Piper Navajo PA-31 Service Manual page 893

PIPER NAVAJO SERVICE MANUAL
SECTION XII
ELECTRONICS
12-1. INTRODUCTION. This section of the manual is divided into two parts. The first part contains
information necessary to perform operational checks of the Emergency Locator Transmitter (ELT) and
Pilot's Remote Switch used with the ELT. Included are the appropriate removal and installation
instructions to facilitate battery replacement. The second part consists of schematics and harnesses of the
various configurations of avionics equipment installations. (Refer to Aerofiche grid 4A6.)
12-2. EMERGENCY LOCATOR TRANSMITTER (GARRETT MFG. LTD.).
12-3. DESCRIPTION. The electrical power for the ELT is totally supplied by its own self-contained battery.
However, aircraft power is required to shut off the transmitter with the remote switch. For portable use, the
ELT can be easily removed from its mounting in the aircraft. FAA regulations require that the battery be
replaced: 1) on or before the expiration date on the unit; 2) if the transmitter has been used in an emergency
situation; 3) if the accumulated test time exceeds one hour or 4) if the unit has been inadvertently activated for
an undetermined time period.
12-4. BATTERY REMOVAL AND INSTALLATION. (2 year, magnesium battery, refer to Figure
12-1.) The ELT is located underneath the dorsal fin between sta. 304.75 and sta. 317.00.
a. Remove the access panel on the dorsal fin between sta. 296.00 and sta. 317.75 by removing the
screws.
b. Set the ON/ARM/OFF switch on the transmitter to the OFF position.
c. Disconnect the antenna coax from the transmitter.
d. Disconnect the harness to the pilot's remote switch from the transmitter. (On Serial Nos.
31-7300979 & up.)
e. Remove the rear mounting bracket by pulling the plastic knob out. Remove the transmitter from
the airplane.
f.
Remove the two long or four short screws securing the transmitter plain end cap. Remove the
plain end cap.
g.
Disconnect the battery connector from the board terminals.
h. Withdraw the battery pack from the transmitter case.
i.
Before installing the new battery pack, check the replacement date printed on the battery.
Transfer this date onto the outside of the ELT. Make an entry in the aircraft logbook of the new battery
replacement date.
j. Slide the new battery pack, plain end first, into transmitter. It may be necessary to rotate the
battery slightly to get it seated properly in the transmitter case and to achieve correct orientation of the
battery connector.
k. Connect the battery connector to board terminals.
1. Insure O-ring is fitted in plain end cap and correctly seated.
NOTE
Red ELTs have no O-ring; replace end cap using fresh RTV
silicone rubber compound.
m. Refit end cap and secure with the screws previously removed.
Revised: 9/24/81
ELECTRONICS
5A11