This paper presents a framework to characterize flight behaviors - common trajectory patterns observable in ADS-B data - and apply these characterizations to two safety-relevant applications: anomaly detection and behavior interaction analysis. By capturing the natural statistical variation in normal aircraft and helicopter operations, the framework enables systematic identification of anomalous trajectories that deviate from nominal behavior, which may reflect operational errors or emergent hazards. The framework also assesses spatial and temporal overlap between behaviors to identify cases where aircraft must rely on tactical, rather than procedural, separation which may elevate the associated collision risk. Flight behavior characterization of arrival, departure, and helicopter trajectories in the terminal airspaces of DCA, JFK, BOS, and SFO show that this approach supports safety analysis by detecting anomalous trajectories and uncovering interactions between flight behaviors in complex airspaces. Results identified anomalies and multiple behavior interactions which may have elevated collision risk. The observed actual navigation performance of RNAV and RNP behaviors were found to be significantly more accurate than the required navigation performance of their corresponding procedures.

Accurate estimation of aircraft takeoff weight (TOW) and landing weight (LW) is critical for assessing fuel consumption, emissions, noise impacts, and other analyses, yet these parameters are typically unavailable in surveillance data such as Automatic Dependent Surveillance-Broadcast (ADS-B). This study presents a method for estimating aircraft takeoff and landing weights using stabilized airspeed segments from ADS-B surveillance data. The approach is derived by relating lift, weight, and airspeed during stabilized flight phases. The method outlined is validated using one year of operations at Seattle-Tacoma International Airport, analyzing over 10,000 flights across three narrow-body aircraft types: B737-800, B737-900, and A320. Weight estimated from ADS-B airspeed profiles was matched to weight records provided by an airline, achieving mean absolute errors of 5.0-7.4% of maximum takeoff weight (MTOW) for departures and 6.0-7.0% of MTOW for arrivals. The method exhibits minimal systematic bias, with absolute distribution mean errors below 0.4% MTOW in magnitude. The demonstrated accuracy enables applications such as fleet-wide fuel consumption modeling, emissions inventories, and aircraft noise impact assessments, providing a valuable tool for data-driven modeling of aviation operations using existing surveillance infrastructure.

NeuralFoil is an open-source Python-based tool for rapid aerodynamics analysis of airfoils, similar in purpose to XFoil. Speedups ranging from 8x to 1,000x over XFoil are demonstrated, after controlling for equivalent accuracy. NeuralFoil computes both global and local quantities (lift, drag, velocity distribution, etc.) over a broad input space, including: an 18-dimensional space of airfoil shapes, possibly including control deflections; a 360 degree range of angles of attack; Reynolds numbers from 10^2 to 10^10; subsonic flows up to the transonic drag rise; and with varying turbulence parameters. Results match those of XFoil closely: the mean relative error of drag is 0.37 on simple cases, and remains as low as 2.0 post-stall and transitional cases. NeuralFoil facilitates gradient-based design optimization, due to its C^∞-continuous solutions, automatic-differentiation-compatibility, and bounded computational cost without non-convergence issues. NeuralFoil is a hybrid of physics-informed machine learning techniques and analytical models. Here, physics information includes symmetries that are structurally embedded into the model architecture, feature engineering using domain knowledge, and guaranteed extrapolation to known limit cases. This work also introduces a new approach for surrogate model uncertainty quantification that enables robust design optimization. This work discusses the methodology and performance of NeuralFoil with several case studies, including a practical airfoil design optimization study including both aerodynamic and non-aerodynamic constraints. Here, NeuralFoil optimization is able to produce airfoils nearly identical in performance and shape to expert-designed airfoils within seconds; these computationally-optimized airfoils provide a useful starting point for further expert refinement.

