Isdefe Status: Approved Page 1/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Document Description : This document aims to, on the one hand, state and discuss the strategic objectives, low level objectives and metrics of the OPTIMAL project, and on the other hand, review the level of success in meeting the targets. It summarizes the validation activities as performed and reported within WP7 and presents objectively and concisely the key findings of both the performance assessment exercises and the feasibility studies.
Programme: Sixth Framework Programme - Strengthening the competitiveness Contract Number: AIP3-CT-2004-502880 Project Number: FP6-2002-Aero-1-502880 Project Title: Optimised Procedures and Techniques for the Improvement of Approach and Landing Project Acronym: OPTIMAL Deliverable: D6.4 Document Title: OPTIMAL Validation Conclusions Document ID: WP6-ISD-096-V1.0-ED-PU Date: 14/11/08 Status: Approved Classification: PU File Name: OPTIMAL-WP6-ISD-096-Validation Conclusions-V1.0-ED-PU.doc
Isdefe Status: Approved Page 2/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Isdefe Status: Approved Page 3/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Isdefe Status: Approved Page 4/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Isdefe Status: Approved Page 5/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Isdefe Status: Approved Page 6/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Isdefe Status: Approved Page 7/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
ABAS Aircraft Based Augmentation System A/C Aircraft ACARE The Advisory Council for Aeronautics Research in Europe ACDA Advanced Continuous Descent Approach AFCS Automatic Flight Control System AMAN Arrival Manager ANSP Air Navigation Services Provider APM Approach Path Monitoring APW Area Proximity Warning APV (Precision) Approach with Vertical guidance AR Approval Required ATC Air Traffic Control ATCo Air Traffic Controller ATM Air Traffic Management CBA Cost Benefit Analysis CDA Continuous Descent Approach CNS Communication Navigation Surveillance CORADA Converging Runways and Approaches Display Aid dB Decibels DT Dual Threshold ECAC European Civil Aviation Conference E-OCVM European Operational Concept Validation Methodology ETMA Extended TMA EVS Enhanced Vision System FAA Federal Aviation Administration FLS FMS Landing System FMS Flight Management System FPAP Flight Path Alignment Point FT Feet FTS Fast Time Simulations GBAS Ground-Based Augmentation System GD Ground Development GLS GBAS Landing System GNSS Global Navigation Satellite System GPWS Ground Proximity Warning System HLO High-Level Objectives
Isdefe Status: Approved Page 8/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
IAF Initial Approach Fix ICAO International Civil Aviation Organization IFR Instrument Flight Rules INM Integrated Noise Model ILS Instrument Landing System LAAS Local Area Augmentation System (FAA) LLO Low-Level Objectives MLS Microwave Landing System MSAW Minimum Safe Altitude Warning MWM Multi Workload Model NAVAIDS Navigation Aids NM Nautical Miles OPTIMAL Optimised Procedures and Techniques for the improvement of Approach and
landing PA Precision Approach PINS Points in Space PITOT Integrated Work Platform for the Optimum use of analysis Techniques
(Plataforma Integrada de Trabajo para el uso Optimo de Técnicas de análisis) R/C Rotorcraft RNAV Radio Navigation, Random Navigation, Area Navigation RNP Required Navigation Performance RTS Real Time Simulations RWY Runway SBAS Space Based Augmentation System SDPS Surveillance Data Processing System SNI Simultaneous and Non-Interfering STCA Short Term Conflict Alert TAAM Total Airport and Airspace Modeller TMA Terminal Manoeuvring Area VMC Visual Meteorological Conditions WTC Wake Turbulence Category WTCA Wake Turbulence Conflict Advisory WTEA Wake Turbulence Encounter Advisory
Isdefe Status: Approved Page 9/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Isdefe Status: Approved Page 10/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Ref. 21 OPTIMAL “San Sebastian SBAS Cost-Benefit Analysis,” D7.1.4, WP7-ISD-086-V1.0-ED-CO, September 2008
Ref. 22 OPTIMAL “San Sebastian Airport SBAS APV Flight Test Report,” D7.4.2-2, WP7.4-AEN-021-V1.0-ED-CO, February 2008.
Ref. 23 OPTIMAL “Toulouse Airport A320 Autonomous FLS Flight Test Report,” D7.4.5-1, WP7-AIF-299-V1.0-ED-CO, October 2008
Ref. 24 OPTIMAL “Malaga real-time safety-oriented simulation for curved/segmented approach procedures,” D7.3.2-2, WP7.3-EEC-087-V1.0-ED-CO, July 2008
Ref. 25 OPTIMAL “RNAV Curved/Segmented Approach Procedures with Transition to ILS Flight Simulation Report,” D7.3.2-1, WP7-INE-129-V0.4-ED-CO, June 2008.
Ref. 26 OPTIMAL “A320 Low RNP Real Time Flight Simulation Report,” D7.3.1-1-RNP, WP7-AIF-278-V0.6-ED-CO, May 2008.
Ref. 27 OPTIMAL “Toulouse Airport A320 Low RNP Flight Test Report,” D7.4.4-1, WP7-AIF-279-V1.0-ED-CO, August 2008.
Isdefe Status: Approved Page 11/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
3.1 BACKGROUND ICAO forecasts a growth in world air travel of 5% per annum until 2005. Based on the experience in Europe, this appears likely to be a conservative estimate for this part of the world. Variations, regional as well in type of traffic, do occur; e.g. commuter traffic growing faster than long-haul. It is, therefore, not unreasonable to expect that air traffic in Europe may almost triple in the 2002/2020 timeframe, as stated in the Vision 2020 and the ACARE (The Advisory Council for Aeronautics Research in Europe) Strategic Research Agenda.
Consequently, airport congestion and environmental impacts become a mounting problem and are already a limiting factor at some airports. Many of the international hubs and major airport are operating at their maximum throughput for longer and longer periods of the day, and some have already reached their operating limits as prescribed by physical as well as political and environmental constraints.
Although there are sufficient airports and runways in Europe, the major airports are becoming, or continue to be, capacity constrained, resulting in significant delays, causing frustration and difficulties for both passengers and aircraft operator, and causing environmental problems. Even though aircraft have become less noisy over the past two decades the compounded effects of more movements over longer periods of the day and night have increased the disturbance. This has fuelled the resistance in the population living in the vicinity of an airport against further expansion of the facility and its operations.
In order to provide a response to the present airport capacity and future environmental constraints, additional procedures, operational concepts, technology and systems could be developed and implemented wherever required to better use available capacity and to provide additional capacity, and efficiency while minimizing the environmental impact of airport operations and maintaining or even improving safety.
At request of the Transport Ministers of the European Civil Aviation Conference (ECAC), EUROCONTROL developed the “Air Traffic Management (ATM) Strategy for the years 2000+” (Ref. 1). This ATM2000+ Strategy describes the processes and measures by which the forecast demand may be accommodated while improving aviation safety.
3.2 THE OPTIMAL PROJECT In order to provide some solutions to answer to the airport capacity and future environmental constraints, the OPTIMAL (Optimised Procedures and Techniques for the IMprovement of Approach and Landing, see Ref. 2) project was launched in 2004 in the 6th European framework and within the ATM2000+ Programme.
OPTIMAL is an air-ground co-operative project, aiming at defining and validating innovative procedures for the approach and landing phases of aircraft and rotorcraft in a pre-operational environment. The objective was to increase airport capacity while minimising noise nuisance and maintaining or even improving operational safety.
The work conducted during the 4½-year project ranges from the elaboration of the operational concept up to simulations and pre-operational flight trials implying effective modifications of avionics onboard aircraft and rotorcraft and ground systems. On the ground system side special attention was placed on the new tools, which were necessary for Air Traffic Controller to efficiently and safely manage the OPTIMAL procedures.
Isdefe Status: Approved Page 12/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
The target time frame for the operational implementation of the OPTIMAL proposed procedures is 2010 and beyond. OPTIMAL will therefore deliver an important contribution to the targets for airport capacity development identified in the ATM +2000 Strategy.
3.3 OPTIMAL ADVANCED PROCEDURES The achievements mentioned above were enabled by already available precision approach landing aids (ILS, MLS), as well as new satellite-based guidance systems (ABAS, SBAS, GBAS), more accurate navigation means (low RNP), enhanced airborne systems, and enhanced ground functions to support Air Traffic Control. More specifically, the following procedures were covered:
• For aircraft:
- Advanced Continuous Descent Approach (ACDA)
- Dual Threshold Approach (DT)
- Enhanced Vision System Approach (EVS)
- Straight-in approach with vertical guidance (LPV) based on ABAS
- Straight-in approach with vertical guidance (LPV) based on SBAS
- IFR Simultaneous and Non-Interfering (SNI) Approach
Table 1 summarizes the main expected benefits for each OPTIMAL advanced procedure.
New procedure Benefit
ACDA Reduction of noise and emissions with minimum loss of capacity.DT Increase of capacity by reducing wake vortex separation EVS Increase of situational awareness and to mitigate impact of low
visibility, thus enabling better accessibility particularly to non equipped airfields
LPV procedures based on SBAS or ABAS and GBAS precision approaches
Increase of safety in those runways not equipped with proper NAVAIDS systems. Also increase of capacity, and reduction of cost and environmental impact.
Straight-in curved / segmented RNP-AR
Avoid Noise sensitive areas providing track guidance to improved flight tracks. Provide safe and efficient instrument approach procedures in difficult environments due to terrain and obstacles. Improve safety and capacity in complex airports where simultaneous operations take place and in close-sited airports.
Steep Straight-in or Curved/ Segmented IFR SNI procedures for rotorcraft
Increase of passenger capacity by enabling R/C to reach busy airports by using specific / low noise IFR procedures that are independent from fixed wing aircraft traffic
Table 1 Expected benefits of OPTIMAL advanced procedures
Isdefe Status: Approved Page 13/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
3.4 VALIDATION DOCUMENTS AND PURPOSE OF CURRENT DOCUMENT An important integrated project such as OPTIMAL needs strong validation and safety plans in order to correctly assess the adequacy of the expected main results which address on the one hand the high level ATM objectives regarding capacity, safety, and environmental impacts and on the other hand the feasibility of the advanced procedures. To meet this aim, an overall validation plan has been elaborated, based on the “European Operational Concept Validation Methodology” (E-OCVM, Ref. 3), resulting in three main documents: D6.1 (Ref. 4) gives the validation strategy, including the validation requirements, metrics and hypotheses; D6.2 (Ref. 5) gives the validation exercise plans of all exercises. After conducting the exercises, the benefit assessment exercises were reported, and their results analysed, in D6.3 (Ref. 6). In order to place the current document in the right perspective, the validation strategy and exercise plan are summarized in chapter 4.
The main objective of the current document is, on the one hand, state and discuss the strategic objectives, low level objectives and metrics of the OPTIMAL project, and on the other hand, review the level of success in meeting the targets. It summarizes the validation activities as performed and reported within WP7 and presents objectively and concisely the key findings of both the performance assessment exercises and the feasibility studies.
3.5 STRUCTURE OF DOCUMENT This document begins, after the list of abbreviations and references (Chapter 1 and 2 respectively), with some background information about the OPTIMAL project and current document (Chapter 3), and a summary of the validation plan as drawn up before the exercises were carried out (Chapter 4). Then, chapters 5 to 11 describe the initial objectives, the validation exercises and the main results and conclusions of the validation exercises for the following procedures: ACDA, GNSS-based procedures, Curved RNP-AR Approaches, DT, EVS, IFR-SNI and ATC Safety Nets. Chapter 12 ends this documents with general conclusions about the success of the project in meeting its objectives and about consortium experience in applying a validation methodology.
Isdefe Status: Approved Page 14/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
4.1 VALIDATION OBJECTIVES The expectations summarized in Table 1, were the basis of the validation objectives of OPTIMAL. On a high level these objectives are simply given by “to demonstrate that OPTIMAL operational concepts contribute to increase capacity, reduce noise nuisance and improve safety”.
