Business Jet Approach Noise Abatement Techniques - Flight Test Results

Operational techniques for reducing approach noise from business jet aircraft were evaluated in flight by measuring the noise generated by five such aircraft during modified approaches. Approaches with 4° glide slopes were approximately 4.0 EPNdB quieter than approaches with standard 3° glide slopes. Noise reductions for low-drag 3° approaches varied widely among the airplanes tested; the fleet-weighted reduction was 8.5 EPNdB. Two-segment approaches resulted in noise reductions of 7.0 EPNdB to 8.5 EPNdB 3 nautical miles and 5 nautical miles from touchdown. Pilot workload increased progressively for the 4°, low-drag 3°, and two-segment approach.