Aircraft weight estimation is a common problem facing researchers working with aircraft surveillance data. Although knowledge of an aircraft’s weight and thrust is required for many types of analyses, such as those evaluating aircraft acoustic noise, fuel burn, and emissions, these parameters are typically not available from surveillance sources. Instead, researchers generally only have access to basic aircraft states: lateral position, groundspeed, and altitude. Therefore, methods for estimating the weight of aircraft from these basic states become necessary in cases where aircraft performance is a key component of the analysis. This paper introduces two weight estimation models: one for the estimation of aircraft takeoff weight from departure data, and another for the estimation of aircraft landing weight from arrival data. The models are mathematically simple but grounded in knowledge of aircraft certification, airline operations, and aircraft flight management system logic. The landing weight estimation model proposed is shown to have a mean absolute error equivalent to 2.66% of maximum takeoff weight and a standard deviation of 3.35% of maximum takeoff weight when validated using onboard data recordings from 240 Airbus A320 flights. Similarly, the proposed takeoff weight estimation model is shown to have a mean absolute error of 2.83% of the maximum takeoff weight and a standard deviation of 3.55% of the maximum takeoff weight when applied to the same validation dataset.

This paper presents a review of published final investigation reports of accidents, serious incidents, and incidents in transport category aircraft worldwide from 2000 to 2024. A total of 872 publicly available investigation final reports were analyzed from 51 national investigative agencies recognized by the International Civil Aviation Organization. Failures of 11 different aircraft systems were identified and studied to determine flightcrew awareness of system failure as well as appropriateness of flightcrew response. The results indicate that flightcrew responded appropriately in 84% of failure cases included in the reports. When evaluated by type of system failure the appropriate response rates were: Powerplant 88%; Landing Gear 84%; Air Conditioning and Pressurization 84%; Instruments and Navigation 73%; Flight Controls 85%; Electrical System 92%; Hydraulic 89%; Fuel 64%; Autoflight 54%; Structural 95%; and Communication 100%. An increasingly prevalent initial cue for flightcrew awareness of failure was found to be Alerting and Annunciation, including centralized Crew Alerting Systems in the more modern Generation 3 and Generation 4 aircraft. A comparison is presented between the results of this study and a previous analysis of 1990s final reports carried out by the Royal Netherlands Aerospace Center.

A broad range of advanced air mobility (AAM) aircraft are currently in development, each with varying community noise footprints and energy consumption depending on the specifics of their departure and arrival flight trajectories, which must be understood for effective airspace integration. This work presents a framework for analyzing AAM trajectory design, focusing on key performance characteristics, including community noise impact, energy consumption, and flight duration. The framework can be applied to diverse AAM vehicle types, as demonstrated in this work on a blown-flap short takeoff and landing vehicle, a tilt-rotor vertical takeoff and landing vehicle, and a lift-plus-cruise vertical takeoff and landing vehicle. Results of comparing various takeoff procedures for each vehicle show tradeoffs between community noise, energy consumption, and flight duration, highlighting the importance of strategic trajectory design.

The implementation of performance-based navigation instrument flight procedures at major U.S. airports has enabled aircraft to follow precise routes during departure and arrival operations. While these procedures offer increased efficiency and predictability in flight management, they have the side effect of concentrating aircraft noise over specific neighborhoods along procedure routes. At Boston Logan Airport, performance-based navigation procedures led to increased aviation noise complaints due to the higher flight track concentration. To mitigate this effect, new low-noise procedures were developed and implemented at Boston Logan. The procedure changes include a new overwater approach procedure to runway 33L and modifications to the departure procedures from runways 15R and 22L/R. This paper evaluates changes in noise levels measured by ground noise monitors and the fuel burn impacts due to changes in path lengths introduced by the new procedures. All implemented procedures resulted in reduced overflight noise at a highly impacted area on the approach path to runway 33L and the departure path to runways 15R and 22L/R, resulting in a reduction ranging between 2.9 and 18.3 dB [Formula: see text]. All published procedures were observed to have a reduced average distance flown between 0.1 and 7.3 nautical miles, which resulted in a fuel-saving co-benefit.

