Mooney M20TN, Service And Maintenance Manual

Page: 391 / 1169

MOONEY AVIATION COMPANY, INC.
M20TN SERVICE & MAINTENANCE MANUAL
Date
2006
Rev Date
Page 15
ELT are checked and a set of error codes generated if a
problem is found. The error codes are displayed by a
series of pulses of the ELT LED, remote LED and alert
buzzer. See “Transmitter Test” for more details and a
description of the error codes.
-- WARNING --
Do not allow test duration to exceed 5 seconds.
Any time the ELT is activated it is transmitting a
121.5 MHz distress signal. If the unit operates for
approximately 50 seconds, a “live” 406 MHz dis-
tress signal is transmitted and is considered val-
id by the satellite system. Any time that the ELT
is cycled from “ARM” to “ON” and then back to
“ARM,” a 406 MHz signal is transmitted, however
it is specially coded as a “self test” signal that is
ignored by the COSPAS--SARSAT satellites.
Transmitter Test
Always perform the tests within the first 5 minutes of the
hour. Notify any nearby control tower of your intentions,
in accordance with AC 43.13.1B, Section 12--22, Note
3. If outside the U.S., always follow all local or national
regulations for testing of ELTs.
Self Test
Tune a receiver (usually the aircraft radio) to 121.5
MHz. Turn the ELT aircraft panel switch “ON” for about
1 second, then back to the “ARM” position. The receiv-
er should voice about 3 audio sweeps.
At turn--off (back to the “ARM” state) the panel LED and
buzzer should present 1 pulse. If more are displayed,
determine the problem from the list below.
Codes displayed with the associated conditions are as
follows:
1 Flash -- Indicates that the system is operational
and that no error conditions were found.
3 Flashes -- Bad load detect. Detects open or short
condition on the antenna output or cable. These prob-
lems can probably be fixed by the installer.
Check that the RF cable is connected and in good
condition. Perform continuity check of center conductor
and shield. Check for a shorted cable.
Check for intermittent connection in the RF cable.
If this error code persists, there may be a problem
with the antenna installation. This can be checked with
a VSWR meter. Check the antenna for opens, shorts,
resistive ground plane connection.
4 Flashes -- Low power detected. Occurs if output
power is below about 33 dBm (2 watts) for the 406 sig-
nal or 17 dBm (50 mW) for the 121.5 MHz output. Also
indicate that 406 signal is off frequency. For this error
code the ELT must be sent back for repair or replace-
ment.
5 Flashes -- Indicates that the ELT has not been pro-
grammed. Does not indicate erroneous or corrupted
programmed data.
6 Flashes -- Indicates that the G--switch loop be-
tween pins 5 and 12 at the D--sub connector is not
installed. ELT will not activate during a crash.
Check that the harness D--sub jumper is installed
by verifying less than 1 ohm of resistance between pins
5 and 12.
7 Flashes -- Indicates that the ELT battery has too
much accumulated operation time (>1 hr.). Battery may
still power ELT; however, it must be replaced to meet
FAA specifications. May also indicate damage to the
battery circuit.
Remote Switch LED always ON (Steady) -- Indi-
cates wiring error or frayed wires shorting out pins on
back of Remote Switch. To correct, verify wiring and in-
tegrity of all crimp or solder connections on harness.
Self--Test Schedule
Artex recommends that the ELT be tested every 1--2
months. Follow steps outlined above. Note: the self--
test time is accumulated in a register on the battery
pack. The register records activation time in 30 second
increments so all activations will count as at least 30
seconds, even if actual time is much less. Total allow-
able time is 60 minutes as determined by FAR 91.207
and RTCA DO--204. After this time has been accumu-
lated, a 7 flash error will be presented after the self--
test. The battery must be replaced at this point for the
ELT to remain in compliance.
Once all tests have been satisfactorily completed and
all harness connections have been verified to be cor-
rect, the connectors at the remote cockpit switch and
the ELT should be sealed to prevent moisture from get-
ting into the wire entry holes.
Seal using an electronics grade (neutral cure) non--
slumping RTV such as GE Silicone RTV162, Dow
Corning 748RTV or Silastic 1080RTV. These are com-
monly available at pet stores which sell aquariums.
Apply RTV to the rear of the 9--pin connector remote
switch (Artex P/N 151--5009), forcing the sealant into
wire holes and around exposed wire ends.
Disassemble the harness D--sub connector and cover
exposed wire ends and all connectors pins with RTV.
Coat all exposed metal, taking care to keep away from
the thumb screws. Reassemble after sealing.
BATTERY REPLACEMENT -- ARTEX ME--406
Remove ELT
Remove the ELT from its mounting tray. Inspect the
mounting hardware. Ensure the hardware is free of
cracks or other obvious damage Battery removal.
NOTE:
The battery pack contains static sensitive parts,
take ESD precautions before handling.
Remove the (8) securing screws from the battery-side
cover (Figure 39--19). Battery pack is identified by the
embossed text: “BATTERY ACCESS ON THIS SIDE”.
Carefully lift the battery cover (battery pack) away from
39--12--02
AUGUST 2010