Downloaded from https://www.everyspec.com ADS-39A-HDBK 19 November 1996 AERONAUTICAL DESIGN STANDARD HANDBOOK SOURCE APPROVAL AND ENGINEERING TEST REQUIREMENTS FOR ALTERNATE SOURCES OF HELICOPTER DRIVE SYSTEM ASSEMBLIES AND COMPONENTS UNITED STATES ARMY AVIATION AND TROOP COMMAND ST. LOUIS, MISSOURI AVIATION RESEARCH AND DEVELOPMENT CENTER DIRECTORATE FOR ENGINEERING