NOISE CERTIFICATION OF BELL MODEL 412, 230, AND 206L-4 HELICOPTERS

This paper describes three noise certification test programs and presents results of data analyses leading to noise compliance of five configurations of the Bell Model 412, 230, and 206L-4 series helicopters. In the paper, noise certification standards for helicopters are reviewed. The requirements that determine the extent of the flight testing and the sophistication of the data acquisition and processing systems are reviewed in the appendices. The required systems are described. Insights are given of the numerous activities involved in test planning, the pretest buildup of aircraft and ground based instrumentation, the preparation of the test site, the acquisition of the test data, the post-test data analyses and the determination of compliance. The paper concludes that noise certification of helicopters is a major effort and recommends measures toward successful, efficient certification.