Systems analysis of community noise impacts of advanced flight procedures for conventional and hybrid electric aircraft

Abstract

Recent changes to aircraft approach and departure procedures enabled by more precise navigation technologies have created noise concentration problems for communities beneath flight tracks. There may be opportunities to reduce community noise impacts under these concentrated flight tracks through advanced operational approach and departure procedures and advanced aircraft technologies. A modeling method to assess their impacts must consider the contributions of aircraft engine and airframe noise sources as they vary with the position, thrust, velocity, and configuration of the aircraft during the flight procedure. The objective is to develop an analysis method to design, model, and assess the community noise reduction possibilities of advanced operational flight procedures performed by conventional aircraft and advanced procedures enabled by future aircraft concepts.

An integrated analysis framework is developed that combines flight dynamics and noise source models to determine the community noise impacts of aircraft performing advanced operational approach and departure procedures. Aircraft noise due to the airframe and engine is modeled using an aircraft source noise module as each noise component varies throughout the flight procedure and requires internal engine performance states, the flight profile, and aircraft geometry. An aircraft performance module is used to obtain engine internal performance states and aircraft flight performance given the aircraft technology level. A force-balance-kinematics flight profile generation module converts the flight procedure definition into altitude, position, velocity, configuration, and thrust profiles given flight performance on a segment-by-segment basis.

The system generates single-event surface noise grids that are combined with population census data to estimate population noise exposure for a given aircraft technology level and procedure. The framework was demonstrated for both advanced approach and departure procedures and advanced aircraft technologies. The advanced procedure concepts include modified speed and thrust departures as well as continuous descent, steep, and delayed deceleration approaches for conventional aircraft. The ability to model advanced aircraft technologies was demonstrated in the evaluation of using windmilling drag by hybrid electric aircraft on approach to allow the performance of steep and delayed deceleration approaches for noise reduction beyond the performance capability of standard gas-turbine aircraft.