With the exception of a few airliner business jets that do not meet the noise limitations of Federal Aviation Regulations Part 36, the business jet fleet is getting quieter. Today, 80 percent of the 25 models of business jets flying in the United States are within the limitations of the present FAR Part 36.
Furthermore, all business jets now in the design phase will be powered by quieter fanjet engines, and all will have sound levels well within the present FAR Part 36 guidelines.
Noise rules in force for the current fleet of small propeller-driven business aircraft apply only to aircraft for which type certification application was made after October 10, 1973. All propeller-driven aircraft operating today applied for type-certification before 1973. However, propeller-driven aircraft operators and engineers were concerned with reducing the noise levels long before any regulations existed. Of the current fleet of propeller-driven aircraft, approximately one third fall below the noise limits that will apply in 1980 and beyond.
This paper looks at the standing of the business aircraft fleet in relation to FAR Part 36 and examines some of the operational and engineering techniques developed by operators and manufacturers in reducing aircraft noise disturbance over airport communities and to the public in general.
The public can be assured that business aircraft are getting quieter. Although much of the past decrease in noise levels can be attributed to operator flying techniques, further progress in noise reduction is ultimately in the hands of aircraft, engine and propeller engineers.