As assessing these objectives at such a high level is readily impossible, they were broken down into low level objectives, which are easier to be assessed during the validation process. The high level and low level objectives are given more detailed in the OPTIMAL Deliverable D6.1 (Ref. 4) and are also summarized in section 4.1 of D6.3 (Ref. 6).
4.2 VALIDATION TECHNIQUES As explained in OPTIMAL Technical Annex (Ref. 2), the most suitable validation techniques to be applied in the OPTIMAL validation process were Fast Time and Real Time Techniques.
Fast Time Techniques are suitable for a preliminary assessment of the benefits of a new concept in the ATM environment using a mathematical model to provide the results of the simulation and has rules defined to represent the relationship between the different actors of the validation scenario. In the OPTIMAL validation process Analytical Studies and Fast Time Simulation were applied as Fast Time Techniques:
• Analytical Studies are applied for safety, environmental and economic assessments:
- Safety cases: safety case for curved and segmented procedures; operational safety assessment of GBAS and SBAS flight trials; safety aspects of ACDA at Schiphol.
- Environmental assessments: CDA noise benefits on single event and airport scale for Airbus aircraft; noise footprint data for IFR R/C procedures; Malaga, San Sebastian and Schiphol noise analysis.
- Economics assessment: efficiency and cost-effectiveness study for San Sebastian LPV procedure.
• Fast Time Simulation (FTS) are applied for most of the capacity assessments.
- Airport capacity simulations for Malaga, San Sebastian and Schiphol.
Real Time Techniques are characterized by the presence of one or more subject matter expert as controllers or pilots that perform their operational tasks in a realistic real-time environment. Real time techniques are generally used for assessing the human factors aspects, but also to validate the interoperability between systems. In the OPTIMAL validation process, Real Time Simulation and Flight trials were applied as Real Time Techniques:
• Real Time Simulation (RTS) assess the acceptability and feasibility of the proposed procedures by human controllers (aircrew / ATCo´s):
Isdefe Status: Approved Page 15/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
- EVS Zurich simulation - Displaced Threshold Frankfurt simulation - Safety nets and monitoring aids simulations
• Flight trials assess the interoperability of on-board systems and navigation sensors and the fly ability of procedures and is the closest to real operations when the use of a new system or function is involved:
4.3 VALIDATION EXERCISES TYPES According to D6.1 (Ref. 4), there are two types of exercises to ensure the consistency of the overall validation process: benefit and feasibility assessments1. The following two sub-sections explain both types of assessments more detailed.
4.3.1 Benefit assessments Exercises of this type assess the benefits obtained from the implementation of the new procedure according to the high-level objectives capacity, environment and safety. All benefit assessment exercises were thoroughly described and analysed in D6.3 (Ref. 6) and will not be repeated here.
4.3.2 Feasibility assessments Feasibility assessments evaluate specific functions for airborne and ground system and include the validation of flyability requirements, operational requirements (both for pilot and controller), air-ground interoperability requirements and systems performance requirements.
Flyability exercises assess whether the procedure’s characteristics (as the path, the vertical profile, the radius turns, influence on runway operations) enable a successful operation of the aircraft/rotorcraft. They also test whether the aircraft/rotorcraft configuration is suitable to fly that procedure.
Operational exercises assess the pilot and controller tasks performed during the procedure, focusing on the interaction with the new or enhanced system, the acceptance of changes in respective roles derived from new procedures as well as the compatibility of their activities.
Air-ground interoperability exercises assess the compatibility between on the one hand on-board new systems and on the other hand ATC tools or navigation sensors. In the OPTIMAL project these assessments were focused on ATC tools enhanced within the project and on innovative sensors for the air navigation as GBAS or SBAS. 1 It is repeated here that unlike D6.3 (Ref. 6), where only benefit assessments were reported, the current document gives the overall conclusions for all OPTIMAL advanced procedures, resulting from both benefit and feasibility assessment results.
Isdefe Status: Approved Page 16/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
System performance exercises assess the performance of functions necessary for the implementation of a procedure. These functions were designed within OPTIMAL and are both for on-board systems and for ATC tools.
4.3.3 Data collection Benefit assessments were done with techniques that result in quantitative (measurable) data in order to express the change in the assessed indicator: Fast Time Techniques and in some occasions Real Time Simulations.
Feasibility assessments were based on both quantitative (recorded data) and qualitative data (subjective data, mostly provided by human actors, and obtained with techniques like debriefing sessions and questionnaires), but were always obtained through real time techniques (Real Time Simulations and Flight Trials).
Isdefe Status: Approved Page 17/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
5.1 PROCEDURE OVERVIEW Within the OPTIMAL project, the development of the advanced Continuous Descent Approach has multiple aspects, being on the one hand the (continued) development and assessment of a flyable descent procedure and on the other hand the integration of this procedure in the ATM environment. OPTIMAL focuses on two compatible variants of Continuous Descent Approach. The “nominal” CDA consists of a fixed earth referenced descent path of 2 degrees initially from the start of the CDA, changing to a 3 degrees path below an altitude of 3000ft. The CDA descent profile transitions into a conventional instrument final approach. Due to the fact that the procedure may be flown with a near-idle thrust setting, depending on the initial speed, the profile provides some control capability with respect to the deceleration profile to the ATC controller. The deceleration profile can either be flown with idle thrust, optimised by using the FMS for determining the configuration changes, while the profile can also be flown more conservatively for ATC sequencing reasons. Under such circumstances, imposed by other traffic, it may be necessary to initiate an earlier than optimum deceleration to a lower speed and perform a constant speed descent along the 2 deg gradient. The “optimised” CDA provides even more environmental protection as it is flown at relatively low speeds while maintaining the cleanest possible configuration and considering actual wind conditions. The vertical profile will be variable depending on actual wind conditions until transition to the fixed 2/3 degrees approach is made.
Isdefe Status: Approved Page 18/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
5.2 VALIDATION OBJECTIVES The following validation objectives were defined for the ACDA procedure:
1. Quantify the capacity benefits in terms of delay and separation for the new ACDA procedure compared to the traditional airspace organization procedures;
2. Determine a realistic traffic sample to accommodate an ACDA traffic flow from the last merge point to touch down (separation metric);
3. Assess the environmental benefit (noise nuisance) of ACDA approaches designed for the Schiphol airport (a) and a generic scenario (b);
4. Evaluate the ATC workload and the feasibility of the ACDA procedure with human in the loop;
5. Verify the maturity and performance level of the ACDA function and systems;
6. Assess the CDA function according to the operational context;
7. Assess general CDA usability and the impact of CDA tasks on current pilot's tasks;
8. Verify CDA vertical guidance performance and robustness;
9. Demonstrate the flyability and accuracy in 4D of a time referenced CDA with 4D guidance based on SBAS.
Table 2 summarizes the ACDA validation exercises performed in order to meet the above mentioned objectives.
5.3 EXERCISE SUMMARY Objectives 1 & 2 – Schiphol FTS Capacity simulations D7.2-3 “Schiphol Airport Capacity Simulation Results” (Ref. 7) summarizes the results of the capacity study performed in a fast-time simulation using TAAM (Total Airport and Airspace Modeller). It focuses on the ACDA procedures for the Schiphol situation. The exercises are summarized and analysed in D6.3 (Ref. 6).
Isdefe Status: Approved Page 19/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Objective 3 – Schiphol Environmental impact analysis D7.1.2-5 “Schiphol environmental impact assessment” (Ref. 8) gives the results of an environmental impact assessment with INM (noise) and LEAS-IT (emissions) on and in the vicinity of the aerodrome of Amsterdam Airport Schiphol using optimised & nominal CDA approaches. The exercises are summarized and analysed in D6.3 (Ref. 6).
Objective 3 – General Environmental impact analysis D7.1.2-1 “CDA Noise benefits on Single Event and Airport Scale for Airbus aircraft” (Ref. 9) gives the results of an environmental impact assessment with OCTOPER V24.0.0 on and in the vicinity of a generic 2-parallel runway airport using optimised and nominal CDA approaches. The exercises are summarized and analysed in D6.3 (Ref. 6).
Objective 4 – Schiphol RTS capacity and feasibility assessment D7.3.1-2 “NLR GRACE/NARSIM ACDA real-time flight simulation report” (Ref. 10) summarizes the results obtained from human-in-the-loop ATC and flight simulations of a number of operational concepts and enablers to implement advanced continuous descent approaches in a day-to-day operating environment for Schiphol airport. The simulator evaluations were performed using the NLR NARSIM ATC research simulator and NLR’s GRACE and APERO aircraft flight simulators. The capacity assessment was already elaborated in D6.3 (Ref. 6).
The following airport and airspace layout was applied during the simulator evaluations:
• A sufficiently large generic airspace without airport specific limitations and restrictions (>150NM out), although set in a Amsterdam Schiphol environment.
• Start of arrival management before top-of-descent. Within the scope of the present concept, the arrival management horizon was set to a distance of around 120NM from the airport.
• Predefined RNAV standard arrival routes and TMA transitions from cruise top-of-descent to the final approach. Sequencing activities should be accommodated by means of RNAV based path stretching, speed instructions, RTA instructions or a combination of these.
• The projected 2015 landing capacity assumed 30 arrivals/hr/runway on average with a peak arrival capacity of 33 landings/runway.
• Nominal CDA descent profile to the runway starting at 7000ft. Based on fast time simulation studies and expert judgement, a required punctuality of ±30s at the initial approach fix was assumed necessary. The feasibility of safely operating ACDA approaches with such arrival accuracy at TMA entry was demonstrated. In order to achieve this accuracy at the TMA entry points, a number of enablers were evaluated in the concept:
• Advanced arrival manager (AMAN) for accurate strategic planning of the CDA approaches and with specific additions for RNAV based sequencing.
• As a tactical support tool, a Converging Runways and Approaches Display Aid (CORADA) to assist executive controllers during sequencing and merging prior to the start of the CDA.
• Air-ground data-link communications to take into account available onboard data.
• Use of ASAS for merging and spacing, also during execution of the ACDA approach.
Isdefe Status: Approved Page 20/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
For some scenarios in the presented concept also FMS derived Estimated Time of Arrival was used for improving the arrival time estimates within the ground based AMAN planning, as well as delegated 4D guidance to the IAF by means of the onboard FMS Required Time of Arrival functions.
Objective 5-7 – Toulouse RTS feasibility assessment D7.3.1-1-CDA “A320 CDA Real Time Flight Simulation Report” (Ref. 11) summarizes the CDA operational test campaign performed on Airbus A320 flight simulator with equipment developed in the frame of OPTIMAL WP3 (FMS, displays and Flight Guidance). The objective of these tests was to assess the flyability of the studied CDA profiles, the technical feasibility of the cockpit changes as well as the pilot operational acceptance. The tests also permitted to prepare the flight test trials campaign.
Objective 6-8 – Toulouse Flight Trials
D7.4.1-1 “Toulouse Airport A320 CDA Flight Test Report” (Ref. 12) summarizes the CDA flight test performed with an A320 aircraft at Toulouse Blagnac airport with equipments developed in the frame of OPTIMAL WP3 (FMS, displays and Flight Guidance). The objective of these tests was to assess the flyability of the studied CDA profiles and verify the system performance as well as the pilot operational acceptance. The objective was also to check the acoustic benefits assessed in the environmental impact analysis.
Objective 9 – Bremen Flight Trials
D7.4.1-2 “Bremen Airport ATTAS CDA Flight Test Report” (Ref. 13) reports the flight trials that evaluated the CDA functions developed within OPTIMAL for DLR´s Advanced Flight Management System (AFMS). These functions allow flying an idle 4D ACDA in clean configuration until G/S intercept with an RTA given for the late merging point or at the threshold. The focus has been on the 4D performance. In addition, SBAS guidance performance has been assessed. 23 approaches to Bremen under various weather (wind) conditions have been carried out.
