Business case for LPV implementation at Habib Bourguiba International Airport MEDUSA project

Transcription

1 Business case for LPV implementation at Habib Bourguiba International Airport MEDUSA project Page 1 of 34

2 Executive Summary This document presents a business case for the introduction of an APV SBAS (LPV) approach procedure in Monastir, Tunisia (hereinafter referred to as Monastir Airport). The runway at Monastir has ILS installed at Runway (RWY) 07, and various non-precision approach procedures at each end of RWY 07/25. The analysis provides an assessment of the impact of new APV SBAS (LPV) procedure to reduce the number of disrupted movements at the airfield by examining the impact of meteorological conditions on approach operations; and avoid potential future costs for installation of ILS on RWY 25. APV SBAS (LPV) procedures allow operations in lower visibility than non-precision approaches such as those based on NDB or VOR/DME. So, in some meteorological conditions, using APV SBAS (LPV) approach procedures would allow continued operations at Monastir for example in situations where ILS is not available due to scheduled maintenance or failures. The study, for reduction in disrupted movements: 1. Examined planned aircraft movements for the year 2012; 2. Examined historical meteorological data for the years ; 3. Correlated each planned aircraft movement against the corresponding statistical meteorological conditions at the time; and 1. Determined whether the available minima at the aerodrome meet the prevailing limits for visibility, cloud base and tail wind for each movement. To examine the level of benefit the following scenarios were defined: 1. Baseline: Considered the current implementations as available today; 2. Scenario 1: Considered the introduction of an APV SBAS (LPV) approach to the ILS runway end (RWY 07); 3. Scenario 2: Consideredd the introduction of an APV SBAS (LPV) approach to the RWY 07 and also the non-ils runway end (RWY 25). Using a discount rate of 8% as recommended by Eurocontrol for investments in ATM, the Net Present Value (NPV) of the LPV procedure implementation at Monastir in 2018 is as follows: Scenario 1: Scenario 2: - 31k 3,648k This confirms that from the financial point of view Scenario 2 is the only beneficial Scenario. Nevertheless, it has to be noted that there are safety benefits from introducing APV SBAS approaches on both RWY ends due to vertical guidance being provided to aircraft even when ILS is not available. Page 2 of 34

3 Contents 1.1 General Background Objectives and scope Document structure General Geographical location Traffic statistics Supporting navigation infrastructure Runway capabilities Meteorological conditions and limitations Visibility and cloud ceiling Wind analysis General Scenario definition Analysis methodology reduced disruption Step 1) Total aircraft landings Step 2) Non-ILS aircraft landings Step 3) Disruption probability per approach type Step 4) Aircraft disruptions Step 5) Total cost savings Improvement in serviceability (reduced disruption) Fuel savings from reduction of track miles ILS savings Procedure design and implementation Navigation infrastructure costs CBA results List of figures Figure 4-1: Location of Monastir airport Figure 4-2: Arrivals by hour and flight rules Figure 4-3: Distribution of arrival traffic for aircraft types with >15 landings Figure 4-4: RWY 07 prevailing wind conditions Page 3 of 34

4 Figure 4-5: RWY 25 prevailing wind conditions Figure 5-1: Estimated approach minima for RWY Figure 5-2: Analysis methodology Figure 5-3: NPA landing conditions Figure 5-4: Hours where specified IAP would not have been available by approach category RWY Figure 5-5: Likelihood of disruption logic Figure 6-1: Vertical profile of CFIT accidents / incidents List of tables Table 2-1: Document references... 7 Table 3-1: Abbreviations and acronyms... 9 Table 4-1: Basic geographical information Table 4-2: Arrival statistics at Monastir Table 4-3: Arrivals by type of traffic Table 4-4: Supporting navigation infrastructure at Monastir Table 4-5: Runway characteristics at Monastir Table 4-6: Monastir IAPs and associated minima MDH (ft) Table 4-7: Runway lighting systems Table 4-8: Monastir proposed LPV approach minima MDH (ft) Table 4-9: Runway usage Table 4-10: RWY movements per hour Table 4-11: RWY use per hour Table 5-1: Parameters for determining cost of disruption Table 5-2: Estimated average annual avoided disruptions by scenario Table 5-3: Estimated annual savings in 2014 per scenario compared to the baseline Table 5-6: Indicative costs for the implementation of an ILS compared to an APV SBAS procedure Table 5-7: The list of additional cost items Page 4 of 34

