Developing an Aircraft Weight Database for AEDT

Transcription

1 Recommended Allocation: $250,000 ACRP Staff Comments This problem statement was also submitted last year. TRB AV030 supported the research; however, it was not recommended by the review panel, which noted the FAA is addressing this issue through other research means. TRB Aviation Committee Comments ENVIRONMENTAL IMPACTS OF AVIATION: Limited support. Reviewers were mixed on this problem statement. Several felt this would support developing an aircraft weight takeoff database and improving defaults in AEDT. Others felt this was a topic that AEE is working on for the next version of AEDT. Review Panel Recommendation and Comments Recommended. The consensus of the review panel was that anything to make the AEDT model more accurate would be beneficial. Yet there was also cautious recognition that ACRP research resulting in suggestions for model improvements cannot be directly implemented with respect to changes to the model. Isn't this something FAA/Volpe should do? Where would users get the data? And if there is a database, who would maintain it? AOC Disposition This problem statement received an average rating of 2.2 points out of a possible 5 points among voting AOC members. There was no discussion. No funds were allocated.

2 ACRP Problem Statement Problem Statement Title: Background: Average domestic aircraft load factors have steadily increased from a low of 60.7% in 1990 to a record 84.5% in Legacy and Low Cost Carriers (LCC) have reduced equipment capacity leading to higher load factors using narrow-body aircraft on domestic and some international routes formally served by wide-body aircraft. These narrow-body aircraft were not 1) anticipated to carry load factors over 80% on a consistent basis or 2) fly transcontinental routes. These two factors lead to heavier aircraft on departure than are assumed in the FAA s Aviation Environmental Design Tool (AEDT). AEDT Version 2b is based on Legacy carrier s break-even load factor percentages below 70%; this was revolutionized by LCC flying narrow body aircraft with higher load factors on longer routes. Aircraft inputs into AEDT are based in part on aircraft size, destination, fuel burn, and assuming smaller/narrow body aircraft fly shorter routes. Assumptions about shorter routes include an aircraft that has enough fuel for a route no longer than 500 nautical miles with little cargo and 65% load factor. The last year that United States domestic load factors were 65% was in 1995; since then, aircraft load factors have been well above that, even after the events of 2001 and the recession of This leads to aircraft that execute departure climbs at angles that more closely match longer stage lengths than aircraft assumed to have a lower load factor, less fuel, and less cargo. AEDT aircraft noise modeling tools are used in part to output DNL/CNEL contours used by airports for long-term land use planning, noise abatement efforts, and residential sound insulation program eligibility. Given the steady increase in load factors over the past 21 years and change from the Legacy model to LCC, there is a gap between how airlines operate and how these operations are modeled by practitioners. This gap can lead to inaccurate analysis and a prediction of aircraft noise contours that are smaller than what is actually generated by aircraft operations. Technical Notes: In AEDT, stage length is defined as a range of trip distances. The idea behind using stage length is that the longer the trip, the heavier the assumed average takeoff weight due to increased fuel requirements. Historically, it has been easier to obtain trip length data than average aircraft weight data, so stage length has been used as a surrogate for aircraft takeoff weight. However, given that aircraft weight directly affects the departure profile, it is important to obtain average takeoff weight if it is feasible. The reason is that a shorthaul flight could carry full load of passengers and ferry extra fuel, and the practitioner would unknowingly under predict noise by using stage length. 1 United States Department of Transportation, Bureau of Transportation Statistics, T-100 Segment Data, March 2015 BridgeNet International P a g e 1

3 Profile weight is the weight of the aircraft during the operation. Aircraft fuel burn is not accounted for, so the weight remains constant over the entire operation. o If procedural profiles are used, departure profile weight influences the altitude that can be attained in a given amount of ground distance, thus affecting the noise produced by the airplane. o For approach procedural profiles, weight influences the thrust required to maintain a descent profile, thus affecting the noise produced by the airplane. o For fixed-point profiles, altitude and thrust are pre-computed and the weight parameter is used only for reference. Objective: Develop an aircraft weight database that can be incorporated into AEDT instead of relying on stage length. Determine how often this database should be updated and the mechanism to get it updated in future updates to AEDT. Proposed Tasks: The research plan should include appropriate interim deliverables that include at a minimum: and A working paper describing the results from a review of existing aircraft weight databases, including the T-100 Segment Data from the Bureau of Transportation Statistics. An interim report that includes: Survey airports with radar to determine delta between actual aircraft climb profile and AEDT climb profile for specific aircraft, extrapolating this to DNL/CNEL noise contour output analysis. Survey the aircraft weight data for airports representative of small, medium, and large hubs. The research plan should describe sources for aircraft weight data, the proposed airports to be included in the analysis (and the rationale for their consideration), and criteria to evaluate results; A plan for coordinating with the AEDT Support/Development Team to ensure research results are compatible with the AEDT aircraft noise model; A plan for peer review (including SAE A-21 Committee on Aircraft Noise) of model improvements; and A prioritized list of potential AEDT improvements and the rationale for their prioritization (e.g., precision, cost, data requirements, ease of implementation). The research plan should build in appropriate checkpoints with the ACRP panel, including at a minimum: (1) a kick-off teleconference to be held within 1 month of Notice to Proceed; (1) one web-enabled meeting to discuss the results of the working paper; (1) one face-to-face meeting to discuss the results of the interim report; and (4) other web-enabled meetings or teleconferences tied to the panel review and ACRP approval. BridgeNet International P a g e 2

4 The final deliverables will include: (1) A technical report documenting the entire research effort, including the research methodology, results, and a prioritized list of additional related research needs; (2) Detailed documentation of model improvements (e.g., process map, equations, data, validation and verification) to improve the noise prediction accuracy of AEDT; and (3) A supplement to the AEDT User Guide to help practitioners incorporate updates. The supplement should describe input data, the modeling method, and generation and interpretation of results. Estimated Funding: The estimated funding for this project is $250,000. This accounts for the above tasked items. Estimated Research Duration: The duration of this project is estimated to be 16 months. It is assumed the majority of the schedule will be in the initial tasks of creating draft research plan and data analysis. Related Research: The team preparing the Problem Statement examined existing data sources, including for related research. This search found information regarding load factors, but not a relationship between load factors and assumed aircraft weight related to stage lengths. ACRP has funded programs related to AEDT, including improving arrival and departure profiles, helicopter noise modeling guidance, modeling of ground surfaces, taxi noise, and emissions reporting. 2 Process Used to Develop Problem Statement: The process used to formulate this Problem Statement included discussion between the airport and consultant staff. This discussion was prompted by a previous need by the airport to adjust the stage lengths for its Noise Exposure Map update, including a request to the FAA for amended stage-lengths. The process also included review of historic radar data showing aircraft climb profiles for certain heavily-traveled routes were, on average, lower than the INM noise departure profiles. 2 ACRP Projects 2-55, 2-54, 2-44, 2-52, 2-27 and 2-45 BridgeNet International P a g e 3

5 Person(s) Submitting the Problem Statement: Bert Ganoung Noise Abatement Office Manager San Francisco International Airport Aircraft Noise Abatement Office E: P: In Conjunction With: Justin W. Cook Vice President BridgeNet International E: P: BridgeNet International P a g e 4