5.4 CONCLUSIONS Objectives 1 & 2 – Schiphol FTS Capacity simulations From the Schiphol capacity simulations it was found that the maximum arrival throughput is lowered introducing ACDA-procedures with the defined routing structure. The maximum throughput using ACDA-procedures attains 70 flights per hour. This is still within the operating standards of the potential future Schiphol 60-60 scenario (60 arrivals and 60 departures per hour).
When capacity limits are reached delay increases at a very high rate, due to the fact that many flights are propagated in the landing sequence (the ‘knock-on’ effect). Introducing ACDA-procedures under low traffic load the cumulative delay increases by 50%. This accounts for roughly 200 seconds of additional time per aircraft needed to perform a safe CDA compared to the current procedures. This time needs to be absorbed before entering the TMA. Under high traffic load the cumulative delay increases by 300%. This accounts for roughly 400 seconds of additional time per aircraft in peak-periods.
It is concluded that the decrease in maximum throughput and consequent increase in delay is caused by the larger separation values implemented at the merge point when introducing ACDA-procedures.
Isdefe Status: Approved Page 21/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Objective 3 – Schiphol Environmental impact analysis From the Schiphol environment assessment it was seen that the the ACDA approach results in a noise area reduction of 21% (LDEN48) and 10% (LDEN58) and a CO2 emission reduction of 12%. It was concluded that the implementation of optimised CDA approach and noise abatement distant take-off procedures may be converted in a traffic increase of 50% while maintaining environmental noise impact because:
• speed and altitude of the optimised CDA approach decrease constantly compared to conventional radar vectoring with altitude steps;
• the thrust setting of the aircraft when flying the ACDA approach flight profile is relatively low compared to level flying;
• the distant take-off reduces to less than climb-thrust at a lower altitude 800ft. Objective 3 – General Environmental impact analysis From the general environmental impact analysis it was concluded that CDA procedures have a positive noise impact both for single events and at airport scale:
• Nominal CDA procedure (with fixed vertical flight path) allow important noise savings above 3000ft compared to the baseline procedure due to both reasons: height profile optimization and no level segment at adapted thrust. This allows 6% to 35% reduction of the Lden exposure contours surfaces compared to baseline contours.
• Optimised CDA lead to important noise benefits (particularly for 55 and 60 dB Lden and 45 dB and 50 dB Lnight noise contours) for a generic large international airport. Indeed, it can result in 24% to 43% reduction on surface impacted at airport scale.
• Noise exposure contours mainly affected by the new procedures can be very different from one airport to another (depending on the number of movements) but the overall noise effects of the CDA concept are always beneficial.
Objective 4 – Schiphol RTS capacity and feasibility assessment The ACDA Real Time Simulations provided the following main results:
• The targeted arrival capacity of at least 30 CDA arrivals per hour / runway, as accepted in the initial requirements with ATC experts, was well achievable. A higher capacity (33-35 landings/hr or more) appears feasible based on further analysis of fast time safety and capacity simulations
• The use of CORADA in the TMA was well received to achieve the required safe separations prior to start of the CDA descent, The preferred setting of CORADA in the TMA is dual mode (contrary to the alternative master-slave mode).
• The application of CORADA in the extended TMA to achieve highly accurately metered arrivals in coordination with the AMAN provided mixed results. This is due to the inherent differences in operation between CORADA and AMAN. CORADA providing relative timing information, AMAN targeting an absolute arrival time schedule. On the one hand, arrival punctuality was generally lower compared to the other scenarios without the use of CORADA in the ETMA, on the other hand the participating controllers also indicated an overall better sequenced flow of traffic flow.
• Arrival punctuality was high with all combinations of enablers. During all conditions, the AMAN was rated positively as it provided useful and reliable information, a better understanding of the situation, and helped to plan and organise the runway landing sequence. As indicated above, the information provided to the executive controllers was sometimes confusing. The information provided by the AMAN for an absolute time
Isdefe Status: Approved Page 22/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
schedule versus that provided by CORADA, with relative guidance taking into account disturbances in the arrival flow.
• The use of RTA at the IAF combined with RNAV based path stretching provided a well-sequenced and spaced TMA entry with sufficient accuracy under the simulated conditions.
• From a flight deck perspective, the concept of RNAV based doglegs to improve the execution of the inbound planning, especially at the TMA entry point, was preferred above the current practice of vectoring: RNAV based descents provide a more predictable descent compared to vectoring based descents.
• The cockpit HMI should support flight crews in their tasks to monitor current aircraft status and anticipate aircraft behaviour ahead of time. In this context, the evaluated implementation of the cockpit HMI requires improvement with respect to the specifics of executing CDA’s, e.g. efficient presentation of configuration cues, monitoring of slow deceleration and clear annunciation of FMS profile updates during descent.
Objective 5-7 – Toulouse RTS feasibility assessment The CDA operational flight simulation campaign verified the flyability of the CDA profiles. The flight tests also demonstrated the feasibility of the cockpit changes required to fly these new profiles and verified the maturity of the systems developed for this function.
Regarding the crew feedback, the OPTIMAL CDA function was recognized easy to understand by most of pilots and in particularly, the nominal profile has been judged operationally acceptable by the pilots whereas the optimised CDA profile has been judged more complex. The crew workload was not increased compared to current operations. Some refinements and recommendations have been provided by the crew regarding the HMI developed specifically for the CDA function.
Objective 6-8 – Toulouse Flight Trials The flight trial confirmed the results of the Real Time Simulations. Again, the flyability of the CDA profiles was demonstrated. The crew workload was not increased compared to current operations; the guidance performance was satisfactory and no over-energy situation was encountered during the tests. The nominal profile has been judged operationally acceptable by the pilots; it has been considered as simple and intuitive and worth to be further studied whereas the optimised CDA profile has been judged complex. The concept of the optimised CDA profile is more difficult to understand and requires decelerating very early, which induces a longer deceleration and an increase of the flight time compared to classic approaches. Moreover, the flight trials confirmed the noise benefits assessed in the environmental analysis.
Objective 9 – Bremen Flight Trials In total at G/S intercept, an average accuracy of -2.2 seconds with a Sigma of 4.5 seconds has been achieved. At 500ft height above threshold, the average value was -4.5 seconds with a Sigma of 7.9 seconds. Taking only into account the 16 approaches with a good match between wind forecast and actual wind the 4D accuracy was about ±3 seconds.
Basically the trials have shown that
• ACDAs can be flown by the FMS to meet RTA on G/S intercept or even on RWY threshold which is one main enabler for implementing ACDAs using Late Merging Point Concept.
• Inaccurate wind forecast will either effect RTA accuracy or reduce noise benefits of ACDAs (e.g. if earlier flaps settings are required)
Isdefe Status: Approved Page 23/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Existing (GPS & GLONASS) core satellite constellations alone do not meet aviation’s strict requirements for Precision Approaches in terms of integrity, continuity, availability and accuracy values. To meet the operational requirements for various phases of flight, core constellations require augmentation, which can be obtained in three different ways:
• Ground Based Augmentation System (GBAS)
• Satellite Based Augmentation System (SBAS)
• Aircraft Based Augmentation System (ABAS)
Figure 2 GNSS Procedures
GBAS and SBAS use ground monitoring stations to verify the validity of satellite signals and calculate corrections to enhance GNSS performances. ABAS relies on avionics processing techniques or avionics integration. The following sections 6.1, 6.2 and 6.3 will describe the respective procedures based on these systems, the corresponding validation exercises and the conclusions.
6.1 APPROACH PROCEDURES BASED ON GBAS 6.1.1 Procedure overview
Within the context of the OPTIMAL project, only GBAS PA Straight-in Final Approach aligned with the runway centre line have been considered. However, offsets up to 5º are admissible. The Straight-in Final GBAS PA is based on GNSS information plus GBAS local corrections for both lateral and vertical guidance. An important advantage is the coverage of multiple runways with only one ground station, saving costs for airports (compared to xLS systems).
Final Approach Segment (FAS) Geometry is defined in the FAS Data Block and broadcast by the GBAS local station (VDB message). Once the VDB transmission is processed, the Path Identifier will be displayed, allowing manual cross-check against the chart by the crew.
An instrumental GBAS PA procedure is characterized by the ILS Look-alike term. This concept is understood in the way that the objective is to apply the GNSS (GBAS) technology in such way that modifications respect to conventional ILS approach procedures be minimized and make the “transition” affordable. The “transition” refers to an evolution
Isdefe Status: Approved Page 24/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
towards a future scenario in which the GNSS will be the “sole” navigation system mean, as recommended by ICAO:
• The flight crew displays are similar to the ones used in conventional ILS PA procedures, that is, simulating angular deviations which converge in the direction of the approach to the touchdown point.
• FAS Data Block contains all the information required for the definition of the Glide Path and the emulation of a converging guidance to the pilot whose sensibility increases in the approach direction.
• Obstacle assessment is based on the OAS, which are identical to ILS CAT I OAS. Within the context of OPTIMAL project, the rest of the segments involved in the procedure are also based on the RNAV concept and GNSS as positioning system (LNAV only)
At the same time, the OPTIMAL project considered that GBAS corrections are usable up to 4NM beyond the FPAP for the straight missed approach. That is, reversion from GBAS to other means of navigation should be performed before that limit. This criterion is derived from a combination of ICAO GBAS and FAA LAAS coverage criteria.
6.1.2 Validation objectives The following validation objectives were defined for the GBAS procedure:
1. Assess the impact of straight final GBAS approaches designed for the Málaga airport in terms of capacity (ATC workload, Delays, Nº of movements and Separation);
2. Assess the environmental impact of straight final GBAS approaches designed for the Málaga airport (noise nuisance);
3. Assess the operational safety of the proposed GBAS-PA approach procedure for RWY13 at Málaga airport;
4. Assess the overall flyability and performance of the GBAS procedure;
5. Obtain operational feedback on the GBAS procedure from pilots and ATCo;
6. Assess interoperability between Honeywell GBAS GS and Rockwell Collins MMR Airbus version;
7. Assess performance of the GBAS procedure in a different geographical environment than Toulouse with an obstacle rich environment.
Isdefe Status: Approved Page 25/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
6.1.3 Exercise Summary Objective 1 – Málaga capacity simulation D7.2-1 “Málaga Airport Capacity Simulation Results” (Ref. 14) summarizes the results of the Málaga Airport capacity study performed in a fast-time simulation using TAAM (Total Airport and Airspace Modeller), MWM (Multi Workload Model) and PITOT (Platform Integration Software).The results for the PA-GBAS procedure are summarised and analyzed in D6.3 “Validation Report” (Ref. 6).
Objective 2 – Málaga Environmental impact analysis D7.1.2-3 “Málaga Airport Environmental Assessment Data” (Ref. 15) gives the results of an environmental impact assessment with INM on and in the vicinity of the aerodrome of Málaga airport using PA-GBAS procedures. The results are summarized and analysed in D6.3 (Ref. 6).
Objective 3 – Málaga Safety Analysis D7.1.1-2 “Operational Safety Assessment of GBAS and SBAS Flight Trials” (Ref. 16), identifies the operational hazards that might arise from the proposed GBAS-PA approach procedure for RWY 13 at Málaga Airport, evaluates the significance of the risks associated with those hazards, identifies measures that might be adopted to mitigate those risks and, ultimately, determines whether or not the proposed procedure would provide for an adequate level of safety.
The safety assessment for the straight-in final GBAS-PA approach procedure for RWY 13 at Malaga airport consists of:
• Functional Hazard Assessment (FHA) – identifying hazards, analysing their severity and setting safety objectives in terms of the maximum tolerable frequency of hazards.
• Preliminary System Safety Assessment (PSSA) – analysing the causes of hazards and developing safety requirements that enable the safety objectives to be met.
Objective 4&5 – Málaga Beechcraft Flight Trials D7.4.2-1 “Malaga Airport GBAS CAT I Straight-in Flight Test Report” (Ref. 17) contains the description and analysis (technical and operational) of six GBAS CAT I Straight-In approaches to Málaga airport (RWY 13).
The flight tests were performed under Visual Meteorological Conditions (VMC) and with two pilots onboard (Test pilot and observer).
