Selection of TEST on the doppler control panel initiates a system self-test providing that the ASE coupler is disengaged. The TRACK/OFF switch on the GVI shall be selected to TRACK and the hover indicators selected to D mode. During the initial portion of the self-test cycle, the KNOTS and TRACK displays should be blank, the DRIFT ANGLE pointer will indicate 0 degrees and the MEM and MAL annunciators will illuminate. After approximately 7 seconds, if the test is successful, the GVI will indicate 188 knots groundspeed, TRACK will read 888, DRIFT ANGLE will read 20 degrees right and the MEM and MAL annunciators will extinguish. The hover indicators will display the following:

a. Vh (horizontal bar) – 2 divisions up.
b. Vd (vertical bar) – 2 division right.
c. Vz (vertical velocity bug) – 2 divisions up.

The resultant displays should remain static for approximately 8 seconds and then the doppler system will automatically revert to normal

If the initial test is unsuccessful, the doppler will perform another self-test. If the second test also fails, the doppler system will revert to normal operation and the MAL annunciator will illuminate. To attempt another self-test turn the doppler mode selector on the control to OFF for 45 seconds. Turn the mode selector to LAND for 2 minutes then initiate a second TEST function.

To minimize heading errors, self-test should not be invoked in flight unless a doppler malfunction is suspected.