5 1 Introduction 1.1 General This document is a deliverable prepared under project MEDiterranean follow-up for EGNOS Adoption (MEDUSA). The report is prepared by Helios and presents a business case analysis of the implementation of LPV procedures at Monastir airport in Tunisia. 1.2 Background This project has been commissioned by the European Commission. The aim of the project is the acceleration of the implementation of LPV approach procedures in the Mediterranean Region. Approach with Vertical guidance provided by Space Based Augmentation System (APV SBAS) procedures can enable low visibility operations when ILS is not available and with lower minima than for non-precision conventional approaches. APV SBAS procedures are particularly beneficial for business and general aviation users. These procedures can also incorporate curved segments in the arrivals (based on Advanced RNP and RNP AR APCH navigation specifications) that may provide an appreciable benefit to all airspace users in addition to an obvious benefit of the low visibility operations. Alternatively, APV SBAS procedure can allow straight-in approaches from directions where ILS is not available. The benefits (over non-apv procedures) therefore include: reduction in the number of disrupted aircraft due to weather when ILS is not available; and potentially avoid future costs for installation of ILS on RWY Objectives and scope This project addresses new IAP, in particular APV SBAS. These are often referred to as Localiser Precision with Vertical Guidance (LPV) approach procedures as they allow flying to LPV minima. The objective of this document is to assess the business case for implementation of LPV procedures at Monastir Airport. It provides an indication of the possible benefits that could be accrued at the aerodrome. 1.4 Document structure This remainder of the document is structured as follows: Section 2 contains the document references; Section 3 presents a list of the acronyms used; Section 4 discusses the operations and current implementation at Monastir; Section 5 presents the analysis of the financial impact of APV SBAS (LPV) procedures at Monastir; Page 5 of 34

6 Section 6 presents conclusions that have been reached in this analysis. Page 6 of 34

7 2 References Table 2-1 below document. shows the associated documentation referenced in this # Title [1] Standard Inputs for EUROCONTROL Cost 12/02/20-43 Benefit Analyses [2] Monastir Airport AIP documentation DTMB AD [3] Design of a LPV approach to RWY 07 for Monastir - Habib Bourguiba [4] Proposal of Instrument Approach Chart for Monastir Habib Bourguiba GNSS (RNAV) RWY 07 [5] List of obstacles for Instrument Approach at Monastir Habib Bourguiba GNSS (RNAV) RWY 07 [6] COMMISSION REGULATION (EC) No 859/2008 of 20 August 2008 amending Council Regulation (EEC) No 3922/91 as regards common technical equirements and administrative procedures applicable to commercial transportation by aeroplane [7] FilGAPP Business Case Reference MEDUSA_LPV_RWY_07 final.pdf ANNEX 1 CHART.pdf ANNEX 2 OBSTACLES.pdf EU OPS WP6 D1.0 Issue No 859/2008 Date V5.0 Dec 2011 n/a Jun 2013 Proposal v1.0 Proposal v1.0 Proposal v May May May August April 2013 Table 2-1: Document references Page 7 of 34

8 3 Abbreviations and acronyms Table 3-1 shows a list of abbreviations and acronyms used in this document. Abbreviation/acronym AIP APCH APV ASDA BRG CAA CAT CBA CLG CTR DA DH DME EGNOS ft GA GP HR IAC IAP ICAO ID IFR INOP LDA LNAV L LOC LPV MAG Definition Aeronautical Information Publication Approach Approach Procedure with Vertical Guidance Accelerate-Stop Distance Available Bearing Civil Aviation Authority Category Cost Benefit Analysis Cloud Ceiling Control zone Decision Altitude Decision Height Distance Measuring Equipment European Geostationary Navigation Overlay Service feet General Aviation Glide Path Hour Instrument Approach Chart Instrument Approach Procedure International Civil Aviation Organisation Identification number Instrument Flight Rules Inoperable Landing Distance Lateral Navigation Locator Localiser Localizer Performance with vertical guidance Magnetic Page 8 of 34

9 MDA MDH MEDUSA MET METAR NDB NM NOAA NPA OACA OCH PCN RNAV RVR RWY SBAS STAR SWY TDZ THR TODA TORA VFR VIS VNAV VOR WGS-84 Minimum Decision Altitude Minimum Decision Height MEDiterranean follow-up for EGNOS Adoption Meteorological Routine meteorological report Non-Directional radio Beacon Nautical Mile National Oceanic and Atmospheric Administration Non-Precision Approach Office de l Aviation Civile et des Aeroports Obstacle Clearance Height Pavement Classification Number Area Navigation Runway Visual Range Runway Satellite Based Augmentation System Standard Arrival Route Stopway Touch Down Zone Threshold Take-Off Distance Available Take-Off Run Available Visual Flight Rules Visibility Vertical Navigation Very High Frequency Omni-directional radio Range World Geodetic Survey Table 3-1: Abbreviations and acronyms Page 9 of 34

10 4 Current operations 4.1 General This section describes the operations and capabilities at Monastir airport. This is the baseline supporting infrastructure within which any new APV SBAS (LPV) procedure will be operated. 4.2 Geographical location Monastir (Al Munastir) is the eight largest city of Tunisia and a capital of the Monastir Region (or so-called Governorate). The population of the city is about 500,000 citizens. Monastir is a major tourist destination and is also located close to other popular tourist destinations such as Sousse, or Port El Kantaoui. The Monastir airport is located at the coast of Mediterranean sea in a relatively flat region, with the closest mountain range, The Dorsal, located approximately 70 km to the West. The Dorsal is the eastern extension of the Atlas Mountains and runs across Tunisia in a north-easterly direction. The basic geographical information from AIP is as follows. Country ICAO ID Direction and distance from Monastir Time zone Airport latitude Airport longitude Elevation / reference temperature 9.0 feet (3 meters) / 33 C Magnetic variation Types of traffic permitted Aerodrome class ATS operational hours Tunisia DTMB 4.1 NM North-West GMT ' " N ' " E 001 E (2005) IFR/VFR 4E 24H Table 4-1: Basic geographical informationn Page 10 of 34