Objective 6&7 – Málaga A320 Flight Trials D7.4.2-3 “Malaga Airport A320 GBAS CAT-I Flight Test Report” (Ref. 18) summarizes the results of the GBAS flight tests with an Airbus A320. It was chosen to test the Airbus airborne GBAS solution more thoroughly by means of using another GBAS manufacturer, in a different geographical environment than Toulouse. To this end Aena´s GBAS Ground station from Honeywell, installed at Malaga Airport with an obstacle rich environment, was used. The main objective of the test was to verify the interoperability between the Rockwell Collins MMR versioned for Airbus and the latest Honeywell GBAS GS prototype.
Airbus flight test crew performed several manual and automatic (including auto-land) approaches with touch and go. This test also included an IBERIA pilot flying two GLS approaches.
Isdefe Status: Approved Page 26/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
6.1.4 Conclusions Objective 1 – Málaga capacity simulation The results of the Málaga airport capacity simulation in terms of ATC workload, separation, delay and number of movements are summarized and analysed in D6.3 (Ref. 6). It is concluded that the straight-in procedures can manage efficiently the expected 2010 arrival demand and increase or at least maintain the maximum number of operations while maintaining delays at an acceptable level. In addition, the straight-in procedures can reduce the ATCo’s workload along the day due to elimination of vectoring and the correspondent communications controller-pilot.
Objective 2 – Málaga Environmental impact analysis The results of the Málaga environmental impact analysis are summarized in D6.3 (Ref. 6). It is concluded that although the altitude for the straight-in procedure is lower than the baseline one, the noise contour for the straight-in procedure is slightly smaller than the baseline one, due to the better horizontal guidance. In addition, there is a reduction in the affected population during the day and during the night.
Objective 3 – Málaga Safety Analysis After identifying and assessing the conflict scenarios of the proposed approach procedure for Malaga airport it was concluded that the majority of the conflicts are situated in the acceptable or tolerable (minimum safety objective) area. However, there were two conflict scenarios classified as unacceptable, both related to situations where the hazard is not detected:
• Aircraft glide slope overshoot. The aircraft does not capture the glide slope, overshooting the nominal descend path. Then, the aircraft tries to regain nominal path, with a subsequent increase in descend rate. This situation can lead to various effects, such as an unstable approach, or even a Go-Around.
• Aircraft flies a wrong path. The aircraft flies an incorrect procedure or descend path in the final segment due, for example, to corrupt or wrong FAS data or correction data.
For these two conflict scenarios the safety requirements and candidate mitigation actions were identified and classified according to the domain and the sub domain where they are involved, see Ref. 16.
Objective 4: Flyability and Performance during Málaga Beechcraft Flight Trials The following conclusions were drawn from the flight trials:
• Very small values in Navigation system Errors were achieved, indicating that the navigation trajectory built from the onboard GBAS receiver real time data does not differ much from the actual trajectory computed by an independent accurate DGPS post-processing.
• Maximum error values remain around two meters for the complete fight and around one meter along the approaches. Protection Level values provided by the onboard MMR (Multi Mode Receiver) cover this Navigation System Errors in both components, horizontal and vertical.
• The provided Protection Level values stayed under Alert Limits in all the approach parts of the flight, accomplishing availability requirements defined for CAT-I procedures.
Isdefe Status: Approved Page 27/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
• Taking into account the strong presence of wind and seasonal operational limitations, Flight Technical Error values are considered reasonable.
• The GBAS on–ground station was working properly during the flight trials. In addition the onboard MMR behaved reasonably well, just remarking the quite high amount of lost messages which even did not affect the proper functioning of the receiver.
Objective 5 – Operational point of view from Málaga Beechcraft Flight Trials Both pilots and ATCOs have a very good impression of the system and its capabilities. The pilots emphasized the smoothness of the guidance system compared to ILS. The ATCo´s stated that since the number of communications was reduced and the radar vectoring simplified, the ATC workload seemed reduced.
Objective 6&7 – Málaga A320 Flight Trials The flight tests showed full interoperability between airborne part and ground part of the GLS system. GBAS Performance on Airbus A/C has been demonstrated to be on the order of 1 meter in lateral and vertical, in various conditions, paving the way for future Cat II/III operations after successful GBAS Cat I implementation and deployment.
It was concluded that GBAS offers a very smooth signal for guidance and pilots, and exhibits a very good performance with low susceptibility to external multipath. This makes it suitable for future auto-land operations in VMC with less separation between A/C. In addition, ILS look-alike cockpit design scheme offers another Precision Approach means with limited additional crew training.
6.2 APPROACH PROCEDURES BASED ON SBAS 6.2.1 Procedure overview
Within the context of the OPTIMAL project, only APV/SBAS Straight-in Final Approach aligned with the runway centre line have been considered. However, offsets up to 5º are admissible.
The straight-in Final SBAS/APV Approach is based on SBAS positioning information for both lateral and vertical guidance.
Final Approach Segment (FAS) Geometry is defined in the FAS Data Block and contained in the onboard data base.
An instrumental APV procedure is characterized under the ILS Look-alike concept. This concept should be understood in the way that the objective is to apply the GNSS (SBAS) technology in such a way that modifications respect to conventional ILS approach procedures be minimized and make the “transition” affordable. The “transition” refers to an evolution towards a future scenario in which the GNSS will be the “sole” navigation system mean, as recommended by ICAO:
• The flight crew displays are similar to the ones used in conventional ILS PA procedures, that is simulating angular deviations which converge in the direction of the approach to the touchdown point;
• FAS Data Block contains all the information required for the definition of the Glide Path and the emulation of a converging guidance to the pilot whose sensibility increases in the approach direction.
Isdefe Status: Approved Page 28/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Obstacle assessment is based on APV OAS, which are derived from ILS OAS, taking into account that:
• Lateral guidance is considered to have LLZ performance;
• Vertical clearance is more restrictive than the PA CAT I case. Within the frame of OPTIMAL project, the rest of the segments involved in the procedure are also based on the RNAV concept and SBAS as positioning system (LNAV only)
6.2.2 Validation objectives The following validation objectives were defined for the SBAS procedure:
1. Assess the impact of straight final SBAS approaches designed for the San Sebastian airport in terms of capacity (ATC workload, Delays, Nº of movements and Separation);
2. Assess the environmental impact of straight final SBAS approaches designed for the San Sebastian airport (noise nuisance);
3. Identify the operational hazards that might arise from the proposed SBAS-APV approach procedure for RWY 04 at San Sebastian Airport;
4. Perform a detailed cost-benefit analysis for the introduction of SBAS in San Sebastian airport;
5. Assess the overall flyability and performance of the SBAS procedure;
6. To obtain operational feedback on the SBAS procedure from pilots and ATCo.
2 San Sebastian Analytical INM Environment Noise AEN
3 San Sebastian Analytical Methodology Hazard
Identification AEN
4 San Sebastian Analytical Methodology Cost Benefit ISD
5,6 San Sebastian Flight Trial Beechcraft
Flyability Performance Operational
AEN
Table 4 Overview of SBAS Validation exercises
6.2.3 Exercise Summary Objective 1 – San Sebastian capacity simulation D7.2-2 “San Sebastian Airport Capacity Simulation Results” (Ref. 19) AENA summarizes the capacity simulation of the SBAS approaches to RWY22 of San Sebastian Airport. The study was performed as a fast-time simulation using TAAM (Total Airport and Airspace Modeller), MWM (Multi Workload Model) and PITOT (Platform Integration Software). The exercises are summarised in D6.3 “Validation Report” (Ref. 6).
Isdefe Status: Approved Page 29/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Objective 2 – San Sebastian Environmental impact analysis D7.1.2-4 “San Sebastian Airport Environmental Assessment Data” (Ref. 20) gives the results of an environmental impact assessment with INM on and in the vicinity of the aerodrome of San Sebastian airport. The environmental impact analysis is summarized in D6.3 (Ref. 6).
Objective 3 – San Sebastian Safety Analysis D7.1.1-2 “Operational Safety Assessment of GBAS and SBAS Flight Trials” (Ref. 16), identifies the operational hazards that might arise from the proposed SBAS-APV approach procedure for RWY 04 at San Sebastian Airport, evaluates the significance of the risks associated with those hazards, identifies measures that might be adopted to mitigate those risks and , ultimately, determines whether or not the proposed procedure would provide for an adequate level of safety.
More specifically, the safety assessment for the SBAS-APV approach procedure for RWY04 at San Sebastian airport consists of:
• Functional Hazard Assessment (FHA) – identifying hazards, analysing their severity and setting safety objectives in terms of the maximum tolerable frequency of hazards;
• Preliminary System Safety Assessment (PSSA) – analysing the causes of hazards and developing safety requirements that enable the safety objectives to be met.
Objective 4 – San Sebastian Cost Benefit Analysis D7.1.4 “San Sebastian SBAS Cost-Benefit Analysis” (Ref. 21) analyses the costs and benefits for all actors involved for the case of implying APV SBAS procedures in San Sebastian Airport.
The rationale behind the CBA is the following. The operational runways of San Sebastian Airport have currently Non-Precision Approach (NPA) procedures. Due to topographical constraints it is also impossible to install ground-based navaids for Precision Approach procedures, e.g. ILS. Therefore the use of APV SBAS procedures will significantly improve the accessibility of San Sebastian Airport and the safety levels because of its vertical guidance capabilities.
Objective 5&6 – San Sebastian Flight Trial Beechcraft D7.4.2-2 “San Sebastian Airport SBAS APV Flight Test Report” (Ref. 22) contains the description and analysis (technical and operational) of four manually flown SBAS LPV Straight-In approaches to San Sebastian airport (RWY 04).
The flight test were performed under Visual Meteorological Conditions (VMC) and with two pilots onboard (Test pilot and observer).
6.2.4 Conclusions Objective 1 – San Sebastian capacity simulation The results of the San Sebastian airport capacity simulation in terms of ATC workload, separation, delay and number of movements are summarized and analysed in D6.3 (Ref. 6). It is concluded that the straight-in procedures can manage efficiently the expected 2020 arrival demand and maintain the maximum number of operations without a significant increase in delays 2, 3. In addition, the straight-in procedures can keep the ATCo’s workload
2 San Sebastian Airport has difficult weather conditions, so current operational minima of the non-precision approach procedures are clearly limiting the airport accessibility, capacity and safety of the approach. Therefore, the capacity assessment should be accompanied by an accessibility analysis.
Isdefe Status: Approved Page 30/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
far from the saturation limit due to elimination of vectoring and the correspondent controller-pilot communications.
Objective 2 – San Sebastian Environmental impact analysis The results of the San Sebastian environmental impact analysis are summarized in D6.3 (Ref. 6). It is concluded that the straight-in approach procedure flies at lower altitude than the baseline so, the noise contours further away from the runway threshold are slightly bigger for the straight-in than for the baseline scenario. Nevertheless, the noise footprint area decreases in the vicinity of the airport owing to the accuracy provided by SBAS in the new procedures allowing to fly closer to the nominal path.
In addition, there is a slight reduction in the affected population during the day and no change in the affected population during the night.
Objective 3 – San Sebastian Safety Analysis After identifying and assessing the conflict scenarios of the proposed approach procedure for San Sebastian airport it was concluded that the majority of the conflicts are situated in the acceptable or tolerable (minimum safety objective) area. However, five conflict scenarios could be classified as unacceptable, all of them related to situations where the hazard is not detected:
• Aircraft/High terrain conflict (Initial Segment). This conflict occurs when an aircraft deviates from the intended flight path, flying close to high terrain.
• Aircraft/High terrain conflict (Medium Segment). Same conflict scenario as for Initial segment but the effects of these conflicts are more critical than in Initial Segment, since the aircraft flies closer to the ground
• Aircraft/High terrain conflict (Final Segment). The effects of this conflict are the most severe ones.
• Aircraft Glide slope overshoot. The aircraft does not capture the glide slope, overshooting the nominal descend path. Then, the aircraft tries to regain nominal path, with a subsequent increase in descend rate. This situation can lead to various effects, such as an unstable approach, or even a Go-Around.
