Piper Navajo PA-31 Service Manual page 896

PIPER NAVAJO SERVICE MANUAL
a. Remove the access panel on the dorsal fin between sta. 296.00 and sta. 317.75 by removing the
screws.
b. Tune the aircraft communications receiver to 121.5 MHz and switch the receiver ON; deactivate
the squelch, and turn the receiver volume up until a slight background noise is heard.
NOTE
If the aircraft is not fitted with a communications receiver, request
that the tower listen for your test.
c. On the transmitter, set the ON/ARM/OFF switch to the ON position. Keep the switch in this
position for only a few seconds; then set to the OFF position. Return to the ARM position.
NOTE
The test transmission should have been picked up by the aircraft
communications receiver and/or control tower. During cold
weather, there may be a slight delay before transmission occurs.
d. A transmitter which is functioning properly should emit a characteristic downward swept tone.
e. When the test is completed, ascertain the transmitter ON/ARM/OFF switch is in the ARM
position.
f. Place the access panel on the dorsal fin between Sta. 296.00 and sta. 317.00 and secure with the
appropriate screws.
WARNING
Whenever the unit is checked by moving the transmitter
ON/ARM/OFF switch from the ARM to the ON position, it must
then be moved to the OFF position before reverting to the ARM
position again.
CAUTION
Under normal conditions, the transmitter switch must be set to
arm.
NOTE
Inspect the external whip antenna for any damage. Avoid bending
the whip. Any sharply bent or linked whip should be replaced.
Antenna damage may cause structural failure of whip inflight.
Reissued: 10/12/79
ELECTRONICS
5A14