Key Results

The quantitative analysis of EXE01 “Gate to Gate” concentrated on 12 RAD measures that were managed dynamically, involving DFS, DSNA, ENAV and skyguide. More than 8400 flights took advantage of the improved routes made available, resulting in an estimated reduction of more than 2 800 tons of CO2 emissions (an average of about 350 kg per flight *) coming from a fuel-burn reduction of about 890 tons (an average of more than 100 kg per flight *).

(*) Note: this overall average should not be read too literally, since the savings are very different, for different relaxed RAD restrictions, depending on the involved flights. It has been calculated to give a high level idea of the effect improvements adding up in time and space.

This exercise mainly resulted in prolonged application during several weeks of improvements made possible by the MUAC control center, located centrally in the city-pairs of the consortium members. These improvements were: Pre-tactical relaxation of a RAD constraint; Several DCT direct routings allowed tactically; Proposal (tactically to the crews) of the highest possible flight level.

The MUAC improvements could be combined with the optimized descents into CDG, enabled by DSNA.

The measured reductions of CO2 emissions systematically correspond to 2-5% of the emissions generated in the concerned segments of flight (typically lasting 15 to 45 minutes). This unit amount must be multiplied by the high number of flights to which the improvements were offered.

NM was in charge of the coordination with different stakeholders of these last trials, run during second half of November and first half of December, with an active contribution of MUAC to prepare the demo flights in their AoRs. These trials, as those run in March, were focused on the possibility to provide benefits to selected consortium flights (e.g. Air France, Lufthansa, Swissair, Novair, Wizzair) whenever possible, without specific treatment but just as result of the coordination between the different stakeholders. The trials took also benefits by other activities running in the same period, namely the dynamic RAD in Spain and France. MUAC provided great contributions to this last set of demo flights, addressing different improvements identified for a number of city pairs.

During the Connecting European Days event, organized in Lyon, France, on June 28, 2022 five flights have been coordinated among ATM and AUs partners to demonstrate the potentiality of the gate to gate approach. The execution of the flights confirmed the full cooperation of the involved actors, ANSPs and military, as well as the majority of the Aircraft Operators operating routes to Lyon. The primary goal of the demonstrating flights was to show the potential ATM improvements in contributing to the reduction of CO2 emission through optimized trajectories. The special treatment asked for the execution of the flights should not be considered as “solution” per se but as opportunity of improvements through standard coordination.

The two parts of the exercise, EXE-02A and EXE-02B, were strongly linked, so the results can be described together.

The availability of a very large dataset of flight data, correlated with the specific conditions of the arrival airports, and correlated with the actual ATC clearances given to the flights made it possible to have very specific and detailed quantitative measurements of the impact of various constraints on arrivals (for illustration: for closed-loop arrivals into ESSA the average excess fuel due to vertical inefficiency is reduced by 24kg; the ratio of vertical inefficiency between best-case and worst-case number of clearances can be more than double).

The works from the exercise were generalized into the definition of a method that can be used for assessing the efficiency/inefficiency related to the operational environment based on FDR data. This method can practically help to get an idea of what kind of operational challenges are causing vertical inefficiencies, in a specific TMA. The method also estimates the "excess CO2 emissions", from increased fuel-burn, that each inefficiency can cause.

EXE-03 has evaluated the benefits of closed-path PBN-to-ILS procedures in a direct comparison between manually-controlled and pilot-assisted aircraft energy management. EXE-03 provides particularly valuable lessons for further widespread deployment of PBN-to-ILS procedures with the goal of maintaining high capacity and utilizing different types of aircraft energy management functions. In the case of EXE-03, the aircraft energy management function LNAS was used.

Flights along the PBN-to-ILS trajectory conducted with LNAS support resulted in significantly more predictable vertical and airspeed profiles, lower average thrust settings, lower use of speed brakes particularly at low altitudes, and overall lower fuel burn from the last 30 NM compared to PBN-to-ILS approaches without a pilot assistance system and compared to approaches using radar vectoring. Optimum flights using LNAS result in a fuel burn of 6.1% lower than the baseline flights

The analysis of airspaces and traffic flows with the help of machine learning (AI) was successful, in that it allows to identify which factors lead to good or less good trajectories, in the specific operational conditions of a TMA: In summary, the solutions that enable more efficient vertical flight profiles include: performing lateral sequencing and separation in a larger airspace, therefore obtaining a better use of the runway resource; and flexible descend windows and raised transfer levels.

Notice that this exercise did not directly calculate an amount of CO2 reduction; it concentrated instead on identifying the conditions that determine the best- and worst-performing flights, to derive priorities in the factors to implement.

The work is first carried out for Frankfurt; The findings will then be used to transfer the approach to the DUS/CGN airspace system.

EXE-05A "PBN-to-ILS VIE"

The full process that culminated with the permanent publication of the procedure has been successfully carried out : Coordination with local communities and governmental bodies at and around Vienna airport as part of the institutionalized “mediation”; Procedure design phase (multiple iterations); Safety Assessment including all stakeholders; Procedure evaluation using full-flight simulators and Live-Trail flights in VMC conditions (multiple Aircraft and FMS type); ATC training; Publication of the procedure in the Austrian AIP with AIRAC November 3rd, 2022.