• Aircraft flies a wrong path. The aircraft flies an incorrect procedure or descend path in the final segment due, for example, to corrupt or wrong FAS data or correction data.
The high severity of the conflict scenarios is mainly due to the topography of the surroundings of San Sebastian airport, with abrupt mountains in the initial and medium segments and buildings and antennas near the threshold of RWY 04.
For the above mentioned conflict scenarios the safety requirements and candidate mitigation actions were identified and classified according to the domain and the sub domain where they are involved, see Ref. 16.
3 Nowadays the baseline scenario for RWY04 is not used for IFR approaches due to operational restrictions from airlines. Therefore, all results obtained for the straight-in approach procedures should be considered as a global improvement without comparing them with a baseline scenario. In addition, it should be taken into account that a significant reduction of flight time will be obtained with respect to the current airport operation (baseline RWY 22).
Isdefe Status: Approved Page 31/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Objective 4 – San Sebastian Cost Benefit Analysis It is concluded that introducing SBAS at San Sebastian Airport is, from an economical point of view, a beneficial operation. The initial investment costs for the airlines are negligible compared to the expected benefits owing to flight time and disruption reduction. The initial investment for the Airport operator and ANSP will result in an airport that can offer a much higher service level to its clients (airlines), which will most probably result in a considerable increase in traffic to San Sebastian. Unfortunately, this benefit is not quantifiable at the moment.
Objective 5 – Flyability and performance during San Sebastian Flight Trial Beechcraft The following conclusions were drawn from the flight trials:
• The SBAS LPV approach performance analysis showed very good Navigation System Errors computed with the onboard experiment platform.
• The computed Protection Levels stayed under the Alert Limits defined for the procedure during the whole flight and hence the SBAS APV service was always available for the performed LPV approaches.
• The Flight Technical Error values are considered reasonable. The second approach includes the highest FTE (almost 700 meters) values due to the heavy wind conditions.
Objective 6 – Operational point of view from San Sebastian Flight Trial Beechcraft
• The approach procedure resulted easy to follow in terms of aircraft manoeuvring and the pilots did not find any difficulties in following the vertical profile. Actually, the smoothness of the guidance system was underlined. The pilots pointed out the reduction in workload comparing with flying an entirely non-precision approach.
• The controllers highlighted that the provision of vertical guidance would increase the number of pilots who accepted this specific approach to RWY04 at San Sebastian airport, thus facilitating the operations and decreasing the workload of both pilots and controllers. However, some training on satellite-based flight operations would be highly appreciated.
6.3 APPROACH PROCEDURES BASED ON ABAS 6.3.1 Procedure overview
A straight-in final LPV approach procedure is an instrument approach procedure that is provided, within the final approach phase, with lateral and vertical guidance, that does not meet the performance requirements established for Precision Approach operations. So it cannot be classified as a conventional Precision Approach (PA).
The LPV procedure is based on the RNAV concept. It is characterized by the ILS look-alike concept that consists in minimizing differences with conventional ILS approach procedures. The final approach segment is identical to an ILS PA. It is aligned (potentially with an offset) with the runway centreline and measures at least 4NM. From an operational stand point, it finishes at the Decision Altitude/Height (DA/H) where the pilot must determine whether visual references are on sight in order to decide to continue the approach procedure or to perform a missed approach procedure. ABAS provides lateral and vertical guidance.
6.3.2 Validation objectives The following validation objectives were defined for the ABAS procedure:
1. Measure the performance of a new hybridisation algorithm.
Isdefe Status: Approved Page 32/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
6.3.3 Exercise Summary Objective 1 – Toulouse Flight Trials D7.4.5-1 “Toulouse Airport A320 Autonomous FLS Flight Test Report” (Ref. 23) summarizes the flight tests performed on Toulouse airport with an A320 aircraft instrumented with an autonomous ABAS system. The system was based on an enhanced THALES MMR (with improved GPS data processing) and a new hybridisation algorithm from Northrop Grumman called Precision AIME and implemented in a specific ADIRU (based on LTN 101 E). Applying this “Performance Based” concept, an RNAV GPS published approaches with LPV minima could be flown with ABAS.
The performances of the hybridisation algorithm have been assessed thanks to DGPS trajectography during the flight test.
6.3.4 Conclusions Objective 1 – Toulouse Flight Trials The results demonstrated a good execution of initialisation of PrAIME in real condition starting from a known position stored in the database and a good functioning of hybridisation algorithm during the entire flight. It was concluded that the ABAS equipments had the capability for APV I approaches and showed values close to APV II approach criteria.
Isdefe Status: Approved Page 33/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
7.1 PROCEDURE OVERVIEW The ICAO Performance Based Navigation (PBN) Manual has defined two types of approaches called RNP and RNP AR, from which the latter requires a specific approval (AR), in terms of aircraft capability, crew training, etc.
RNP AR Approaches4 are based on the Area navigation concept, which permits aircraft operation on any desired flight path within the coverage of station-referenced navigation aids or within the limits of the capability of self-contained navigation aids, or a combination of these. The requirements placed on the area navigation system include:
• The performance being required of the area navigation system in terms of accuracy, integrity, continuity and availability;
• The functions that need to be available in the area navigation system so as to achieve the required performance;
• The navigation sensors, integrated into the area navigation system, that may be used to achieve the required performance;
• Flight crew and other procedures needed to achieve the performance being required of the area navigation system.
Navigation specifications which require on-board performance monitoring and alerting are termed RNP specifications. It addresses the Total System Error (TSE), encompassing the three main errors, which are Path Definition Error (PDE), Flight Technical Error (FTE), and Navigation System Error (NSE), as shown in the figure below.
Total System Error (TSE)
Estimated Position
Path Definition Error (PDE)
Flight Technical Error (FTE)
Navigation System Error (NSE)
Figure 3: Definition of error terms for RNP-AR approaches
The main benefits of RNP AR approach operations are :
• An improved accessibility in obstacle rich environment;
• Lower minima with instrument approach replacing circling or visual approach;
• The avoidance of populated areas, therefore an environmental benefit.
4 in most of OPTIMAL documentation, the term RNP-RNAV is used instead of RNP AR as this was the current terminology at the time of the project.
Isdefe Status: Approved Page 34/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Initially, three types of RNP-AR approach procedures were to be developed during the OPTIMAL project:
• Straight-in procedures
• Curved procedures
• Segmented procedures. However, during the course of OPTIMAL, the flyability of segmented approaches was questioned and the latest development of the ICAO PBN manual finally discarded their use OPTIMAL therefore changed the objectives concerning RNP-AR procedures and decided to not promote Segmented Final Approach Procedure. The following sub-sections give an overview of the straight-in and curved procedures.
7.1.1 Straight-in RNP AR approach procedures Within the context of the OPTIMAL project, a procedure is considered as Straight-in Final Approach when the Final Approach Segment (FAS) is aligned with the runway centreline. The initial, intermediate and missed approach segments are based on RNP-AR (Lateral guidance only). For the Final Approach Segment, two variants are proposed:
• RNP(AR) lateral. Vertical guidance is based on Baro-VNAV (VEB)
• RNP(AR) lateral and vertical.
7.1.2 Curved RNP AR approach procedures Within OPTIMAL, a curved final approach procedure is a procedure involving a fixed radius leg on the final approach segment. The roll-in waypoint is the Final Approach Fix and the roll out waypoint is located at the runway centreline at a distance closer than 4NM from the threshold.
Special attention was paid to the so called hybrid approaches. These approaches start as RNP AR approaches, followed by a transition to an xLS landing; (xLS stands for ILS, MLS, GLS, FLS)
According to the kind of guidance of the last leg of the approach, the classification of curved RNP approach procedures is as follows:
• An RF leg and a short aligned leg, both RNP-AR (AR) with vertical guidance based on Baro-VNAV (VEB).
• An RF leg and a short aligned leg, both with lateral and vertical RNP guidance.
• An RNP-AR (AR) RF leg with vertical guidance based on Baro-VNAV (VEB) plus a short xLS leg.
• An RF leg with lateral and vertical RNP guidance plus a short xLS leg.
In the implementation options 3 and 4, it is recommended that the transition from xLS to RNP is automatic as soon as the Missed Approach is engaged.
Isdefe Status: Approved Page 35/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
7.2 VALIDATION OBJECTIVES The following validation objectives were defined for the RNP-AR procedure:
1. Assess the impact of curved RNP-AR approaches designed for the Málaga and San Sebastian airport in terms of capacity (ATC workload, Delays, Nº of movements and Separation);
2. Assess the environmental impact of curved RNP-AR approaches designed for the Málaga and San Sebastian airport (noise nuisance);
3. Assess the impact of the introduction of curved RNP-AR procedures at Málaga airport on approach and tower controllers (safety aspect);
4. Assess the flyability and pilot acceptance of curved RNP-AR with transition to ILS final approach procedures to the Málaga and San Sebastian airports
5. Assess the overall performance and flyability of the curved RNP-AR and RNP-xLS (hybrid) approach procedures (incl. the new cockpit functions) for several simulated airport scenarios;
6. Assess operational pilot acceptance of new airborne functions to fly RNP AR and RNP-xLS approaches, especially the RNP-xLS hybrid procedures;
7. Provide sufficient evidence to support the argument that curved RNP-AR approaches will be acceptably safe.
Isdefe Status: Approved Page 36/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
7.3 EXERCISE SUMMARY Objective 1 – Málaga / San Sebastian capacity simulation D7.2-1 “Málaga Airport Capacity Simulation Results” (Ref. 14) and D7.2-2 “San Sebastian Airport Capacity Simulation Results” (Ref. 19) summarize the capacity simulation of the curved RNP-AR approaches to respectively RWY31 of Málaga Airport and RWY22 of San Sebastian Airport. The study was performed as a fast-time simulation using TAAM (Total Airport and Airspace Modeller), MWM (Multi Workload Model) and PITOT (Platform Integration Software). The exercises are summarized and analysed in D6.3 “Validation Report” (Ref. 6).
Objective 2 – Málaga / San Sebastian Environmental impact analysis D7.1.2-3 “Málaga Airport Environmental Assessment Data” (Ref. 15) and D7.1.2-4 “San Sebastian Airport Environmental Assessment Data” (Ref. 20) give the results of an environmental impact assessment with INM on and in the vicinity of the aerodrome of respectively Málaga and San Sebastian airport. The environmental impact analyses are summarized and analysed in D6.3 (Ref. 6).
Objective 3 – Malaga IANS Tower Safety Analysis D7.3.2-2 “Malaga real-time safety-oriented simulation for curved approach procedures” (Ref. 24) EEC presents the results obtained from a safety-oriented real time simulation that was conducted on the airspace controlled by Malaga controllers. The goal was to assess the impact on safety of the introduction of curved approach procedures, with a today’s level of traffic and with 2010 forecast traffic, all mixing new and current procedures.
The results, that mostly concern ground feasibility, come from feed backs from the controllers and from expert observations during the different exercises that were run.
Objective 4 – Málaga / San Sebastian RTS feasibility assessment D7.3.2-1 “RNAV Curved/Segmented Approach Procedures with Transition to ILS Flight Simulation Report” (Ref. 25) describes the flight simulation sessions for the curved RNP-AR with transition to ILS final approach procedures to the Málaga and San Sebastian airports. The simulations were performed using A320/A340 crew training six axis full flight simulators. The qualitative assessments were focused on flyability and operational aspects. More specifically, the objectives were to:
• assess the feasibility to reduce the Final Approach Segment length to save flight time and improve the landing manoeuvre efficiency;
• assess the transition from non aligned final segment to ILS taking into account the flyability point of view;
• assess the flyability and the pilot acceptance of the Curved/Segmented procedures;
The curved/segmented final approach procedures were compared either with ILS cat I or “GBAS/SBAS “Straight-In approach procedures.
Objective 5&6 – Toulouse and Nice RTS feasibility assessment D7.3.1-1-RNP “A320 Low RNP Real Time Flight Simulation Report” (Ref. 26) summarizes the assessment of the OPTIMAL RNP function and procedures.
