Testing of aircraft equipment

A test stand is provided with multiple flanges for connection to individual pieces of auxiliary aircraft equipment of the driving or driven variety, outside of the aircraft, preferably right before installation therein. The test stand includes additionally a gear train with shafts for connection to the equipment to be tested as well as to a test drive motor, a blower for cooling air, and a hydraulic pump or compressor. The shaft to the test drive motor is used as pick up for speed and torque during the test. One of the shafts is disconnectible from the train by a clutch and is connected to a fly-wheel and/or brake. Rotary power generating equipment such as a gas turbine, hydraulic motor and/or air turbine are tested by using either the fly wheel and/or brake as a load or by controlling an electric test drive motor as generator.