11 Figure 4-1: Location of Monastir airport 4.3 Traffic statistics Monastir is the third largest airport in Tunisia in terms of number of passengers. In 2012, the airport had approximately 12,000 movements, ncluding passenger flights, cargo and business and general aviation movements, with approx. 1.2 million passengers 1. It has experienced a large drop in traffic in the last five years as the number of aircraft movements in 2007 was above 35,000 and the number of passengers was four times higher than today with over 4 million per year. Despite this fact, in 2011, Monastir still belonged to Top 25 African airports. 1 Source: Flight Global Pro database. Page 11 of 34

12 As the traffic data received covered only period from October 2012 until and March 2013 the following assumptions were used to extrapolate the traffic statistics to the whole year: the total number of aircraft movements in 2012 was 12,000; and the share of summer season traffic in total traffic is typically 79% 2. Since the introduction of APV SBAS (LPV) affects arriving traffic only, the arrivals have been further broken down into VFR and IFR in Table 4-2 below. Flight rules Number of arrivals IFR 5,575 VFR 322 IFR then VFR 103 Total 6,000 Table 4-2: Arrival statistics at Monastir These statistics show that the 93% of flights were IFR, compared to 7% VFR. The hourly statistics by flight rules are shown in Figure 4-2 below. It shows that IFR flights have peak between 11:00 and 15:00 local time. A relatively large number of IFR flights also arrive early in the morning. Vast majority VFR flights arrive between 07:00 and 15:00 with peak around noon. 700 Annual arrival movements VFR IFR Hour block Figure 4-2: Arrivals by hour and flight rules 2 Source: determined from total number of movements in 2012 and traffic statisticss provided by OACA. Page 12 of 34

13 Figure 4-3 below shows the distribution of arrivals by aircraft type. Only types with more than 20 landings per year are shown. The chart is colour coded by type of flight. A majority of arrivals at Monastir are operated by airlines using Boeing B737 (mostly 600 and 800 variants) and Airbus A320. More detailed statistics are provided in table below. Type of traffic Arrivals in 2012 Airlines 4,852 Regional 476 Business Aviation 98 General Aviation 472 Other 102 Total 6,000 Proportion 81% 8% 2% 8% 2% 100% Table 4-3: Arrivals by type of traffic Annual arrival movements Airlines Regional Business aviation General aviation Other Aircraft type Figure 4-3: Distribution of arrival traffic for aircraft types with >15 landings 4.4 Supporting navigation infrastructure The navigation infrastructure available within the aerodrome CTR is summarised in Table 4-4 below, all the information was derived from the AIP. Page 13 of 34

14 Navigation aid VOR/DME L LOC 07 ILS CAT 2 (1 E / 2005) GP 07 DME (collocated with ILS GP 07) ID Frequency Hours of operation Position of transmitting antenna coordinates (WGS-84) MON MHz H ' 17.80" N ' 53.50" E MS 275 khz H ' 31.6" N MIS MHz H MHz H 24 MIS CH 36X H ' 23.7" E 35 45'43.8" N '19.3" E 35 45'21.5" N '29.1" E 35 45'21.5" N '29.1" E Table 4-4: Supporting navigation infrastructure at Monastir The airport seems to be relatively well equipped with conventional infrastructure such as VOR/DME providing back-up to ILS on RWY 07 and enabling nonflights 24 hours per precision approaches on RWY Runway capabilities The runway at Monastir is an instrument runway available for day in accordance with the airport operating hours. The runway is suitable for all types of aircraft, including wide-body long-haul aircraft, and has the characteristics shown in Table 4-5. Page 14 of 34

15 Runway Characteristic True BRG Dimensions (m) Strength (PCN) and surface of RWY and SWY THR coordinates (WGS-84) THR elevation / highest elevation of TDZ of precision APCH RWY TORA (m) TODA (m) ASDA (m) LDA (m) x x 45 PCN 53/F/A/W/T Asphalt PCN 53/F/A/W/T Asphalt 35 45' 14.63" N 35 45' 41.81" N ' 17.75" E ' 11.13" E 8 ft / 8 ft 8 ft Table 4-5: Runway characteristics at Monastir An ILS precision approach is available only for the RWY providing VOR-DME approaches. All the approach types available at Monastir are listed in Table 4-6 below. 07, with RWY 25 that are currently Monastir present day approach capabilities Approach Type ILS CAT I straight in approach LOC (GP INOP) ILS CAT I circling VOR Y - straight in approach VOR Y - circling GPS straight in approach GPS circling L straight in approach L - circling VOR Z straight in approach VOR Z - circling RWY CAT A CAT B CAT C CAT D Page 15 of 34

