligible. Tranquility and Visual Intrusion The Chilterns is a designated Area of Outstanding Natural Beauty (AONB) stretching from the Thames north of Reading some 70km to Hitchin. The area skirts the south-west of Luton, and both the current and proposed Runway 26 BPK departures fall slightly within the boundary for a short stretch between Markyate and Flamstead heading into the second turn. The adoption of neither RNAV1 options along this route is anticipated to alter the tranquillity of the Chilterns compared to the current situation. Maps illustrating the AONB in relation to the current and proposed NPRs are provided in Figures 13 and 14 below. Page 30 of 59
Legend: Current departure flight tracks Current NPR (3km swathe) AONB Current SID Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 13. AONB and current NPR corridor and example flight tracks Page 31 of 59
Legend: RNAV1 proposed NPR (2km swathe) AONB RNAV1 SID Crown Copyright. All rights reserved. London Luton Airport, O.S. Licence Number 0000650804 Figure 14. AONB and proposed RNAV1 NPR corridor Page 32 of 59