Check for Contamination of the Fuel with Hydraulic Fluid

TASK 49-31-00-200-002-A
Check for Contamination of the Fuel with Hydraulic Fluid

WARNING: MAKE SURE THAT THE FWD AVIONICS ACCESS DOOR 811 IS OPEN WITH A WARNING PLACARD ATTACHED TO IT. THE WARNING NOTICE MUST TELL PERSONS NOT TO CLOSE THE DOOR. THIS PREVENTS ACCIDENTAL PRESSURIZATION OF THE AIRCRAFT.

WARNING: BE CAREFUL NOT TO GET AIRCRAFT FUEL IN YOUR MOUTH OR IN YOUR EYES. IF YOU GET FUEL ON YOUR SKIN OR ON YOUR CLOTHES, FLUSH IT IMMEDIATELY WITH WATER. IF NECESSARY, GET MEDICAL HELP. AIRCRAFT FUEL IS POISONOUS.

WARNING: DO NOT GET YOUR CLOTHES SOAKED WITH FUEL.

WARNING: MAKE SURE THAT YOU HAVE THE CORRECT FIRE FIGHTING EQUIPMENT AVAILABLE.

WARNING: MAKE SURE THE AREA AROUND THE AIRCRAFT IS SAFE BEFORE YOU START THE REFUEL/DEFUEL PROCEDURE. IN THE SAFETY AREA, DO NOT:

SMOKE
MAKE SPARKS OR FIRE
USE ANY EQUIPMENT WHICH IS NOT APPROVED FOR REFUEL/DEFUEL PROCEDURES.

AIRCRAFT FUEL IS FLAMMABLE.

CAUTION: DO NOT TRY TO PULL THE HANDLE OF THE FILLER CAP OUT OF ITS STOP LIMITS.

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE
No specific	1	ACCESS PLATFORM 8M (26 FT) - ADJUSTABLE
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
315AL, 316AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 12-31-28-660-001-A	Cold Weather Maintenance - Fuel
TASK 12-32-28-281-802-A	Sample Fuel for Hydraulic-Oil Contamination Analysis
TASK 24-42-00-861-001-A	Energize the Ground Service Network from the External Power
TASK 24-42-00-862-001-A	De-energize the Ground Service Network Supplied from the External Power
TASK 28-00-00-910-001-A	Fuel Safety Procedures
TASK 29-00-00-864-001-A	Put the Related Hydraulic System in the Depressurized Configuration before Maintenance Action
TASK 49-31-41-000-002-A	Removal of the Pilot Fuel Nozzles and Manifold (APS 3200)
TASK 49-31-41-200-003-A	Inspection / Check of the Pilot Fuel Nozzles and Manifold (APS 3200)
TASK 49-31-41-400-002-A	Installation of the Pilot Fuel Nozzles and Manifold (APS 3200)
TASK 49-31-42-000-003-A	Removal of the Main Fuel Nozzles and Manifold (APS 3200)
TASK 49-31-42-200-005-A	Inspection / Check of the Main Fuel Nozzles and Manifold (APS 3200)
TASK 49-31-42-400-005-A	Installation of the Main Fuel Nozzles and Manifold (APS 3200)
TASK 49-32-11-000-002-A	Removal of the Fuel Control Unit (APS 3200)
TASK 49-32-11-400-002-A	Installation of the Fuel Control Unit (APS 3200)
TASK 49-32-41-920-002-A	Replacement of the Fuel Filter (APS 3200)
TASK 52-41-00-010-001-A	Open the APU Doors for Access
TASK 52-41-00-410-001-A	Close the APU Doors after Access

3. Job Set-up
Subtask 49-31-00-860-067-A ** ON A/C NOT FOR ALL

A. Safety Precautions

WARNING: OBEY THE FUEL SAFETY PROCEDURES.

(1) Obey the fuel safety procedures (Ref. AMM TASK 28-00-00-910-001).
(2) If the fuel temperature is less than 0 deg.C (32.00 deg.F), water in the fuel tank (and/or the water drain valves) can be frozen. To make sure the water drain valves are not frozen:
(a) Do the cold weather maintenance practice for the fuel system (Ref. AMM TASK 12-31-28-660-001).

NOTE: Do not use too much force to operate the water drain valves.

Subtask 49-31-00-860-068-A ** ON A/C NOT FOR ALL

B. Aircraft Maintenance Configuration
(1) Put a WARNING NOTICE(S) in position on the overhead panel 25VU to tell persons not to start the APU.
(2) Energize the ground service network
(Ref. AMM TASK 24-42-00-861-001).
(3) Put the related hydraulic system in the depressurized configuration (Ref. AMM TASK 29-00-00-864-001).

Subtask 49-31-00-010-067-A ** ON A/C NOT FOR ALL

C. Get access to the avionics compartment.
(1) Put the ACCESS PLATFORM 3M (10 FT)- ADJUSTABLE in position below access door 811.
(2) Open access door 811.