16 RNAV VOR/DME straight in approach RNAV VOR/DME - circling VOR Y straight in approach VOR Y - circling GPS straight in approach GPS circling VOR Z straight in approach VOR Z - circling RNAV VOR/DME straight in approach RNAV VOR/DME - circling Table 4-6: Monastir IAPs and associated minima MDH (ft) The following table presents lighting system for both runway ends. Runway Characteristic High Intensity Runway Lights Runway End Identifier Lights Precision Approach Path Indicator Optical landing system Table 4-7: Runway lighting systems The preferred runway, given the availability of ILS, would normally (i.e. in favourable wind conditions) be RWY 07. However the traffic data analysis shows that there is slightly more arrivals on RWY 25 than on RWY 07 (see Table 4-9). We assume this is caused by prevailing wind conditions. This suggests that enabling an LPV approach on RWY 07 is as important as on RWY 25. Table 4-8 below shows the proposed LPV minima for RWY 07 and RWY 25. The analysis has assumed that an LPV would be available at both RWY 07 and RWY 25, with the same minima since no additional infrastructure is equired. Page 16 of 34

17 Monastir 07/25 proposed approach capabilities (based on 3% climb capable A/C) Approach Type LPV RWY 07 straight in LPV RWY 25 straight in Table 4-8: Monastir proposed LPV approach minima MDH (ft) The table provides LPV approach minima as displayed on proposed instrument approach charts. 4.6 Meteorological conditions and limitations This section examines meteorological conditions and resulting operational limitations at Monastir, as well as related runway utilisation Visibility and cloud ceiling Between 2008 and 2012, there were only 96 observations (0.2%) where the visibility was less or equal than the published RVR of 1200m for RNAV VOR/DME approach on RWY 07 3 (for category C aircraft). There were 10 observations (0.02%) where the cloud base was lower than RWY 07 s decision height of 510 ft for RNAV VOR/DME approach. As far as RWY 25 is concerned, there were only 123 observations (0.3%) where the visibility was less or equal than the published RVR of 2000m for RNAV VOR/DME approach on RWY 25. There were 10 observationss (0.02%) where the cloud base was lower than RWY 25 s decision height of 460 ft for RNAV VOR/DME approach Wind analysis CAT A CAT B CAT C CAT D This section presents analysis of wind conditions at Monastir to better understand the RWY usage and the operational limitations in terms of strong tailwind. The preferred runway, given the availability of ILS, would normally (i.e. in favourable wind conditions) be RWY 07. However the traffic data analysis shows that there is slightly more arrivals on RWY 25 than on RWY 07. The following table shows summary of runway usage during winter season between October 2012 and March About 52% of all the arrivals land on RWY 25 without ILS. This may be due to a large proportion of arrivals from Europe that may prefer straight-in approach to RWY 25 to save track miles, if the meteorological conditions permit Note that METAR observations were taken into account in one hour intervals. Page 17 of 34

18 Arrivals on RWY 07 Arrivals on RWY 25 Total arrivals Table 4-9: Runway usage Number of movements ,195 Proportion of movements 48% 52% 100% The following two figures provide more information on runway usage per hour in terms of number of movements and proportion of movements. RWY07 RWY Number of arrivals Hour Table 4-10: RWY movements per hour Page 18 of 34

19 RWY07 RWY25 Proportion of arrivals per RWY 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Hour Table 4-11: RWY use per hour The analysis of RWY use per hour shows that RWY 25 is more frequently used in the morning hours whereas RWY 07 is more often used in afternoon hours and in the evening. This was cross-checked with the analysis of wind conditions at both runway ends (see Figure 4-4 and Figure 4-5) using five years of meteorological data 4. The charts below present the average percentage per hour during which the tailwind strength exceeds a threshold value of 10 knots for each runway end. It is assumed that an aircraft will not execute an approach to a runway end if the tailwind strength exceeds this value. The analysis of wind conditions reveals that strong tailwind conditions prevent the use of RWY 07 less than 10% of the time. There is a significant proportion of time where RWY 07 can be used (above 90% of the time) even in the presence of a slight tailwind. Regarding RWY 25, strong tailwind conditions prevent the use of this RWY for a relatively significant amount of time in the afternoon hours (see Figure 4-5). For example, between 14:00 and 17:00 local time tailwind prevents landings on RWY 25 for more than 25% of the time. On the other hand, wind conditions in the morning hours are on average better than on RWY 07, with strong tailwind occurring less than 5% of the time and headwind or no wind occurring for approximately 60-70% of the time. 4 Database of Routine Meteorological Reports (METARs) at Monastir airport covering five years from 2008 to Page 19 of 34

