Loss of the ILS Localizer Antenna Signal

TASK 34-36-00-810-846-A
Loss of the ILS Localizer Antenna Signal

1. Possible Causes

MMR-1 [40RT1]
MMR-2 [40RT2]
ANTENNA-LOCALIZER 1/2 [3RT]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 34-36-00-740-003	BITE Test of the MMR
ASM 343601
AMM 34-36-11-000-001	Removal of the Localizer Antenna
AMM 34-36-11-400-001	Installation of the Localizer Antenna
AMM 34-36-31-000-001	Removal of the ILS Receiver
AMM 34-36-31-400-001	Installation of the ILS Receiver

3. Fault Confirmation
Subtask 34-36-00-740-108-A

A. Test
Do the BITE test of the MMR1 AMM 34-36-00-740-003.

4. Fault Isolation
Subtask 34-36-00-810-106-A

A. If the test of the MMR1 only gives the maintenance message
LOCALIZER ANTENNA (3RT)/COAX CABLE/MMR1(40RT1):

swap the MMR-1 [40RT1] and the MMR-2 [40RT2] AMM 34-36-31-000-001 and AMM 34-36-31-400-001
do the BITE test of the MMR1 AMM 34-36-00-740-003.

(1) If the test of the MMR1 gives the maintenance message
LOCALIZER ANTENNA (3RT)/COAX CABLE/MMR1(40RT1):

remove the MMR1
remove the localizer antenna 1/2 AMM 34-36-11-000-001
make sure that there is continuity on the ANTENNA-LOCALIZER 1/2 [3RT] ASM 343601
replace the coaxial cable if necessary
make sure that there is discontinuity between the core and the shield of the coaxial cable
repair if necessary
install the MMR1
install the localizer antenna 1/2 (3RT) AMM 34-36-11-400-001.

(2) If the test of the MMR1 does not give the maintenance message
LOCALIZER ANTENNA (3RT)/COAX CABLE/MMR1(40RT1):

replace the MMR that you installed on side 2.

Subtask 34-36-00-810-107-A

B. If the test of the MMR2 only gives the maintenance message LOCALIZER ANTENNA (3RT)/COAX CABLE/MMR2(40RT2):

swap the MMR-1 [40RT1] and the MMR-2 [40RT2] AMM 34-36-31-000-001 and AMM 34-36-31-400-001
do the BITE test of the MMR2 AMM 34-36-00-740-003.

(1) If the test of the MMR2 gives the maintenance message LOCALIZER ANTENNA (3RT)/COAX CABLE/MMR2(40RT2):

remove the MMR2
remove the localizer antenna 1/2 AMM 34-36-11-000-001
make sure that there is continuity on the ANTENNA-LOCALIZER 1/2 [3RT] ASM 343601
replace the coaxial cable if necessary
make sure that there is discontinuity between the core and the shield of the coaxial cable
repair if necessary
install the MMR2
install the localizer antenna 1/2 (3RT) AMM 34-36-11-400-001.

(2) If the test of the MMR2 does not give the maintenance message
LOCALIZER ANTENNA (3RT)/COAX CABLE/MMR2(40RT2):

replace the MMR that you installed on side 1.

Subtask 34-36-00-810-108-A

C. If the test of the MMR1 gives the maintenance message
LOCALIZER ANTENNA (3RT)/COAX CABLE/MMR1(40RT1) and if the test of the MMR2 gives the maintenance message
LOCALIZER ANTENNA (3RT)/COAX CABLE/MMR2(40RT2):

replace the ANTENNA-LOCALIZER 1/2 [3RT] AMM 34-36-11-000-001 and AMM 34-36-11-400-001.

Subtask 34-36-00-740-109-A

D. Do the test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:33:01 UTC