Aircraft Instrument Systems Instrument static system leakage can be detected by observing the rate of change in indication of the a. airspeed indicator after suction has been applied to the static system to cause a prescribed equivalent airspeed to be indicated. b. altimeter after pressure has been applied to the static system to cause a prescribed equivalent altitude to be indicated. c. altimeter after suction has been applied to the static system to cause a prescribed equivalent altitude to be indicated.