Airworthiness and Flight Characteristics Test (A&FC) of the CH-47D helicopter

An Airworthiness and Flight Characteristics Test of the Boeing Vertol CH-47D helicopter (USA S/N 81-23383) was conducted by the U.S. Army Aviation Engineering Flight Activity. The test was conducted at St. Paul, Minnesota (elevation 704 feet). Edwards Air Force Base (elevation 2302 feet), Bishop (elevation 4120 feet), and Coyote Flats (elevation 9980 feet), California. A total of 148.8 hours (105.4 productive hours) were flown between 25 January and 13 December 1983. Hover, level flight, and autorotational descent performance tests were conducted. Handling qualities tests included static and dynamic stability, maneuvering stability, takeoff and landing characteristics, power management, simulated systems failures, simulated Instrument Meteorological Conditions flight evaluation, and vibration evaluation. Cockpit and subsystem evaluations were also made. The CH-47D exceeded those performance requirements of the Prime Item Development Specification which were evaluated during this test. The Advanced Flight Control System heading select capability and the pressure refueling capability were found to be enhancing characteristics of the aircraft. Three significant shortcomings were found: the poor engine governing system which allows large rotor speed excursions with changes in power setting or airspeed, the high level of cockpit vibrations at and above cruise airspeeds, and an easily excited three-axis airframe oscillation during high power conditions at light gross weight.