Isdefe Status: Approved Page 37/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Objective 5&6 – Feasibility during Toulouse Flight Trial D7.4.4-1 “Toulouse Airport A320 Low RNP Flight Test Report” (Ref. 27) summarizes the Flight trial with an A320 aircraft performing RNP-AR and hybrid RNP-AR-xLS approaches at Toulouse Blagnac airport with equipments developed in OPTIMAL WP3 frame.
The purpose was to assess several aspects of the OPTIMAL RNP function:
• General RNP usability and impact on current pilot’s tasks.
• RNP usability according to different conditions (AP ON or OFF, RF legs…).
• RNP transitions (change of RNP level, transition to xLS).
• RNP HMI Display (need, location, relevance…)
• Alerting mechanization.
• Missed approach.
The flight confirmed the capability of respecting RNP values, coded on the OPTIMAL NDB or manually entered: RNP 0.3, RNP 0.2 and RNP 0.15 Nm for RNP-AR procedures, RNP 0.15 Nm for RNP/ILS ones.
Various approaches were flown, in AP ON mode, AP OFF and with RNP/ILS transitions. For each one of the approach, RNP parameters and symbologies could be observed on ND and PFD and on modified MCDU pages.
Objective 7 – Generic hazard identification D7.1.1-1 “Curved Approaches Preliminary Safety Case” report (Ref. 28) presents a structured analysis of the safety of curved approach operations using the ICAO RNP-AR APCH specification, considering both fault free and failure conditions.
7.4 CONCLUSIONS Objective 1 – Málaga capacity simulation The results of the Málaga airport capacity simulation in terms of ATC workload, separation, delay and number of movements are summarized and analysed in D6.3 (Ref. 6). It is concluded that the owing to the introduction of the curved final RNP AR procedures the maximum number of arrivals per hour will increase significantly, while the delays do not increase. In addition, the ATCo’s workload is reduced due to elimination of vectoring and the correspondent communications controller-pilot.
Objective 1 – San Sebastian capacity simulation The results of the San Sebastian airport capacity simulation in terms of ATC workload, separation, delay and number of movements are summarized and analysed in D6.3 (Ref. 6). It is concluded that the curved approach procedures can manage efficiently the expected 2020 arrival demand and maintain the maximum number of operations. The total delays increase significantly, but the average delay of the delayed aircraft (a flight is considered as delayed when its delay is higher than 3 minutes) is reduced or at least maintained. In addition, the ATCo’s workload is reduced due to elimination of vectoring and the correspondent communications controller-pilot.
Isdefe Status: Approved Page 38/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Objective 2 – Málaga Environmental impact analysis The results of the Málaga environmental impact analysis are summarized in D6.3 “Validation Report” (Ref. 6). It is concluded that the noise contours further away from the runway threshold (40dB and 45dB) are larger for the curved RNP-AR procedures than for the baseline procedures, due to the lower altitude profiles of the new procedures. Nevertheless, the noise footprint area decreases in the vicinity of the airport given that the accuracy provided by RNP-AR allows to fly closer to the nominal path. Therefore, there is a significant reduction in the affected population during the day (Lden) and a slight reduction during the night (Lnight).
Objective 2 – San Sebastian Environmental impact analysis The results of the San Sebastian environmental impact analysis are summarized in D6.3 “Validation Report” (Ref. 6). It is concluded that since the curved RNP-AR approach is flown at a lower altitude than the baseline during the final segment of the approach, the noise contours are slightly larger than for the baseline scenario, increasing the affected population.
Objective 3 – Malaga IANS Tower Safety Analysis The results of tactical control, reliability and complexity metrics were summarized in D6.3 “Validation Report” (Ref. 1).
It is concluded that the curved final RNP AR procedure simulation showed a negative impact on the safety metrics. More studies, in particular longer real-time simulation involving more different controllers, better trained to work with RNAV procedures, seem necessary to better assess the impact of the new procedures.
Objective 4 – Málaga and San Sebastian RTS feasibility assessment The flight simulation sessions for the curved RNP-AR with transition to ILS final approach procedures to the Málaga and San Sebastian airports showed:
• From a flyability point of view, 200ft seems to be a ”correct” DH that could be applied and does not need to be increased.
• Reducing the Final Approach Segment in the Curved approach Procedures (4, 3, 2 NM) does not result in operational problems for the pilots.
• Aircraft need to be properly configured (landing gear out & intermediate flap settings) before the FAF. Delayed configuration resulted in an increase in the pilot workload.
• According to the pilots no new phraseology is required to perform curved final approach procedures and no understanding problems occurred with respect to the procedures charts.
Objective 5&6 – Toulouse and Nice RTS feasibility assessment The following conclusions were drawn from the RNP-AR real time flight simulations:
• The OPTIMAL RNP function was recognized by most pilots as a very efficient way to monitor the performance of the aircraft with regards to the required performance throughout the RNP-AR approach procedure;
• The crews has no difficulty to fly the RNP-AR and the hybrid RNP-AR to ILS approaches, using the OPTIMAL design;
• The possibility to perform hybrid approaches (RNP-AR then ILS) with automatic mode transitions was found very promising by most pilots;
Isdefe Status: Approved Page 39/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
• Keeping the managed navigation mode engaged in case of an RNP-AR coded missed approach was considered by all pilots as very beneficial, limiting reaction time and thus improving safety;
• The A320 aircraft simulator was always able to meet the required performance, even with turns (radius to fix legs) close to the runway threshold in strong tail wind conditions.
Objective 5&6 – Feasibility during Toulouse Flight Trial Globally, the RNP function was operationally much appreciated, especially the possibility to perform hybrid approaches, i.e. RNP-AR approaches with an automatic transition to ILS. Some comments were done, mainly on the alerting mechanisation: the crew recommends not to trigger a triple-click in case of RNP loss, and would prefer a de-correlation of the navigation and guidance monitoring and alerting mechanisation.
Objective 7 – Generic hazard identification The principal argument addressed in this document is that ‘RNP-AR based curved approaches have been specified to be acceptably safe’. In the context of this report, ‘acceptably safe’ is defined as the risk of an accident being no greater than current similar operations and reduced as far as reasonably practicable.
In addressing the top level claim the sub-arguments have been addressed as follows:
Arg1.1. The concept underlying curved approaches is intrinsically safe The intrinsic safety of curved approaches is dependant on correct procedure design and achieving a containment excursion frequency no greater than 10-7 per approach. Given that the RNP AR APCH specification is defined as a means to achieve the target, evidence to support the argument will be presented as part of the aircraft certification and operational approval process. However a number of procedure design issues remain which need to be resolved, and further supporting evidence could be gained through the development of a model similar to the ILS Collision Risk Model.
Arg1.2. The design of the system is complete and correct The boundary of the concept has been clearly defined; however specification of the xLS transition and straight-in leg stabilisation distances is not yet complete. Safety requirements have been derived to eliminate the chance of hazardous situations arising under fault-free conditions. The interaction between safety nets and curved approaches has been assessed, resulting in a requirement to enhance EGPWS effectiveness for individual approaches.
Arg1.3. The system design functions correctly and coherently under all expected conditions Real time simulations have been conducted to analyse Controller reaction to curved approaches. The results indicate that there are some issues regarding Controller detection of deviations once an aircraft is cleared for an AR approach, especially in the vertical plane, and sequencing and separation errors in a mixed AR mode environment. Airbus have also carried out a series of real time simulations and flight tests to investigate, inter alia, the dynamic behaviour of aircraft systems and the coherency of flight deck tasks, e.g. the transition from RNP AR to xLS and the transition from Final Approach to Missed Approach. Some detailed recommendations for further study and potential system enhancements were identified; however overall Pilot feedback was very positive with general acceptance of the concept.
Isdefe Status: Approved Page 40/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Arg1.4. The system design is robust against external abnormalities Sufficient evidence has been provided to show that the system is robust against all identified external failures and abnormalities.
Arg1.5. All risks from internal system failure have been mitigated successfully All reasonably foreseeable hazards have been identified and risk assessed. A risk balance has been carried out against straight-in RNP 0.3 approaches and NPAs indicating what are the main risk drivers. Compared to straight-in RNP 0.3 approaches there are potential risk increases and decreases; there are some generic issues which are open and local factors also need to be accounted for in determining the net risk delta. Compared to NPAs, there is potential for these approaches to offer overall risk benefits.
Arg1.6. All that has been specified in support of the safety assessment is realistic The safety requirements derived are verifiable and have been shown to be capable of being satisfied in a typical implementation. Evidence has also been provided to show that all assumptions are necessary and valid. As noted in the section on intrinsic safety, the fault free accuracy requirements are an open issue that require more evidence to support their practicability.
Isdefe Status: Approved Page 41/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
8.1 PROCEDURE OVERVIEW At the end of the 90's a landing procedure called HALS/DTOP was developed in cooperation by the Frankfurt Airport AG and the Deutsche Flugsicherung GmbH (DFS – German Air Navigation Services) for the Frankfurt Airport. The objective of the work done in the frame of the OPTIMAL project is to describe how a second threshold on a runway can be operated, which benefits can be expected and which restrictions have to be considered under the different conditions of a single runway airport or a parallel runway system. The basic idea of a displaced or dual/displaced threshold is the invention of a second threshold on a long runway at least 1500m from the original one, so that the displaced glide slope is approximately 260ft above the other, resulting in a reduced wake vortex landing separation.
Figure 4 Displaced threshold approach on a dependent runway system
8.2 VALIDATION OBJECTIVES The following validation objectives were defined for the DT procedure:
1. Show that the procedure can enhance the throughput of arrival traffic at congested airports without sacrificing too much of the potential departure traffic throughput on the RWY system;
2. Show that additional workload for approach controllers is manageable;
3. Assess the additional benefit of advanced planning systems, both for the throughput of arrival traffic and for the ATC workload.
Table 7 shows the DT exercises that were performed in order to meet the above mentioned objectives.
Isdefe Status: Approved Page 42/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
8.3 EXERCISE SUMMARY Objective 1-3 – Frankfurt RTS capacity and feasibility assessment D7.3.4-1 “Results of Frankfurt DT simulations” (Ref. 29) gives the results of the capacity- and workload-oriented real time simulations on the Radar Simulator ATMOS at DLR-Braunschweig for the 'dual threshold' approach procedure on a parallel runway system. The exercise and the results are summarized and analysed in D6.3 (Ref. 6). Additional to the validation objectives mentioned in 8.2, the influence of additional departures and portion of “heavy” within the arrival demand was evaluated.
8.4 CONCLUSIONS Objective 1-3 – Frankfurt RTS capacity and feasibility assessment The results showed that the introduction of Dual Threshold Operations (without AMAN) resulted in:
• An increase of arrival traffic capacity;
• No significant increase of controller (approach) workload;
• An increase in ATCO-Pilot Communications;
• A decrease of departure capacity.
Introducing the advanced AMAN and ADCO planning systems resulted in:
• No significant decrease of controller workload;
• A decrease in ATCO-Pilot Communications;
• A compensation of the departure capacity drop down;
• An increase of arrival and departure efficiency and an increase of departure predictability.
It is concluded that with DT operation a significant increase of arrival traffic throughput at congested airports due to a reduced separations can be obtained while the ATCo workload not significantly changes. Furthermore it is concluded that advanced planning systems (AMAN and ADCO) are beneficial for Displaced Threshold Operations
It is however remarked that the results cannot be used for generalized quantitative statements, due to the following reasons:
• Only one arriving traffic scenario has been used which has been split into two by modifying only the ratio of aircraft with WTC “heavy” (20/40%);
• Only three controller teams have taken part in the simulations;
• In addition the familiarization of the teams with high traffic loads was on a very different level due to the individual experiences at their employment airport;
• Each trial was only carried out three time, but at least five trials are needed for quantitative statistical significant results.
Nevertheless the number of trials was regarded to be good for a qualitative investigation of trends. For an enhanced validity of the measured values considerably more simulation trials under various conditions must be performed.
