Drain Mast Leakage Identification Procedure [CFMB]

TASK 71-00-00-790-005-A
Drain Mast Leakage Identification Procedure

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

REFERENCE	QTY	DESIGNATION
No specific	AR	ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE
No specific	AR	BOTTLE - PLASTIC
98F10103500000	2	CHOCK-MLG,ENGINE RUN-UP

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
FOR [1000EM1] (ENGINE-1)
437AL, 438AR, 451AL, 452AR
FOR [1000EM2] (ENGINE-2)
447AL, 448AR, 461AL, 462AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 71-00-00-710-003-B	Engine Automatic Start
TASK 71-00-00-710-028-B	Engine Shutdown
TASK 71-00-00-790-002-B	Fuel or Hydraulic or Oil Leakage Limits
TASK 71-00-00-869-003-A	Wind Limitations During Engine Ground Operations
TASK 71-00-00-869-004-A	Safety Precautions During Engine Ground Operations
TASK 71-13-00-010-040-B	Opening of the Fan Cowl Doors
TASK 71-13-00-410-040-B	Closing of the Fan Cowl Doors
TASK 71-71-43-000-041-A	Removal of the Drain Manifold Module
TASK 71-71-43-400-041-A	Installation of the Drain Manifold Module
TASK 78-30-00-081-041-B	Make the Thrust Reverser Serviceable after Maintenance
TASK 78-30-00-481-041-B	Make the Thrust Reverser Unserviceable for Maintenance
TASK 78-36-00-010-040-B	Opening of the Thrust Reverser Doors
TASK 78-36-00-410-040-B	Closing of the Thrust Reverser Doors
TASK 71-70-00-00-06	POWER PLANT DRAINS - DESCRIPTION AND OPERATION
Tool Installation

3. Job Set-up
Subtask 71-00-00-010-105-A ** ON A/C NOT FOR ALL

Subtask 71-00-00-040-072-A ** ON A/C NOT FOR ALL

B. Make the thrust reverser unserviceable (Ref. AMM TASK 78-30-00-481-041).

Subtask 71-00-00-010-106-A ** ON A/C NOT FOR ALL

C. Open the thrust reverser doors (Ref. AMM TASK 78-36-00-010-040):
(1) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(2) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 71-00-00-869-199-A ** ON A/C NOT FOR ALL

D. Prepare for Test

NOTE: For identification of the specific drain line on affected engines, refer to the applicable Description and Operation (Ref. AMM D/O 71-70-00-00).

(1) For source identification of a fuel leak at the drain mast:
(a) Disconnect the fuel tubes that can cause fuel leaks (Ref. AMM TASK 71-71-43-000-041).
(b) Install the BOTTLE - PLASTIC and tubes on all the possible fuel leakage sources.

NOTE: For identification of a static fuel leak, the VBV gear motor must be disconnected first (this is the most likely accessory to be suspect).

(2) For source identification of an oil leak at the drain mast:
(a) Disconnect the oil tubes that can cause oil leaks (Ref. AMM TASK 71-71-43-000-041).
(b) Install the BOTTLE - PLASTIC and tubes on all the possible oil leakage sources.
(3) Safety precautions:
(a) Obey the wind limitations and safety precautions during engine ground operation (Ref. AMM TASK 71-00-00-869-003) and (Ref. AMM TASK 71-00-00-869-004).
(b) Make sure that the 98F10103500000 CHOCK-MLG,ENGINE RUN-UP are in position in front of each forward outboard MLG wheel.

Tool Installation ** ON A/C NOT FOR ALL

(c) There must be two qualified persons in the cockpit when performing an engine run. One must monitor the outside and the aircraft behavior while the other performs the engine test.
(d) If the aircraft begins to move while performing an engine run, immediately set all the thrust levers to the idle position.

Subtask 71-00-00-410-102-A ** ON A/C NOT FOR ALL

E. Close Access
(1) Close the thrust reverser doors (Ref. AMM TASK 78-36-00-410-040):
(2) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(3) FOR [1000EM2] (ENGINE-2)
461AL 462AR
(4) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-040):
(5) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(6) FOR [1000EM2] (ENGINE-2)
447AL 448AR

4. Procedure
Subtask 71-00-00-790-060-A ** ON A/C NOT FOR ALL

A. To Identify the Source of the Leak at the Drain Mast

WARNING: - ENGINE OPERATION MUST NOT EXCEED MINIMUM IDLE WHEN PERSONNEL ARE IN ENTRY/EXIT CORRIDOR.

POSITIVE COMMUNICATION BETWEEN THE FLIGHT COMPARTMENT AND PERSONNEL IN ENTRY EXIT CORRIDOR IS NECESSARY.
INLET AND EXHAUST HAZARD AREAS MUST BE STRICTLY OBSERVED BY PERSONNEL IN ENTRY/EXIT CORRIDOR.

(1) To check for fuel leaks at the drain mast, do the following steps:
(a) Start the engine (Ref. AMM TASK 71-00-00-710-003).
(b) Let the engine become stable at minimum idle for 5 minutes.
(c) Shut-down the engine (Ref. AMM TASK 71-00-00-710-028).
(2) To check for oil leaks at the drain mast, do the following steps:
(a) Start both engines (Ref. AMM TASK 71-00-00-710-003).
(b) Let the engines become stable at minimum idle for 5 minutes.
(c) Slowly increase power of the non-tested engine to 60 percent N1.
(d) Slowly accelerate the tested engine and stabilize at 70 percent N1 for 5 minutes.
(e) Slowly decrease power on the two engines to minimum idle and let became stable for 5 minutes.
(f) Shut-down the engines (Ref. AMM TASK 71-00-00-710-028).
(3) Measure the individual leakage quantities collected from each plastic bottle. For the fuel, oil and hydraulic fluid leakage limits (Ref. AMM TASK 71-00-00-790-002).

5. Close-up
Subtask 71-00-00-010-107-A ** ON A/C NOT FOR ALL

A. Get Access
(1) Open the fan cowl doors (Ref. AMM TASK 71-13-00-010-040):
(2) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(3) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(4) Put the ACCESS PLATFORM 2M (6 FT) - ADJUSTABLE in position.
(5) Open the thrust reverser doors (Ref. AMM TASK 78-36-00-010-040):
(6) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(7) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 71-00-00-869-200-A ** ON A/C NOT FOR ALL

B. Reconnection of Drain Lines
(1) Remove the plastic bottles and tubes.
(2) Reconnect the drain lines.
(a) Reconnect the fuel tubes (Ref. AMM TASK 71-71-43-400-041).
(b) Reconnect the oil tubes (Ref. AMM TASK 71-71-43-400-041).

Subtask 71-00-00-410-103-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 the thrust reverser doors (Ref. AMM TASK 78-36-00-410-040):
(3) FOR [1000EM1] (ENGINE-1)
451AL 452AR
(4) FOR [1000EM2] (ENGINE-2)
461AL 462AR

Subtask 71-00-00-440-070-A ** ON A/C NOT FOR ALL

D. Make the thrust reverser serviceable (Ref. AMM TASK 78-30-00-081-041).

Subtask 71-00-00-410-104-A ** ON A/C NOT FOR ALL

E. Close Access
(1) Close the fan cowl doors (Ref. AMM TASK 71-13-00-410-040):
(2) FOR [1000EM1] (ENGINE-1)
437AL 438AR
(3) FOR [1000EM2] (ENGINE-2)
447AL 448AR
(4) Remove the access platform(s).

[Rev.10 from 2021] 2026.04.01 02:24:57 UTC