Advanced Takeoff Procedures for High-Speed Civil Transport Community Noise Reduction 921939
Advanced takeoff procedures were developed for a Mach 2.62 high-speed civil transport configuration (HSCT) equipped with turbine bypass engines, with the goal of reducing the takeoff noise levels for certification to FAR 36, Stage 3 noise levels. The detailed takeoff and landing module for the Flight Optimizations System (FLOPS) computer program was used to generate takeoff profiles. All takeoff procedures were constrained to meet a FAR takeoff field length of 11,000 feet, as well as the minimum required engine-out climb gradients for each airborne segment. Aircraft noise levels at the FAR 36 certification points were calculated using the Aircraft Noise Prediction Program (ANOPP). The study showed that using advanced takeoff procedures in noise certification could result in a 2.25 dB reduction in the amount of noise suppression required to certify this configuration for Stage 3 noise limits. Advanced procedures also resulted in an 8% reduction in the 100 EPNdB noise footprint area compared to basic FAR 36 takeoff procedures. In addition, improvements in the lift-to drag ratio using high-lift devices were shown to produce 1.81 dB more noise reduction when used in combination with advanced takeoff procedures.