Isdefe Status: Approved Page 43/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
9.1 PROCEDURE OVERVIEW The EVS concept developed in the frame of the OPTIMAL project focuses on the use of weather penetrating sensor technology and the presentation of the image to the pilot on a head-down display.
The recently released final rule (2004) of the FAA for Enhanced Flight Vision Systems (EFVS) clearly acknowledges the operational benefits of such a technology but the use is restricted to head-up displays and U.S. aircraft operating within national airspace.
The All Weather Operations Steering Group (AWOSG) of the JAA has proposed some amendments towards an international standard acceptable by the ICAO but also with the restriction to head-up display technology.
MDA or DA
FAF
≥200ft above threshold
EVS Transition Height
Vertical path provided by EVS
Visual segment flownwithout relying on EVS
Figure 5 EVS concept of operations
9.2 VALIDATION OBJECTIVES The following validation objectives were defined for the EVS procedure:
1. Assess whether the EVS head-down procedure is operational in terms of Precision and Mental Workload of the pilots
Table 8 shows the EVS exercises that were performed in order to meet the above mentioned objectives.
9.3 EXERCISE SUMMARY Objective 1 – Zurich RTS feasibility assessment D7.3.4-2 “Results of Zurich EVS Simulations” (Ref. 30) summarizes the results of two simulation trials carried out for the scenario Zürich, RWY28: one with an ILS precision approach and one with a VOR/DME Non Precision Approach.
Figure 6 shows the results of the second trial in terms of the pilot workload and the lateral / vertical deviation for EVS HDD and EVS HUD.
Isdefe Status: Approved Page 44/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Isdefe Status: Approved Page 45/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
10.1 PROCEDURE OVERVIEW Within OPTIMAL, specific rotorcraft procedures have been studied taking into account steep glide slope procedures and curved/segmented approaches. The procedures developed have been tailored in order to allow simultaneous non interference (SNI) IFR flights of rotorcraft with the aim of not affecting aircraft operations.
10.1.1 Steep straight-in final approach procedure The main feature that distinguishes these procedures from “normal” ones used by fixed wing aircraft is the steep glide slope angle of more than 3º. Values up to 10º have been evaluated in simulation experiments, and values of up to 9º have been tested in-flight. The sensing equipment enabling this procedure is GBAS or SBAS. With both systems the ILS-Look alike concept is followed, i.e. the “standard” ILS indications in the cockpit are provided as well as the same or similar obstacle clearance areas are used.
IF FAF
1000 ft min
Figure 7 Rotorcraft steep approach procedure
10.1.2 Curved final approach procedure When flying curved final approach procedures, rotorcraft are approaching the airport from an angle different from the fixed-wing traffic, which are all aligned with a specific landing runway. At some distance from the airport a curved segment aligns the rotorcraft with the FATO approach direction while staying clear of nearby approaching fixed-wing traffic, landing on a nearby runway.
Because of the curved segment in final approach, this procedure is necessarily of RNP-AR type, thus requiring the helicopter navigation system to be eligible for such operations.
Isdefe Status: Approved Page 46/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
10.2 VALIDATION OBJECTIVES The following validation objectives were defined for the R/C IRF approaches:
1. Assess the impact of the R/C IRF approaches on the capacity of a busy large main airport in terms of ATCo´s workload and number of movements;
2. Assess the flyability (pilot’s workload flight path accuracy), performance (interference with other fixed-wing and/or rotary-wing traffic) and operational aspects (pilot´s and ATCo´s acceptance) of the R/C IRF approaches for a busy large main airport;
3. Assess the environmental impact of R/C IRF approaches (non-SNI and SNI) designed for the Toulouse airport (noise nuisance);
4. Assess the flyability (flight path accuracy), operational aspects (pilot’s acceptance) and performance of the SBAS/GBAS avionics system of steep vertically guided R/C IRF approaches designed for the Toulouse airport;
5. Assess the impact of an IFR rotorcraft SNI approach procedure on the capacity of a single runway system in terms of number of movements;
6. Assess the operational aspects (ATCo´s workload) of an IFR rotorcraft SNI approach procedure;
7. Assess the flyability (flight path accuracy), operational aspects (pilot’s acceptance) and performance of the experimental SBAS-based FMS system of vertically guided R/C IRF approaches designed for the Bremen airport with an EC135;
8. Assess the flyability (flight path accuracy) and operational aspects (pilot’s acceptance) of vertically guided R/C IRF approaches designed for the Donauwörth helipad with an EC145;
Table 9 Overview of rotorcraft IFR Validation exercises
10.3 EXERCISE SUMMARY Objective 1&2 – Schiphol RTS capacity and feasibility assessment D7.3.3-1 “NLR Rotorcraft ATC Integrated Simulations Experimental Results” (Ref. 31) describes the results of the real-time evaluations whereby NLR’s fixed-base helicopter simulator HPS (Helicopter Pilot Station) and later Eurocopter’s SPHERE helicopter simulator were coupled to NLR’s tower research simulator NARSIM, with the aim of performing integrated tests of new steep IFR rotorcraft procedures.
Isdefe Status: Approved Page 47/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Subject of investigation was the acceptability by both ATC and helicopter pilots alike of a helicopter Approach Procedure with Vertical guidance ‘APV’, set up as a Simultaneous Non-Interfering ‘SNI’ procedure, to be flown together with operations of fixed-wing aircraft onto/from the same airport. This SNI procedure has been tested within a simulated busy large main airport environment, for which the Amsterdam airport visual database was used. The glide slope of the APV procedure was set at quite a steep value, viz. 7.5º.
Three novel pilot guidance display concepts, viz. the so-called ‘RNAV-ILS’, ‘ILS-one’ and ‘ILS-squared’ display, were also evaluated in terms of accuracy and flyability.
Three pilots and 3 ATC-controllers participated in the exercise, which took a total of 3 days. Four scenarios were tested, viz. 1) daylight baseline (ILS), 2) daylight SNI, 3) night time SNI, and 4) daylight SNI with missed approaches.
The simulations are summarized in D6.3 (Ref. 6), where also an analysis of the benefit assessment (ATC work load and number of movements) results is given.
Objective 3 – Toulouse environmental impact assessment D7.1.2-2 “Noise Footprint Predictions for Eurocopter EC155” (Ref. 32) presents the predicted noise footprints for the EUROCOPTER EC155 demonstrator performing the IFR approach procedures.
It was shown that the acoustic footprint predictions of the six approach profiles correspond to the expected directivity patterns of the EC155 helicopter. The figures highlight the fact that rotorcraft noise is highly directional and approaches result in noise footprints that are not symmetrical along the flight track. Based on limited measurements, the prediction method used was able to clearly show the effect of changing the flight track, airspeed, descent angle, bank angle, or altitude.
Objective 4 – Toulouse Flight Trial D7.4.3-1 ”Toulouse EC155 SNI approach flight test report” (Ref. 33) presents the results of the EC155 operational flights tests performed carried out in Toulouse airport. These trials assessed the feasibility and the interest of steep vertically guided IFR approaches for joining an airport with commercial traffic.
Eight approach procedures were designed by using ICAO PANS-OP material for SBAS LPV approaches. For each procedure, four different control strategies were assessed: automatic, with the support of a 4-axis AFCS, with the support of a 3-axis AFCS, and manually but still with the basic AFCS stabilisation. Each procedure was tested under SBAS and GBAS guidance
Objective 5&6 – Bremen RTS capacity and feasibility assessment D7.3.3-2 “Results of Bremen R/C SNI ATC Simulation” (Ref. 34), presents the results of the Bremen Airport capacity- and workload-oriented real time simulations on the Radar Simulator ATMOS and the Helicopter-Cockpit Simulator for the IFR rotorcraft SNI approach procedure on a single runway system. Two active controllers from airport Bremen (EDDW, single RWY) supported the simulation and acted as approach controllers in interchanging roles, as 'pickup' and as 'feeder'.
A high traffic approach scenario (fixed wing only) has been chosen as a reference scenario. Up to 8 rotorcraft movements an hour have been added in the various simulation runs, either as additional movements via the SNI-routes or as replacement of fixed wing traffic on the standard IFR approach using the ILS.
Isdefe Status: Approved Page 48/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
The capacity analysis is summarized and analysed in D6.3 (Ref. 6).
Objective 7 – Bremen Flight Trial D7.4.3-2 “Bremen EC135 steep and curved approach flight test report” (Ref. 35) describes the results of the flight trials that have been carried out in Bremen with DLR’s research helicopter FHS, an EC 135. A curved approach procedure with 4D capabilities has been developed in WP2.4 for Bremen airport taking into account the idea of simultaneous non-interfering rotorcraft IFR operations. The functions developed for the FMS allow flying a time referenced curved approach with an RTA given at the Missed Approach Point which has been defined as the end of the curve.
The main objectives of the flight tests were to verify the flyability and pilot acceptance of the curved approach and to assess the 4D capability of the experimental FMS functions. SBAS (EGNOS) has been used as primary input to the navigation system. 35 approaches to Bremen under various weather (wind) conditions have been carried out. The curved approaches were flown with two different Guidance Concepts: a tunnel display (tunnel dimensions 80m x 60m) and a Bug-PFD-guidance display. All approaches have been flown manually without any SAS assistance or autopilot assistance.
In the first 27 approaches, required times of arrival (RTAs) have been given for the MAPt to verify the 4D capability of the FMS.
Objective 8 – Donauwörth Flight Trial D7.4.3-3 “Donauwoerth EC145 steep and curved approach flight test report” (Ref. 36), presents the results of their flight tests performed on ECDs airfield in Donauwoerth during two test campaigns. These tests were aimed at the evaluation of the curved and steep approaches under SBAS guidance developed within WP2.4, using an EC145 demonstrator helicopter.
The test flights of the first campaign were flown manually, with only basic stabilisation support. The trials of the second campaign were executed with the support of a 4-axis automatic flight control system (AFCS). The flight trials were conducted in Visual Meteorological Conditions (VMC) and the wind situation was calm.
The profile of the curved approach was derived from the procedure developed by DLR for the corresponding approach of their EC135 to the airport of Bremen. The steep approach was derived from the FATO32y (3°-9° slope) approach performed by ECF on the airport of Toulouse The approach procedures were stored in the helicopter and with the aid of the EGNOS position data a comparison between the planned and the actual flight path was performed. The deviation between these two has been indicated to the crew by the aid of a tunnel symbology.
10.4 CONCLUSIONS Objective 1&2 – Schiphol RTS capacity and feasibility assessment The results of the IFR-SNI real time simulations indicated the following:
The IFR-SNI approach procedures could increase the ATCo’s workload, especially the physical and the temporal demands were higher than for the baseline procedure. Every new procedure will always lead to higher workloads, until the ATCo’s have learned to handle the new procedure, after which a more fundamentally correct assessment of workload can be made.
Isdefe Status: Approved Page 49/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
The airport’s capacity, in terms of number of movements, clearly increased with the SNI procedure in operation, by about 11% compared to the baseline situation. Operational. The pilot workload was somewhat higher for the SNI procedure than for the baseline procedure, but this is to be expected for any new procedure that involves novel features. In general the SNI procedure was well accepted by the pilots, but the missed approach was at best neutrally accepted or not accepted (rejected). However, the ATCos tended to reject the SNI procedure, depending upon visibility conditions, and alterations should be made. Their major comments concerned the poor non-interfering performance of the procedure (see next paragraph).
Performance. The SNI procedure proved to be not truly Non-Interfering, in that the approach path converged on the ILS approach path towards the airport. Also departing traffic on some departure routes had to be delayed because of possible altitude conflicts with the 3000 ft initial approach altitude.
Flyability. Of the three (lateral) guidance displays, the one with the lowest rated usefulness was the RNAV-ILS guidance display. Pilots did not agree unanimously on which was the best one, but two out of three pilots nominated the ILS-squared display as the best. It also required the lowest workload and had the best (lateral) performance, certainly with regard to the lateral navigational accuracy on final or when passing the Final Roll Out Point, especially in moderate crosswind.
