Failure of the Oil Pressure Indication on Engine 1

TASK 79-00-00-810-807-A
Failure of the Oil Pressure Indication on Engine 1

1. Possible Causes

lubrication unit
XMTR-OIL PRESS [4003EN]
SDAC-1 [1WV1]
SDAC-2 [1WV2]

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 31-55-34-000-001	Removal of the SDAC
AMM 31-55-34-400-001	Installation of the SDAC
AMM 71-00-00-000-040	Removal of the Power Plant
AMM 71-00-00-000-042	Removal of the Power Plant
AMM 71-00-00-400-040	Installation of the Power Plant
AMM 71-00-00-400-042	Installation of the Power Plant
AMM 71-00-00-710-006	Minimum Idle Check
AMM 72-31-00-290-001	Inspection of the High Pressure Compressor Rotor Assembly
AMM 72-31-00-290-002	Inspection of the High Pressure Compressor Rotor Assembly
AMM 72-56-00-000-001	Removal of the Flame Arrestor and Flange Assembly
AMM 72-56-00-000-003	Removal of the Flame Arrestor and of the Flange Assembly
AMM 72-56-00-400-001	Installation of the Flame Arrestor and Flange Assembly
AMM 72-56-00-400-003	Installation of the Flame Arrestor and of the Flange Assembly
AMM 79-00-00-210-002	Walk-around Inspection
AMM 79-00-00-210-004	Walk-around Inspection
AMM 79-00-00-281-002	Check of the Electrical Master Chip Detector (EMCD) for Particles
AMM 79-00-00-281-003	Check of FWD Sump, AFT Sump, AGB, and TGB Scavenge Screens
AMM 79-21-10-000-001	Removal of the Lubrication Unit
AMM 79-21-10-000-004	Removal of the Lubrication Unit
AMM 79-21-10-210-002	Check of the Lubrication Unit Magnetic Plugs and Scavenge Screens
AMM 79-21-10-400-001	Installation of the Lubrication Unit
AMM 79-21-10-400-004	Installation of the Lubrication Unit
AMM 79-33-15-000-040	Removal of the Oil Pressure Transmitter
AMM 79-33-15-000-041	Removal of the Oil Pressure Transmitter
AMM 79-33-15-400-040	Installation of the Oil Pressure Transmitter
AMM 79-33-15-400-041	Installation of the Oil Pressure Transmitter
AMM 79-35-00-040-042	Replacement of the Main Oil Supply Filter and Check of the Electrical Chip Detector Visual Indicator (pop-out)
ASM 793601

3. Fault Confirmation
Subtask 79-00-00-710-062-A ** ON A/C NOT FOR ALL

A. Test
(1) Not applicable.

4. Fault Isolation
Subtask 79-00-00-810-056-A ** ON A/C NOT FOR ALL

A. Do a visual inspection of the engine to make sure that there are no leaks AMM 79-00-00-210-004.
(1) If nothing is found:

do a check of the lubrication unit magnetic plugs and screens AMM 79-21-10-210-002.

(a) If you find magnetic particles:

follow the related instructions per AMM 79-21-10-210-002 and NDT Manual (section CHIP ANALYSIS).

(2) If nothing is found:

do a check for cracks/leaks at oil tank, lubrication, external oil supply and scavenge lines.

(a) If there is sign of heavy oil discharge in the center vent tube:

replace the engine AMM 71-00-00-000-040 and AMM 71-00-00-400-040.

(b) If nothing is found:

do a check of the flame arrestor for clogging.

1 If confirmed:

clean or replace it AMM 72-56-00-000-003 and AMM 72-56-00-400-003.

(3) If nothing is found:

remove the TBG/AGB drain plug and do a check for abnormal oil quantity.

(a) If there is more than one quart:

do a check for oil scavenge line blockage or replace the lubrication unit AMM 79-21-10-000-001 and AMM 79-21-10-400-001.

(4) If nothing is found:

do a borescope inspection of the high pressure compressor stage 1 and 2 to see if they are wet with oil AMM 72-31-00-290-001,
do an inspection of the fan blades and booster stage 1 at 6 o'clock to see if they are wet with oil,
do an inspection of the frame struts and aft side of stage 4 low pressure blades to see if they are wet with oil.

(a) If there is oil:

replace the engine AMM 71-00-00-000-040 and AMM 71-00-00-400-040.

Subtask 79-00-00-810-057-A ** ON A/C NOT FOR ALL

B. If nothing is found:

Replace the XMTR-OIL PRESS [4003EN] AMM 79-33-15-000-040 and AMM 79-33-15-400-040.

(1) If the fault continues:

do a check of the electrical wiring between the ENG1 OIL PRESS XMTR (4003EN), the SDAC1 and the SDAC2 ASM 793601.

(2) If the fault continues:

replace the SDAC-1 [1WV1] AMM 31-55-34-000-001 and AMM 31-55-34-400-001

(3) If the fault continues:

replace the SDAC-2 [1WV2] AMM 31-55-34-000-001 and AMM 31-55-34-400-001

Subtask 79-00-00-810-056-B ** ON A/C NOT FOR ALL

C. Do a visual inspection of the engine to make sure that there are no leaks AMM 79-00-00-210-002 .
(1) Do a check of the electric master magnetic chip detector visual indicator AMM 79-35-00-040-042 and the magnetic chip detector AMM 79-00-00-281-002 and the scavenge screen plugs AMM 79-00-00-281-003.
(a) If you find magnetic particles:

follow the related instructions per AMM 79-00-00-281-002 and NDT Manual (section CHIP ANALYSIS).

(2) If nothing is found:

do a check for cracks/leaks at oil tank, lubrication, external oil supply and scavenge lines.

(a) If there is sign of heavy oil discharge in the center vent tube:

replace the engine AMM 71-00-00-000-042 and AMM 71-00-00-400-042.

(b) If nothing is found:

do a check of the flame arrestor for clogging.

1 If confirmed:

clean or replace it AMM 72-56-00-000-001 and AMM 72-56-00-400-001.

(3) If nothing is found:

remove the TBG/AGB drain plug and do a check for abnormal oil quantity.

(a) If there is more than one quart:

do a check for oil scavenge line blockage or replace the lubrication unit AMM 79-21-10-000-004 and AMM 79-21-10-400-004.

(4) If nothing is found:

do a borescope inspection of the high pressure compressor stage 1 and 2 to see if they are wet with oil AMM 72-31-00-290-002,
do an inspection of the fan blades and booster stage 1 at 6 o'clock to see if they are wet with oil,
do an inspection of the frame struts and aft side of stage 4 low pressure blades to see if they are wet with oil.

(a) If there is oil:

replace the engine AMM 71-00-00-000-042 and AMM 71-00-00-400-042.

Subtask 79-00-00-810-057-B ** ON A/C NOT FOR ALL

D. If nothing is found:

Replace the XMTR-OIL PRESS [4003EN] AMM 79-33-15-000-041 and AMM 79-33-15-400-041.

(1) If the fault continues:

do a check of the electrical wiring between the ENG1 OIL PRESS XMTR (4003EN), the SDAC1 and the SDAC2 ASM 793601.

(2) If the fault continues:

replace the SDAC-1 [1WV1] AMM 31-55-34-000-001 and AMM 31-55-34-400-001

(3) If the fault continues:

replace the SDAC-2 [1WV2] AMM 31-55-34-000-001 and AMM 31-55-34-400-001

Subtask 79-00-00-710-063-A ** ON A/C NOT FOR ALL

E. Do a minimum idle check AMM 71-00-00-710-006.

[Rev.8 from Aug 2018] 2026.04.04 04:38:21 UTC