20 Average % time in met condition 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 0 Strong tailwind Tailwind Headwind No wind Hour Figure 4-4: RWY 07 prevailing wind conditions Strong tailwind Tailwind Headwind No wind Average % time in met condition 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Hour Figure 4-5: RWY 25 prevailing wind conditions It could be concluded, that the wind conditions support the use of both RWYs, depending on the time of the day. This is also confirmed by the RWY usage analysis that showss both RWYs are used approximately the same amount of time. Given that majority of arrivals is coming from Europe straight in approach to RWY 25 may be preferred, if the meteorological conditions permit. We therefore infer that the implementation of APV SBAS approach at both runways ends is equally important. This was also taken into account in the financial analysis. Page 20 of 34

21 5 Financial Analysis 5.1 General This section describes an assessment of the operational capacity of Monastir based on the use of different available approach types. Each approach type allows an aircraft to execute an approach according to a specific Obstacle Clearance Height (OCH). The aircraft may be prevented from following the approach if at the time the meteorological conditions (i.e. visibility, cloud ceiling level, high tailwind component) exceed the limits of the procedure or the navigation aid supporting the procedure (e.g. ILS - either due to planned or unplanned service outage) is unavailable. In such circumstances the aircraft will most likely experience a disruption, defined as an aircraft delay, diversion or cancellation. The analysis assesses the varying number of hours of likely disruption experienced at Monastir depending on the available approach capabilities. 5.2 Scenario definition The following threee scenarios are defined for this financial assessment: Baseline scenario: This is the current day situation. The best available instrument approach procedure on RWY 07 is an ILS CAT I approach and on RWY 25 it is RNAV VOR/DME approach (or alternatively GPS non-precision approach with the same MDH as VOR/DME). Scenario 1: LPV implementation at RWY 07: This is an investigated alternative to the Baseline with the current trial LPV and LNAV/VNAV approach also implemented. This will provide an indication of any benefits or financial impact on the implementation of LPV as a back-up to the ILS implementation. Scenario 2: LPV implementation at RWY 25: This is an investigated alternative with the implementation of LPV and LNAV/VNAV approach capabilities for RWY 25 to enable near precision approach operations at both runway ends without the purchase, installation costs and on-going maintenance costs of an additional ILS. All benefits below for scenarios 1 and 2 are expressed as a comparative analysis against the baseline. The benefits of Scenario 1 are investigated in terms of the respective estimated number of avoided disruptions annually. The benefits of Scenario 2 are an aggregate of benefits from avoided disruptions annually and avoided costs relating to installation and operation of second ILS and approach lighting system. The estimated approach capabilities for both runways for Baro-VNAV approach (LNAV/VNAV minima) under Scenario1 and Scenario 2 are summarised in Table 5-2 (and compared to LPV). Presented LNAV/VNAV minima are assumed based on the obstacle environment surrounding the approach to both RWY ends. Page 21 of 34

22 Potential curved approaches onto RWY 07 and RWY 25, and associated reduction in track miles has not been examined as the procedure designed for Monastir Airport does not consider this option. Scenario 1 and Scenario 2: LNAV/VNAV implementation LNAV/VNAV estimated OCH (ft) Approach Type LPV RWY 07 LNAV/VNAV RWY 07 LPV RWY 25 LNAV/VNAV RWY 25 CAT A CAT B CAT C CAT D Figure 5-1: Estimated approach minima for RWY Analysis methodology reduced disruption The analysis employs a modular approach calculating in turn: the total number of aircraft landings at the airport; the number of non-ils landings from these; the disruption probability per approach type; the subsequent number of disrupted NPA landings; and the total cost of these disruptions. Page 22 of 34

23 1 ) Total aircraft landings 2 ) Non - ILS aircraft landings Dependent upon airport ILS capability and tailwind sets upper bound to potential benefits Dependent upon estimated DH (m), cloud ceiling & RWY visibility 3 ) Disruption probability per approach type Dependent upon landing aircraft capability and selected RNAV capability 4 ) Aircraft disruptions 5 ) Total cost savings Figure 5-2: Analysis methodology The individual analysis steps are described in more detail below Step 1) Total aircraft landings The total number of aircraft landings is derived from data provided by OACA. The analysis only considers Instrument Flight Rule (IFR) movements and not Visual Flight Rule (VFR) movements Step 2) Non-ILS aircraft landings The number of landings where an ILS approach is not possible (non-ils aircraft landings) is calculated based upon: an ILS annual outage probability of one week per year (either planned as part of maintenancee or unplanned); and a tailwind strength probability (when the tailwind strength exceeds the threshold, an approach must be made to the opposite runway end). Page 23 of 34

24 All weather data is derived from meteorological statistics provided by the National Oceanic and Atmospheric Administration (NOAA). These annual statistics include hourly, if not half hourly, observations of local meteorological conditions and are often the source for airport METARs. The station used is located at Monastir airport Step 3) Disruption probability per approach type The disruption probability per approach type is calculated based upon a combination of the approach OCH and meteorological conditions at the time of approach. It is assumed that, given a particular OCH or (Minimum) Decision Altitude/Height or (M)DA/DH, two dominant weather types will result in a disruption; poor runway visibility or low cloud ceiling. (M)DA/DH Required visibility Recorded visibility Recorded cloud ceiling Threshold (50ft) Runway Required cloud ceiling Figure 5-3: NPA landing conditions If the decision height of an approach meant that the (M)DA/DH was greater than the required cloud ceiling or the recorded visibility did not exceed the required level, then a disruption will ensue. The specific formulation of this follows. Applying a 3 glide slope, an aircraft descends at a rate of 300 feet/nm in the final approach. Hence, for a given DH: A) For the cloud ceiling, landings are not possible when: Recorded cloud ceiling (feet) < DH B) For visibility: Tan θ = descent rate = 300ft/NM (1 NM = km), where θ is the descent angle. DH/MDH (ft) = minimum decision height in feet Page 24 of 34

