Cost/Benefit Tradeoffs Available in Aircraft Noise Technology Applications in the 1980's

The current status of aircraft noise control technology is reviewed to identify those measures that have a reasonable potential for application to aircraft coming into service in the 1980's. Noise reduction achievable when these noise control measures are applied to two transport category airplanes, a business jet, and a small propeller-driven twin is determined. Costs and performance penalties are determined for each noise control option. Benefits are measured by reductions in FAR 36 certification noise levels and in reductions in EPNL contour areas. The study shows that current, late 1970's, noise control practices permit transport category airplanes to meet the FAR 36 Stage 3 noise limits, yet application of additional noise control measures is not likely to provide additional reduction of the noise levels for these aircraft by more than 3 decibels. New business jet noise levels will be as much as 10 decibels lower than Stage 3 limits for takeoff, and as much as 5 decibels lower on approach, with additional reductions of more than 3 decibels unlikely. Introduction of newly designed, geared reciprocating engines would provide reductions of 10 or more decibels for high performance single and twin-engined, propeller-driven small airplanes, relative to existing practice. (Author)