Subtask 49-31-00-865-068-A ** ON A/C NOT FOR ALL

D. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/FIRE AND OVHT/DET/LOOP B	2WG	L44
121VU	APU/FIRE AND OVHT/DET/LOOP A	1WG	L43
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41
121VU	APU/FIRE/EXTIG/SQUIB/B	2WF	L39
121VU	APU/FIRE/EXTIG/SQUIB/A	1WF	L38

Subtask 49-31-00-010-069-A ** ON A/C NOT FOR ALL

E. Get Access
(1) Put the ACCESS PLATFORM 8M (26 FT) - ADJUSTABLE in position below the APU compartment.
(2) Open APU access doors 315AL and 316AR and safety them in the open position (Ref. AMM TASK 52-41-00-010-001).
(3) Set LIGHT switch 11LJ to the ON position.

4. Procedure
Subtask 49-31-00-281-069-A ** ON A/C NOT FOR ALL

A. Fuel Sampling for Hydraulic Contamination
(1) Get a sample of fuel to do the contamination test (Ref. AMM TASK 12-32-28-281-802).

If you do not do the analysis immediately, seal the container.

Subtask 49-31-00-281-073-A ** ON A/C NOT FOR ALL

B. Fuel Contamination Test
(1) Get the information that follows to find the level of contamination:

Date of samples
APU operation times after the detection of the contamination
Time before the next scheduled maintenance revision.

(2) Make an analysis of the test results:
(a) If the concentration of the hydraulic fluid in the fuel is less than 0.0001 per cent:

The hydraulic fluid contamination of the fuel is acceptable for normal APU operation.

(b) If the hydraulic fluid contamination of the fuel is more than the permitted limits for a normal APU operation, the APU can operate in the conditions that follow:

If the fuel contamination is less than 0.5 per cent, the APU can operate for a maximum of ten hours before maintenance.
If the fuel contamination is between 0.5 and 2 per cent, the APU can operate for a maximum of three hours before maintenance.
If the fuel contamination is more than 2 per cent, the APU can operate for a maximum of one hour before maintenance.

Subtask 49-31-00-280-050-A ** ON A/C NOT FOR ALL

C. Return to Service
(1) If there is contamination more than 0.0001 per cent:
(a) Drain and flush the aircraft fuel tanks and lines until the concentration of hydraulic fluid at the APU inlet is less than 0.1 per cent (in weight).

Add fuel until the hydraulic fluid concentration in the fuel is less than 0.0001 per cent.

(b) Do an Inspection of the fluorosilicone seal of the APU fuel-filter bowl.
1 If the seal exceeds specification requirements and it is expanded:

Replace all the fluorosilicone seals in the APU fuel system.
Remove the APU fuel control and filter and send them to the shop (Ref. AMM TASK 49-32-11-000-002) (Ref. AMM TASK 49-32-11-400-002) (Ref. AMM TASK 49-32-41-920-002).

(c) Do an inspection of the fuel nozzles for signs of clogging (Ref. AMM TASK 49-31-41-200-003) (Ref. AMM TASK 49-31-42-200-005).
1 If you find clogging, replace the fuel nozzles (Ref. AMM TASK 49-31-41-000-002) (Ref. AMM TASK 49-31-41-400-002) (Ref. AMM TASK 49-31-42-000-003) (Ref. AMM TASK 49-31-42-400-005).

5. Close-up
Subtask 49-31-00-410-065-A ** ON A/C NOT FOR ALL

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Set LIGHT switch 11LJ to the OFF position.
(3) Close APU access doors 315AL and 316AR (Ref. AMM TASK 52-41-00-410-001).
(4) Remove the access platform(s).

Subtask 49-31-00-865-069-A ** ON A/C NOT FOR ALL

B. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C NOT FOR ALL
121VU	APU/FIRE AND OVHT/DET/LOOP B	2WG	L44
121VU	APU/FIRE AND OVHT/DET/LOOP A	1WG	L43
121VU	APU/APU/CTL	2KD	L42
121VU	APU/ECB/SPLY	1KD	L41
121VU	APU/FIRE/EXTIG/SQUIB/B	2WF	L39
121VU	APU/FIRE/EXTIG/SQUIB/A	1WF	L38

Subtask 49-31-00-410-066-A ** ON A/C NOT FOR ALL

C. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Close access door 811.
(3) Remove the access platform(s).

Subtask 49-31-00-860-069-A ** ON A/C NOT FOR ALL

D. Put the aircraft back to its initial configuration.
(1) Make sure that the hydraulic system is back to the initial configuration (Ref. AMM TASK 29-00-00-864-001).
(2) De-energize the ground service network
(Ref. AMM TASK 24-42-00-862-001).
(3) Remove the WARNING NOTICE(S).
(4) Remove the ground support and maintenance equipment, the special and standard tools and all other items.

[Rev.10 from 2021] 2026.04.01 01:29:27 UTC