ICAO helicopter noise measurement repeatability program : U.S. test report, Bell 206L-1, noise measurement flight test

PDFTech ReportFAA-EE-85-6HelicoptersFlight testsAircraft noiseMeasurementStandardsStandardizationCertificationSound levelTest proceduresWashington (District of Columbia)United States. Federal Aviation Administration. Office of Environment and EnergyNewman, J. StevenRickley, Edward J.Locke, MaryaliceUnited States. Federal Aviation Administration. Office of Environment and EnergyJohn A. Volpe National Transportation Systems Center (U.S.)Operations Research IncorporatedAGR-IMPACTS-EnvironmentNTL-AVIATION-Aviation Energy and EnvironmentVolpe National Transportation Systems Center, Technical Reference CenterThis document reports the findings of the U.S. test team's participation in the Helicopter Noise Measurement Repeatability Program (HNMRP) conducted under the direction of the International Civil Aviation Organization's (ICAO) Committee on Aviation Environmental Problems (CAEP) Working Group II (WG II). The FAA, as the U.S. test team, conducted the HNMRP noise measurement flight test program in concert with a separate measurement team from Canada. The U.S./Canadian flight test was held in August of 1984 at Dulles International Airport near Washington, D.C. The principal objective of this international HNMRP is to refine noise certification testing requirements. Participating nations conducted the test programs on the same type of helicopter, the Bell 206L-1 (or the acoustically equivalent 206L-3), using the same test procedures. Analyses in this document include the investigation of source noise, adjustment based on increases in noise level with advancing blade tip Mach number, the examination of relative source contributions in the helicopter acoustical spectrum, and source directory for both in-flight and static operations. This report contains helicopter noise definition information (useful in environmental impact analyses) for level flyovers at various airspeeds and altitudes, and ICAO takeoff and approach procedures. Data are also shown for a noise abatement operation involving dynamic changes in torque, rate of descent and airspeed. This report also provides information for hover-in-ground effect, flight idle and ground idle static operations. The results reported in this document will be combined with those of other HNMRP participant nations for evaluation by CAEP WG II