Air transportation supports economic growth and global connectivity but imposes localized environmental costs, particularly through aircraft noise. We estimate the causal effect of aviation noise on housing prices using quasi-experimental variation from the Federal Aviation Administration's rollout of performance-based navigation (PBN) procedures and runway reconfigurations at three major U.S. airports. Combining high-resolution flight trajectory data with geocoded housing transactions, we apply a difference-in-differences hedonic framework to identify changes in exposure unanticipated by residents. A one-decibel increase in annual day-night average sound level reduces house prices by 0.6 to 1.0 percent. Among alternative noise metrics, average exposure explains property value impacts most strongly. Willingness to pay for quieter conditions varies systematically with income and race, indicating that aircraft noise externalities have meaningful distributional consequences. Our results highlight the need to incorporate localized environmental costs into aviation and urban land-use policy. Institutional subscribers to the NBER working paper series, and residents of developing countries may download this paper without additional charge at www.nber.org.

Launch activity is increasing in the U.S. and this increases the frequency of times each year that airspace needs to be integrated, or shared among space and air traffic operators. In order to protect air traffic and the public from possible launch failures or malfunctions, restricted airspace called Special Use Airspace is used for launches. An analysis of Special Use Airspaces shows that typically, as the size and activation period of Special Use Airspaces increases, the number of rerouted aircraft increases, which increases the overall air traffic rerouting cost. However, shorter Special Use Airspaces, which may limit rerouting costs, may also limit the ability for launch providers to avoid launch scrubs due to unforeseen launch contingencies. Thus, from the perspective of airspace allocation, there is a tradeoff between the cost of rerouting aircraft and the potential cost of delaying a launch. The results from analyzing this tradeoff show that there may be opportunities to reduce the impact of space launches on air traffic in the future by changing the timing and length of Special Use Airspaces for future space launch operations, and that these opportunities may result from equitably balancing the cost of rerouting aircraft with potential launch provider delay costs.

The implementation of Performance-Based Navigation instrument flight procedures at major US airports has enabled aircraft to follow highly precise routes during departure and arrival operations. While these procedures have offered increased efficiency and predictability, they have had the side-effect of concentrating aircraft noise over specific neighborhoods along procedure routes. At Boston Logan Airport, the implementation of Performance-Based Navigation procedures led to an increase in aviation noise complaints received by the airport due to the higher flight track concentration. To mitigate this effect, new low-noise procedures were developed and implemented at Boston Logan through a technical collaboration involving the Federal Aviation Administration and Massport. The procedure changes include a new overwater approach procedure to runway 33L and modifications to the departure procedures from runways 15R and 22L/R. This paper evaluates changes in aircraft noise levels measured by ground noise monitors and the fuel burn impacts due to changes in path lengths introduced by the new procedures. It was found that all of the implemented procedures resulted in a reduction in overflight noise at a highly impacted area on the approach path to runway 33L and the departure path to runways 15R and 22L/R, resulting in a reduction ranging between 2.9 and 18.3 dB L-A,L-MAX. All published procedures were observed to have a reduced average distance flown between 0.1 and 7.3 nautical miles, which resulted in a fuel savings co-benefit.

Low-thrust, end-burning solid rocket motors have applications as propulsion systems for a class of small, transonic, uncrewed aerial vehicles. This paper provides new experimental measurements for characterizing small, low-thrust, end-burning motors. Four static fires measured the effects of motor chamber pressure and propellant oxamide content on exhaust plume radiant intensity, which could be important for vehicle visibility and tracking. Exhaust plume radiant intensity was found to be sensitive to a change in oxamide content and relatively insensitive to a change in chamber pressure for these motors. Thrust, chamber pressure, and burn rate were also measured for these motors, and a model for the minimum burn pressure of oxamide-doped propellants was improved.

This work introduces a noise abatement procedure for reducing aircraft community noise during departures based on the control of climb profiles via procedural level-offs. The proposed procedure consists of enforcing an altitude restriction along a departure path such that aircraft maintain level flight when overflying strategically selected regions. During this level segment, thrust demand is lower than during climbing flight, which results in lower engine noise. However, this effect must be balanced with the lower aircraft altitude in the level segment, which may reduce the distance between aircraft and observers. Thus, a systematic analysis methodology is needed to design an effective noise abatement procedure based on this technique, which has been developed and is presented in this paper. Modeling results show potential undertrack peak A-weighted noise level reductions of 2–4 decibels for both narrowbody and widebody aircraft in the level-off area depending on the level-off altitude and an associated increase of 1.5–6 decibels in the region where the climb is resumed. An example application of this procedure is demonstrated at Boston Logan Airport, with cumulative changes in noise impacts being assessed for one full day of operations. In this example application, fuel burn penalties are estimated at 37 pounds for a representative narrowbody operation and 142 pounds for a representative widebody operation.