Objective 3 – Toulouse environmental impact assessment It concluded that the IFR SNI approach procedures reduce the noise contours comparing to the baseline scenario5; the 9° glide slope approaches are the best. A 3°-to-9° approach was shown to narrow the contours during the 3° segment, but the noise contour reduction obtained was not as much as the 9° approach.
Objective 4 – Toulouse Flight Trial The main conclusions from the Toulouse flight trials are the following:
• Steep slope (up to 9°) rotorcraft-specific IFR approaches can be flown with good precision both in the lateral and vertical plane thanks to SBAS or GBAS guidance;
• Key feature for low pilot workload is the AFCS (Automatic Flight Control System) airspeed hold mode (IAS) which for steep approaches must be operative at low airspeed to keep an acceptable descent rate (≈800 ft/min) in the final segment. A low minimum IFR speed is also required;
• Although a 4-axis AFCS is always preferable and allows fully coupled approaches, manual control of the vertical axis by collective inputs is relatively easy and consequently, a 3-axis AFCS can also be used;
• SBAS and GBAS are suitable guidance means for rotorcraft-specific IFR approach procedures to airport heliports, in particular in obstacle rich and (or) noise sensitive environments;
• The integration of rotorcraft-specific IFR procedures in a medium airport terminal airspace does not seem to raise major concerns. Simultaneous Non Interfering (SNI) rotorcraft/aircraft operations seem also possible by an appropriate design of the procedures, adapted ATC tools and training of traffic controllers.
5 It must be noted, however, that the prediction of such a large footprint (lateral extent of approximately 6500 m) was outside the validated boundaries of the methodology, which was based on measurements on the centreline and at 150 m to the side. The results must therefore be interpreted carefully, and can only be used in the frame of a comparative study.
Isdefe Status: Approved Page 50/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Objective 5&6 – Bremen RTS capacity and feasibility assessment The following main results have been obtained from the real time simulations:
• Eight additional R/C IFR movements per hour via SNI even in high traffic load are manageable without impacting fixed wing traffic – a throughput of up to 45 arrivals an hour have been achieved;
• There is a decrease in traffic throughput if R/C have to use ILS straight-in approaches together with fixed wing traffic;
• The approach controllers developed a good understanding of the SNI principle;
• The controllers developed the following task sharing for SNI operations:
- Fixed Wing Traffic was controlled using the standard Pickup + Feeder concept;
- The additional R/C traffic on the SNI routes only were controlled by Pickup down to the transfer to TWR;
• Missed approaches of SNI R/C did not add extra problems for Approach Controller. They handled them in a rather efficient manner as missed approaches of fixed wing traffic.
Objective 7 – Bremen Flight Trial The EC135 steep and curved approach flight tests in Bremen showed the following results:
With respect to the Flight Technical Error (FTE), the results obtained with the tunnel display are better than those obtained with the bugs guidance concept. With the tunnel guidance concept, pilot stayed in almost 100% of the flight time from the IF down to the MAPt within the tunnel. Using the bugs display, pilots deviated in up to 15% of the flight trials more than 40 meters from the nominal flight path.
Pilots clearly expressed their preference for the tunnel display. They reported about an important lower workload compared to the bugs display. With the tunnel display, this rather complex procedure, that includes steep and curved segments in addition to speed reductions during the curve, is flyable without further automation. The tunnel itself provided sufficient situation awareness.
Furthermore, in terms of flyability, it was shown that 4D Guidance resulted in an accuracy of ±5 seconds.
It was concluded that:
• The develop curved approach procedure is flyable
• With the tunnel display this rather complex procedure is flyable without further automation and with a sufficient accuracy and an acceptable level of workload.
• The tunnel itself provided sufficient situation awareness.
• With additional speed guidance information, the procedure can be flown with a very good 4D accuracy (less than 5 seconds).
Objective 8 – Donauwörth Flight Trial The conclusions from the Flight Trials at Donauwörth are:
• The evaluated approaches can be flown safely on the EC145, thanks to the support of the 4-axis AFCS. Moreover both procedures have been designed in a way that they can also be flown manually in case of loss of the autopilot.
• The automatic approaches showed higher accuracy.
Isdefe Status: Approved Page 51/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
• The steep approach (both the full 9° slope and the dual 3°/9°slope) is accepted by test pilots as flyable and is a procedure which can be executed without imposing additional workload to the crew as long as the approach speed is kept in the appropriate range.
• The SBAS proved itself to provide adequate position data for the execution of curved- and steep approaches for helicopter IFR approaches.
• The tunnel symbology is a valuable method to present the desired flight path and the deviation to the crew. A deviation can be depicted intuitively so that adequate countermeasures can be initiated by the pilot. During the automatic flight the tunnel provides a useful means to monitor the approach.
Isdefe Status: Approved Page 52/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
11.1 OVERVIEW ATC Safety Net functions are intended to provide a level of protection in the event that human or system errors result in a prediction in a near future of loss or infringement of required standard separation either with other aircraft, terrain or dangerous activities or wake turbulence areas. Safety Nets functions are typically performed by the following applications:
• Short Term Conflict Alert (STCA)
• Minimum Safe Altitude Warning (MSAW)
• Area Proximity Warning (APW)
• Wake Turbulence Encounter Advisory (WTEA)
OPTIMAL Development focussed on STCA and MSAW including APM. Those functionalities raise particular issues in high-density areas such as approach areas, or in mountainous or hazardous regions.
Current ATC Monitoring Aids typically encompass the following:
• Route Adherence Monitoring (RAM),
• Cleared Level Adherence Monitoring (CLAM),
• Approach Path Monitoring (APM).
These monitoring aids are intended to alert controllers to situations where the current performance or behaviour of an aircraft differs from ATC clearances or the ground system view of the flight intent, and which have the potential to jeopardize safety.
The development made in OPTIMAL enabled to improve the performance and accuracy of these functions by taking advantage of Aircraft Derived Data (ADD).
11.2 VALIDATION OBJECTIVES The following validation objective was defined:
1. to improve the performance and accuracy of Safety Nets and Monitoring Aids in approach areas, and to adapt them in order to support new approach procedures.
Table 10 Overview of ATC Tools Validation exercises
11.3 EXERCISE SUMMARY The results of the ATC Safety Nets simulation made on the OPTIMAL_GD (Ground Development) system (Ref. 37) are summarized in D6.3 (Ref. 6). The simulation was more specifically aimed to:
• Decrease Safety Nets False Alarm Rate (FAR) using multi-hypothesis processing, making use of Aircraft Derived Data (ADD) to increase prediction accuracy. Main focus
Isdefe Status: Approved Page 53/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
was given to Short Term Conflict Alert (STCA) and Minimum Safe Altitude Warning (MSAW);
• Improve the performance and accuracy of Monitoring Aids by taking advantage of air-ground data exchange. Main focus was given to Approach Path Monitoring (APM);
• Increase the safety by preventing too low separation between aircraft in heavy traffic situation by the implementation of a new processing Wake Turbulence Conflict Advisory (WTCA);
• Decrease environmental disturbances by preventing open-up of throttle for wake turbulence avoidance thanks to the WTCA
11.4 CONCLUSIONS OPTIMAL has allowed enhancing Ground Based Safety Nets with implementation of multi-hypothesis algorithms which fit the concern of evolutionary air traffic either in horizontal or in vertical level. Moreover, the use of Aircraft Derived Data by Ground Based Safety Nets allows to follow accurately a given set of manoeuvre and to enable more realistic trajectories predictions. The specific processing implemented to cope with the parallel runways will allow to perform SOIR (Simultaneous Operations on Parallel or Near-Parallel Instrument Runways) nevertheless it will depend on the update rate of system tracks provided by SDPS.
Besides, some trials with live data are necessary to confirm the results obtained in simulation. Moreover a statistical approach using real data for Ground Based Safety Nets evaluation will be plus.
Isdefe Status: Approved Page 54/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
12.1 CONCLUSIONS WITH REGARD TO PROJECT OBJECTIVES From the analysis of the results it can be concluded that all the project objectives are met. The advanced procedures provide the expected benefits in terms of capacity and/or environmental impact and/or safety and the procedures are in general feasible:
CDA The conducted simulations and flight trials demonstrated clearly the feasibility of the ACDA procedures and the environmental benefits brought by ACDA. The calculated decrease in maximum throughput was still within future operating standards. The possible implementation of ACDA in a busy ATC environment and the flyability of future ACDA with high accuracy RTA capability was also demonstrated. However, several points need further studies.
GNSS-based procedures The GBAS flight trials demonstrated the flyability of the GBAS procedure and the very good performance of the GBAS system paving the way for future Cat II/III operations. It confirmed several operational benefits of GBAS such as smoother signal for guidance and pilots, reduced workload for controllers and the coverage of multiple runways with only one ground station
The LPV SBAS flight trials demonstrated the good flyability and performance of the SBAS procedure. The operational benefits are especially important for small and difficult airports (as San Sebastian airport used in OPTMAL) facilitating the operations, enhancing safety and decreasing the workload of both pilots and controllers in comparison with non-precision approaches; Introducing SBAS at San Sebastian airport was demonstrated to be economically beneficial. LPV SBAS could be also a back-up for medium and large airports.
Flight trials have demonstrated the feasibility of an ABAS solution to fly LPV approaches and to meet APV 1 criteria.
RNP AR approach procedures The studies demonstrated the benefits of the concept of hybrid RNP-xLS procedures and confirmed the benefits of RNP AR procedures such as improved accessibility in obstacle rich environment, lower minima and environmental benefits. Simulations and flight trials assessing the hybrid RNP-xLS procedures have shown the flyability, pilot acceptance, and performance, although some recommendations for further development and implementation were made regarding need of adapted HMI and training for ATC and airborne side, and need of standardization.
Displaced Threshold operations Simulations have shown that a significant increase of arrival traffic throughput at congested airports can be obtained, without a significant increase in ATCo workload. It was also demonstrated that advanced planning systems are beneficial for DT operations.
Isdefe Status: Approved Page 55/55 This investigation has been carried out under a contract awarded by the European Commission, contract number AIP3-CT-2004-502880
Enhanced Vision System Simulations have shown the operational feasibility of the EVS Head Down Display concept.
Rotorcraft specific IFR Approaches The many simulations and flight trials demonstrated the flyablilty, the benefits and the integration in ATM of the rotorcraft specific procedures studied (steep & curved procedures using GBAS or SBAS guidance and independent Rotorcraft and Aircraft traffic flows: SNI). These rotorcraft specific procedures are key enabler for improving rotorcraft integration at airports as they reduce the noise impact at the airport, increase the airport’s capacity (passenger throughput) and improve safety thanks to vertical guidance.
12.2 RECOMMENDATIONS As can be deduced from the conclusions of each procedure, the maturity levels of the procedures (in terms of the development life cycle phase) are not the same and many of the procedures require further improvement and testing before they can be industrialized and implemented, see also Figure 9. For each procedure the recommendations concerning further development are captured in D8.3 “Final OPTIMAL recommendations” (Ref. 38).
Figure 9 Global maturity level of the OPTIMAL procedures
12.3 LESSONS LEARNT FROM THE VALIDATION APPROACH OPTIMAL was one of the first EC-sponsored projects that applied a methodological approach for planning the validation activities. The approach was based on the E-OCVM, even though E-OCVM did not exist at beginning of project. Application of this approach resulted in a more structured project planning, homogeneous validation efforts across the project and coherency in the objectives and indicators during the different validation exercises. Also, some important lessons were learned:
• In extensive projects, like OPTIMAL, the validation exercises have a high risk of delay, which may delay the “Validation Result Analysis” and the “Elaboration of Validation Conclusions” The project planning should be able to accommodate for delays and the validation management should closely operate with the overall project management.
• The definition of Low Level Objectives and Metrics comes early in project, when, in general, the exercise managers are not ready yet to think in such a detail. Therefore, extra attention is required to agree upon these important first steps of the validation process.