25 Minimum required RVR/visibility (m) = [(DH/MDH (ft) 0,3048) / Tan θ ] length of approach lights (m) Therefore, landings are not possible if: Recorded cloud ceiling < DH; OR recorded RVR/visibility (m) < [(DH/MDH(ft) x ) / Tan θ ] length of approach lights (m) This formula is evaluated for all hours providing a specific hourly probability factor to be applied at alll times. This is then applied to the estimated non-ils landings per year Step 4) Aircraft disruptions The number of aircraft disruptions is calculated by applying the estimated disruption probability factors to the estimated number of non-ils landings. As seen from the aircraft movements analysis, 81% of all aircraft landings are accounted for by the commercial air transport aircraft (B736, A320, etc.). These are mostly category C aircraft (according to ICAO aircraft landing speed categorisation) and can be expected to have high-end avionics on board. It is likely that all of these have or can be upgraded to LNAV/VNAV capability. The same is assumed about regional aircraft (usually category B) that epresent 8% of all landings. It is therefore assumed that all large transport and regional aircraft are LNAV/VNAV capable. Business and General Aviation aircraft represent 10% of all traffic and are a mix of category A to category C aircraft types. All these aircraft are expected to be already capable or upgradable to LPV capability. In addition, other types of aircraft operate at Monastir airport (military, helicopters, and utility aircraft). However as these represent only about 2% of all the traffic, they were excludedd from the cost benefit analysis Step 5) Total cost savings The subsequent cost of aircraft disruptions and potential cost savings between the various scenarios are calculated by applying an operator cost per disruption. The cost per disruption was determined by applying the following parameters: Page 25 of 34

26 Parameter Medium-sized aircraft Proportion of delay occurrences in total 90% disruptions Proportion of diversion occurrences in 10% total disruptions Time lost during delay 60 mins Time list during diversion 90 mins Cost per minute of delay 84 Average number of passengers on 150 board Value of passengers time 26.7 Total cost per disruption 5,871 Regional aircraft 90% 10% 60 mins 90 mins ,908 Table 5-1: Parameters for determining cost of disruption 5.4 Improvement in serviceability (reduced disruption) Most of the parameters presented in the table above either come directly from values recommended by Eurocontrol [1] or were calculated using parameters presented in [1].The total cost per disruption is assumed to be 5,871 for medium- sized aircraft and 3,908 for regional aircraft. This section presents the results of the analysis undertaken for reduced disruption as described above. The potential number of disruption hours per approach employing the above formula relating OCH, recorded cloud visibility. type is calculated ceiling and runway This is termed the potential number of disruption hours as actual disruptions only occur in the absence of ILS availability in the case of RWY 07. The actual number of disruptions depends upon the correlation of weather conditions and actual aircraft landing movements as well as the service availability of ILS and tailwind conditions at the time of landing. Nevertheless, this is a valuable exercise to perform as it provides an illustration of the potential effect of varying the OCH in accordance with the available runway approach capabilities. In general, the higher the OCH, the likelihood of a potential disruption is increased. However, this relationship between potential disruption and OCH is not linear. The critical value at which a reduction in OCH will enable dramatic reduction in potential disruption depends upon the average and variance of the cloud ceiling and runway visibility at the airport. Figure 5-4 below illustrates the number of hours when each IAP would not have been available due to MET conditions on an average year. The chart is colour coded to show potential disruption caused by the cloud cover being below the OCH (blue), and the visibility being lower than distance from the aircraft at OCH to Page 26 of 34

27 the runway (red). Each series distinguishes the data by ICAO aircraft category for each IAP VIS disruption CLG Disruption Figure 5-4: Hours where specified IAP would not have been available by approach category RWY 07 As expected, the ILS approaches suffer the least potential hours of disruption. It can be seen that the potential disruption to LPV is similar to ILS. There is only a slight increase when considering the potential disruption to the VOR-DME, this is due to the prevailing MET conditions. Overall the number of disruptions, as expected, is extremely low at Monastir due to favourable weather. For RWY 07 we would therefore expect little benefit from LPV in terms of reduced disruption. RWY 25 has only VOR-DME approach, which means thatt the probability of disruption is slightly greater than for RWY 07. As described in Section 5.2, Scenario 2 would employ LPV on RWY 25, based on the potential MET disruptions this would have a significant impact on reduced disruption. From the total number of potential disruptions per navigation aid, a comparison to the baseline scenario can be made. This comparison can be made with respect to: the number of disruptions saved by the introduction of LPV, and the financial benefit in reduced disruption costs as a result of the benefit. The level of disruptions needs to be based on the availability of the approach to arriving aircraft considering the meteorological conditions and the state of the navigation aids. The following figure illustrates the logic applied to determining whether for each of the scenarios a disruption occurred. The level of benefit afforded by LPV procedures within Scenarios 1 and 2 is then compared to the Baseline. Page 27 of 34