Implemented PBN-to-ILS on RWY 29 will be usable by all flights into Vienna (depending on traffic situation, only used in off-peak periods at the beginning, but active and available H24)

Benefits assessment by Austro Control / Eurocontrol on the noise exposure / reduction, fuel burn and evaluating CO2 reductions from reduced track miles and improved flight efficiency (using AEDT / IMPACT).

EXE-05B "Airbus DPO/IFO"

This exercise demonstrated the benefits of the DPO and IFO solutions : DPO is an improvement of the accuracy of an aircraft type applying at the entry into service of the aircraft. IFO is an improvement of the accuracy by MSN all along the life of this aircraft. The use of IFO allows maintaining the fuel benefits mainly obtained with DPO along the time. These solutions bring an improvement in the management of the energy in descent: reduction of airbrakes usage; increase of Idle thrust usage; encourage the use of the FMS management mode in descent.

In this exercise, IFO was applied on 362 flights. The estimated benefit per flight being of around 16kg of CO2, the total reduction of CO2 obtained in this exercise is at ~5792kg (~6T). The impact of IFO depends on the age of the aircraft, which are quite recent for the exercise: it could be up to ~50kg of fuel and 160kg of CO2 per descent (estimated).

In addition to the values, the demonstration of the capacity to optimize the descent profile computed by the FMS suggests that additional benefits can be expected by the combination of these functions with ATM solutions as for example: Continuous Descent Operations, Controlled Time of Arrival or by the use of the EPP, taking benefit of a potential improvement in terms of predictability.

EXE-06A "PBN-to-Final at CDG": Advanced evaluation methodologies were devised by DSNA and by AF for the Live Trials carried out for the preparation of "PBN-to-Final" procedures at Paris-CDG. These methodologies allowed to quantify the benefits of the PBN to ILS/RNP procedures both in terms of noise and CO2 emissions. The observed benefits were more or less pronounced for different arrival flows and traffic conditions. The sizes of the samples used for the assessment were smaller than hoped for, and therefore the significance of the quantitative results is limited. However, the PBN-to-Final concept is confirmed as a crucial building block (in the final segment) for achieving an optimized profile along the entire descent.

EXE-06B "Green Descents CDG"

In the timeframe of the project, an opportunistic improvement of the altitudes at some IAF points for Paris-CDG arrivals has evolved into permanently available improved arrival procedures. These could be applied on thousands of flights over several months. A clearly measurable reduction of CO2 from reduced fuel-burn can be detected. This amounts to 300 kg of CO2 saved (average) for each improved flight in the case of wide-body aircraft and 100 kg of CO2 for medium-haul aircraft. For the quantitative assessment on this exercise, Air France used the tools and methodology established in EXE-06A.

EXE-06C "Pilot assistance tools for flight profile optimization"

Following a successful "study phase" on a limited number of pilots, the OptiClimb tool was rolled out to the entire Boeing long-haul fleet of Air France (40~60 departures from CDG every day). The usage of a finely calculated climb profile (still within the acceptable envelope for ATC) results in an average reduction of more than 300 kg of CO2 per departure. The rate of application of this process is very high, resulting in a significative cumulative benefit.

EXE-06E "SEPHER Hydrogen generators"

Two experiments were conducted (in real conditions with an operational ground equipment), with different technology providers of hydrogen technologies, to provide back-up energy to DSNA's Mesnil-Amelot “P+S” radar on the Paris-CDG airport platform, during a period of 4 days (96 hours). The exercise estimated that the carbon footprint from using an electro-hydrogen generator is reduced by more than 85% compared to diesel generator. (Notice that this CO2 reduction is net of the part that might be needed for hydrogen production, since the hydrogen used in the installations used was either "green" or had its CO2 impact compensated for.)

Additional important results of the exercise are the insights gained into the quality of service of such systems, into the supervision process, and some elements of ROI calculation. These are all key aspects to consider in view of a large deployment in very many DSNA sites.

Four out of the five exercises of EXE-06 "French Cluster" were successfully conducted in real operations and for prolonged periods of time (the exception being EXE-06C "Single-engine Taxi-out" whose scope had to be reduced). The exercises systematically spurred close and constructive cooperation between the ANSP and the airlines, which brings fruits beyond the strict scope of the projects. In two cases the outcomes of the activity directly continue into permanent deployment.

The continued collaboration together with the other local sector partners allowed to achieve meaningful progress on some of the main hypotheses and gain some of the envisioned learnings to create and further enrich/validate a draft CONOPS for Sustainable Taxiing operations with TaxiBots at Amsterdam Airport Schiphol. This culminated in the demonstration of operations during a Sustainable Taxiing showcase on airside.

Furthermore, progress on the following concrete aspects could be achieved: progress on the TaxiBot certification of the B737 MAX; An updated design of the TaxiBot, including relevant subsystems; Actual training of stakeholders and improved training materials; Development and realization of a number of infrastructural modifications to allow for TaxiBotting operations to and from the Polderbaan, the investigation of an alternative approach to Sustainable Taxiing at Amsterdam Airport Schiphol with a focus on centralized scale-up to maximize short-term uptake within current operational and procedural boundaries.

These developments all contribute to bringing Sustainable Taxiing operations closer, and lay the groundwork for upcoming trials and possible implementations steps, some of which will take place under the HERON consortium. Furthermore, all these points contribute to the ALBATROSS objective to "progress towards long-term and wide-scale implementation of the operational improvements identified as technically bringing a reduction of CO2 emissions".