This SAE Aerospace Information Report (AIR) developed by a broad cross section of personnel from the aviation industry and government agencies is offered to provide state-of-the-art information for the use of individuals and organizations designing new or upgraded turboshaft engine test facilities. Purpose a. To provide guidelines for the design of state-of-the-art ground-level enclosed test facilities for turboshaft engine testing. b. To address the major test cell engine load absorption device physical@ aerodynamic and acoustic characteristics which can influence operation@ performance@ accuracy and stability of an engine under test. c. To consider acoustic and environmental effects and methods to control them.