28 Figure 5-5: Likelihood of disruption logic Based on this analysis, the following table shows the estimated number of disruptions avoided compared to the baseline through provision of the LPV procedures at each runway end (note values are expressed as fractions due to the probability effect of ILS outages and weather phenomena). Total Scenario 1 Scenario 2 Less than Table 5-2: Estimated average annual avoided disruptions by scenario Scenario 1 (Monastir RWY 07 LPV deployment) The deployment of LPV at RWY 07 does not enable a noticeable reduction of disruptions per year. This small decrease is a result of the minima afforded by the available ILS and the small period of unavailability of the ILS that could be expected. It was assumed that all aircraft operated by airlines and regional operators are Baro-VNAV capable and can benefit from APV approach by flying to LNAV/VNAV minima. According to EU OPS, the minimum decision height for LNAV/VNAV approach is 300 ft. As the proposed IACs for Monastir do not include LNAV/VNAV minima, we assumed that the MDH would be 350ft. For the purpose of analysis, the proportion of BA and GA aircraft certified to fly LPV approach was assumed to be 100%, althoughh it is recognised that the current actual equipage rate may be lower. Page 28 of 34

29 Scenario 2 (Monastir RWY 25 LPV implementation) The implementationn of LPV at RWY 25, in addition to RWY 07, can be expected to similarly low benefits in terms of reduced disruptions per year. Converting these disruptions into financial benefits (based on the cost assumption in section ref), the corresponding annual estimated cost corresponding to these disruptions is presented below. Total Scenario 1 Scenario Table 5-3: Estimated annual savings in 2014 per scenario compared to the baseline This is best examined over the upcoming 5 years (short term forecast) to determine the potential cost savings and therefore trade-off in the implementation of LPV at RWY 25. This forecast assumes the disruption probabilities remain constant (and that therefore there is no significant change in the predominant wind conditions, cloud ceiling level and runway visibility). It assumes a 20% increase in the annual number of aircraft arrival movements based on the positive trend in movements in 2012 (+17.8% from 2011). This would mean that Monastir would get back to 2008 traffic levels again in The deployment and implementation of LPV at RWY 07 is calculated to only produce a cumulative cost saving of less than 3,400 in terms of reduced disruption over the next 5 years. This is expected since the minima provided by the ILS installationn on RWY 07 is similar to those available from LPV procedure within Scenario 1 and also thanks to excellent MET conditions. This is clearly not an adequate benefit alone to justify the cost of developing and implementing an LPV procedure at RWY 07. The deployment and implementation of LPV at RWY 07 and RWY 25 can be expected to enable a cumulative cost saving of 3,753 over the next 5 years compared to 33,600 costs for the implementation of LPV on RWY 25. Again, this is clearly not an adequate benefit alone to justify the cost of developing and implementing an LPV procedure at both runways Fuel savings from reduction of track miles Implementation of LPV approach at both runway ends may enable more flexible operations in certain weather conditions. In particular, introduction of SBAS approach with LPV minima at RWY25 may enable flights approaching airport from Eastern, North-Eastern and South-Eastern direction to approach straight in to RWY25 when cloud ceiling and visibility are below landing minima for GPS non- precision approach (or VOR/DME approach), but still above or equal to LPV landing minima. This could enable those flights to save track miles and reduce fuel burn, as they would not be required to circle round and land on RWY07. Page 29 of 34

30 The analysis of meteorological conditions and traffic, using probabilistic approach, proved that the potential savings would be minimal, even less than 100 per year. We have therefore not included this benefit into results ILS savings With the potentially avoided combined purchase, installation and on-going maintenance costss of ILS, the implementation of LPV procedure at RWY 25 in its place may pose a potentially beneficial alternative. It was assumed that a new ILS for RWY 25 would cost approx. 3m, including construction works, installation and lighting system, with further maintenance costs being 10% of these costs per annum. This would bring the total benefits of Scenario 2 to 4.3m by Procedure design and implementation Costs associated with the design and implementation of the new instrument approach procedures to Monastir were taken from FilGAPP project [7] or compiled from other sources. These indicative costs for the implementation of an ILS compared to an LPV procedure are summarised in the following table. Cost item Procedure design APV SBAS Approach 4,800 ILS Approach - Testing (Flight trials) 4,800 Chart preparation (AIP format) 3,300 AIP changes (publication) 300 TOTAL COST (EUR) 13, ,000 Table 5-4: Indicative costs for the implementation of an ILS compared to an APV SBAS procedure In addition to thesee costs, there are a number of other factors that may need to be included. Again, these are repeated from the FilGAPP project and are presented in the table below. Page 30 of 34

