A test apparatus and method of electrical testing especially useful for verifying normal performance of essential functions in an aircraft atmospheric pressure responsive auxiliary altimeter under either of flight line or maintenance shop conditions. The tester provides electrical power and control signals needed to energize each of three functions in the considered altimeter instrument including instrument face illumination, altimeter stiction-limiting mechanical vibration generation, aircraft output signal generating potentiometer function and enables electrical current and voltage monitoring relating to the instrument functions being tested. Replacement of individual test instruments and other informal test apparatus with a convenient and probably more electrical accident-free integrated tester is contemplated.