This study investigated the correlation between aircraft noise exposure and noise complaints at two major airports: Boston Logan International Airport (KBOS) and Seattle Tacoma International Airport (KSEA), both for the year 2019. A novel method is used to correlate complaints and noise on a daily basis. We reveal that for both airports, complaints are filed between 40 and 80 daily Day-Night Level (DNL) thresholds. The median threshold for complaints is between 55-60 daily DNL for KSEA, and between 45-60 daily DNL for KBOS. Complainants were also grouped into three categories based on the noise levels at which they filed complaints - low sensitivity (<55 daily DNL), medium sensitivity (55-65 daily DNL), and high sensitivity (>65 daily DNL). Near KSEA, high sensitivity groups were primarily located north of the airport, and along the water west of the airport. Near KBOS, high sensitivity groups are further inland in clusters, west and southwest of the airport. For KBOS we also find significant overlap of high and low sensitivity groups as some complainants can receive, and file complaints at, both 45 daily DNL and 60 daily DNL due to daily variations in noise patterns. We find the daily variation in median noise threshold for complaints in KBOS comes from different operating procedures at KBOS.

This paper proposes an end-to-end differentiable model for infrared radiant emission for low-altitude exhaust plumes. Considering plume radiant emission during the design phase is important for ensuring vehicle design constraints and objectives can be met while accounting for the coupling of plume radiant emission with other aspects of vehicle design. The model is suitable for computational frameworks using automatic differentiation or gradient-based optimizers-such as CasADi and AeroSandbox-which enable direct optimization of solid rocket-powered vehicle design with constraints on plume radiant emission. It consists of six submodels of different coupled physical phenomena: chamber thermodynamic equilibrium, motor internal ballistics, isentropic nozzle flow, plume flow field, afterburning kinetics, and radiative transfer. The combined model shows reasonable agreement for several different rocket-powered vehicles. The use of the model is demonstrated in an example case study for optimizing a low-thrust, transonic, rocket-powered aircraft concept.

Advanced Air Mobility (AAM) is an evolving field of research seeking to transform sustainable air transportation in urban and sub-urban environments amid increasing urbanization and traffic congestion. The evolution of AAM requires efficient management of congested airspace and the accommodation of diverse vehicles with distinct performance capabilities. A broad range of AAM aircraft are in development which will have different community noise footprints and energy use depending on the details of the departure and arrival flight trajectories which must be understood for airspace integration. This work presents a framework for analyzing AAM trajectory design, focusing on key performance characteristics including community noise impact, energy consumption, and flight duration. The framework can be applied to diverse AAM vehicle types, as demonstrated in this work on a Blown-Flap Short Takeoff and Landing vehicle, a Tilt-Rotor Vertical Takeoff and Landing vehicle, and a Lift Plus Cruise Vertical Takeoff and Landing vehicle. Results of comparing various takeoff procedures for each vehicle show trade-offs between community noise, energy consumption, and flight duration, highlighting the importance of strategic trajectory design.

A hydrogen-based air transportation network could play a key role in decarbonizing aviation, which currently accounts for about 3% of anthropogenic climate change. Hydrogen conversion for long-haul (as opposed to short-haul) flights would concentrate infrastructure change to large airports and maximize climate impact. In this paper, the key components of such a network are defined and its energy demand is estimated. A design study for an example liquid-hydrogen-fueled long-haul transport aircraft is performed to estimate fuel demand for the network. The energy conversion chain is quantitatively modeled, from on-site electrolysis to liquefaction, storage, distribution, fueling, and flight. Implementation feasibility of necessary components is discussed and technological challenges are identified. The study concludes that liquid-hydrogen long-haul networks are feasible from a flight physics and technological perspective, but worldwide hydrogen production capacity would need to be greatly increased. The amount of clean electricity needed to power the proposed long-haul network in this study is 2.91 TWh per day which is 36% of current global green energy production or 30% of current global nuclear energy production.