Strobe lights - The Anti-Collision Strobe Lights will not switch off

TASK 33-48-00-810-805-A
Strobe lights - The Anti-Collision Strobe Lights will not switch off

1. Possible Causes

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TSM TASK 32-31-00-810-802-A	LGCIU Fault
ASM 323104
ASM 323106
ASM 326202
AMM 33-48-00-710-002	Operational Test of the Anti-Collision/Strobe Lighting
ASM 334801

3. Fault Confirmation
Subtask 33-48-00-865-050-A

A. Make sure that this(these) circuit breaker(s) is(are) closed:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
121VU	HYDRAULIC/LGCIU/SYS2	2GA	Q35
121VU	HYDRAULIC/LGCIU/SYS1/GRND SPLY	52GA	Q34
122VU	LIGHTING/EXT LT/BEACON/UPPER	1LV	U06
122VU	LIGHTING/EXT LT/BEACON/LOWER	5LV	U03
122VU	LIGHTING/WING/STROBE	10LV	V05

Subtask 33-48-00-710-058-A

B. Do the operational test of the Anti-Collision / Strobe Lighting AMM 33-48-00-710-002.

4. Fault Isolation
Subtask 33-48-00-810-056-A

A. If the test confirms the fault when during the test the switch LT-STROBE SW 11LV is in the OFF position:

make sure that on the overhead panel 25VU the switch LT-STROBE SW 11LV is in the OFF position for the next step.
do a check for approximately 115 VAC at the switch LT- STROBE SW 11LV, connector 2A ASM 334801.

(1) If there is approximately 115 VAC:

open, safety and tag this(these) circuit breaker(s):
CB 10LV.
replace the switch LT-STROBE SW 11LV on panel 25VU.
remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
CB 10LV.

(2) If there is no 115 VAC:

open, safety and tag this(these) circuit breaker(s):
CB 10LV.
replace the PWR SPLY-RELAY 12LV on panel 103VU.
remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
CB 10LV.

Subtask 33-48-00-810-057-A

B. If the test confirms the fault only when the switch LT-STROBE SW 11LV is in the AUTO position:

make sure that on the overhead panel 25VU the switch LT-STROBE SW 11LV is in the AUTO position for the next step.

(1) If the fault continues:

open, safety and tag this(these) circuit breaker(s):
CB 2GA
CB 10LV.
do a check and repair as necessary the wiring between:
the LDG SIGNAL-RELAY 13LV connector Z and ground ASM 334801.
remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
CB 2GA
CB 10LV.

(2) If the fault continues:

do a check for approximately 28 VDC at the LDG SIGNAL-RELAY 13LV, connector X ASM 334801.

(a) If there is approximately 28 VDC:

open, safety and tag this(these) circuit breaker(s):
CB 2GA
CB 10LV.
replace the LGD SIGNAL-RELAY 13LV on panel 103VU.
remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):
CB 2GA
CB 10LV.

(b) If there is no 28 VDC:

do the trouble shooting procedure for a fault in the LGCIU-2 5GA2 or the related circuits (Ref. TSM TASK 32-31-00-810-802) ASM 326202 ASM 323104 ASM 323106.

Subtask 33-48-00-710-059-A

C. Do the test as given in the Para. 3.B.

5. Close-up
Subtask 33-48-00-860-054-A

A. Put the aircraft back to its initial configuration.

[Rev.8 from Aug 2018] 2026.04.04 04:32:02 UTC