31 Activity Cost STAR design and publication (if needed) 2,400 Airspace design 6,000 Use of airspace rules establishment (optional) 1,800 Air traffic collision analysis with neighbouring aerodromes 1,200 Establishment of collision avoidance rules 4,800 Implementation of airspace changes 2,400 Co-ordination with other airspace users 1,200 Preparation of necessary documentation for CAA ratification of airspace 600 changes TOTAL COST (EUR) 20,400 Table 5-5: The list of additional cost items 5.6 Navigation infrastructure costs The provision of a LPV approach to either RWY 07 or RWY 25 does not require any additional investment on navigation infrastructure. 5.7 CBA results Using a discount rate of 8% as recommended by Eurocontrol for investments in ATM, the Net Present Value (NPV) of the LPV procedure implementation at Monastir in 2018 is as follows: Scenario 1: Scenario 2: - 31k 3,648k This confirms that from the financial point of view Scenario 2 is the only beneficial Scenario. Page 31 of 34

32 6 Safety improvements ICAO has recognised that the safety benefit provided by APV SBAS procedures is significant compared to non-precision approach procedures resulting from the vertical guidance which is provided to the aircraft on approach. Historically, the accident rates for aircraft following an NPA are because of an incorrect vertical profile, as illustrated by Figure o Outer marker, 5nm Altitude (meters) Distance to runway threshold (nm) Average time (seconds) Figure 6-1: Vertical profile of CFIT accidents / incidents At the 37 th ICAO General Assembly in 2010 a resolution was adopted that: all States to implement RNAV and RNP air traffic servicess (ATS) routes and approach procedures in accordance with the ICAO PBN concept laid down in the Performance-based Navigation (PBN) Manual (Doc 9613); Resolves that: a) States complete a PBN implementation plan as a matter of urgency to achieve: 1) implementation of RNAV and RNP operations (where required) for en route and terminal areas according to established timelines and intermediate milestones; and 2) implementation of approach procedures with vertical guidance (APV) (Baro-VNAV and/or augmented GNSS), including LNAV only minima, for all instrument runway ends, either as the primary approach or as a back-up for precision approaches by 2016 with intermediate milestones as follows: 30 per cent by 2010, 70 per cent by 2014; and b) ICAO develop a coordinated action plan to assist States in the implementation of PBN and to ensure development and/or maintenance of globally harmonized SARPs, Procedures for Air Navigation Services Page 32 of 34

33 (PANS) and guidance material including a global harmonized safety assessment methodology to keep pace with operational demands; and Urges that States include in their PBN implementation plan provisions for implementationn of approach procedures with vertical guidance (APV) to all runway ends serving aircraft with a maximum certificated take-off mass of 5,700 kg or more, according to established timelines and intermediate milestones. On this basis, even without the savings to flight disruption there is a requirement agreed to by ICAO State members for the adoption of APV procedures. In this case, the adoption of the APV SBAS (LPV) procedure for both RWY 07 and RWY 25 would be in accordance with this resolution which seeks to increase the safety of operations from aircraft having to use the traditional non-precision approach procedures. Page 33 of 34

34 7 Conclusions This paper has presented an initial impact assessment of the introduction of LPV procedures to Monastir airport. It has shown that, in addition to the safety benefits that have been recognised by the ICAO 37 th General Assembly, the introduction of LPV procedures to Monastir can have a benefit in avoiding potential additional ILS costs. Examination of the planned flight schedule for operations to Monastir for 2012 and 2013 has shown that the introduction of APV SBAS (LPV) approaches will not provide significant benefits in terms of reduced disruptions. This was examined through two scenarios to compare the benefits of a new procedure on a runway that has ILS and at both runways (Scenarios 1 and 2 respectively) against the currently available facilities. This assessment has shown that avoiding these disruptions does not deliver a direct financial benefit to the operators. However, the largest benefit in Scenario 2 comes from avoided costs of additional ILS on RWY 25 which amounts to approx. 4.3m by Using a discount rate of 8% as recommended by Eurocontrol for investments in ATM, the Net Present Value (NPV) of the LPV procedure implementation at Monastir in 2018 is as follows: Scenario 1: Scenario 2: - 31k 3,648k This confirms that from the financial point of view Scenario 2 is the only beneficial Scenario. Nevertheless, it has to be noted that there are safety benefits from introducing APV SBAS approaches on both RWY ends due to vertical guidance being provided to aircraft even when ILS is not available. This financial benefit assessment provides aircraft operators the basis from which to develop a complete business case that takes into account their aircraft equipage capabilities and the potential network benefits of utilising APV SBAS (LPV) procedures at other aerodromes. Likewise, the airport operator should take the findings of this report to undertake a more detailed analysis on the costs benefit case for the implementation of one or more procedures in line with the recommendations from ICAO for the replacement of NPA approaches. Indicative costs associated with the implementation of the procedures proposed in the scenarios within this report are provided. Page 34 of 34