Fuel or Hydraulic or Oil Leakage Limits [CFMB]

TASK 71-00-00-790-002-B
Fuel or Hydraulic or Oil Leakage Limits

1. Reason for the Job
Self explanatory
2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TASK 29-00-00-790-001-A	Check of the External Leaks of the Hydraulic Components
TASK 71-00-00-710-003-B	Engine Automatic Start
TASK 71-00-00-790-002-B	Fuel or Hydraulic or Oil Leakage Limits
TASK 71-00-00-790-005-A	Drain Mast Leakage Identification Procedure
TASK 72-00-00-200-008-A	Inspection/Check After the Engine has Exceeded the Operational Limits
TASK 72-63-00-300-002-A	Replacement of a Sealol Seal (IDG and Starter Drive Pads)
TASK 72-63-00-300-003-A	Replacement of a Magnetic Seal (Fuel Pump and Hydraulic Pump Drive Pads)
TASK 72-63-00-300-004-A	Replacement of a Magnetic Seal (IDG and Starter Drive Pads).
TASK 72-63-00-300-802-A	Replacement of a Sealol Seal (Fuel Pump and Hydraulic Pump Drive Pads)
TASK 73-11-10-000-003-A	Removal of the Fuel Pump and Filter Assembly
TASK 73-11-10-400-003-A	Installation of the Fuel Pump and Filter Assembly
TASK 73-11-31-000-041-A	Removal of the Fuel Manifold Gasket Seals
TASK 73-11-40-790-002-A	Leak Check of the Fuel Nozzles for SAC Engines
TASK 73-11-40-790-002-A-01	Leak Check of the Fuel Nozzles for DAC Engines
TASK 73-21-10-000-002-A	Removal of the Hydromechanical Unit (HMU)
TASK 73-21-10-400-002-A	Installation of the Hydromechanical Unit (HMU)
TASK 75-21-10-000-002-A	Removal of the High Pressure Turbine Active Clearance Control (HPTACC) Valve
TASK 75-21-10-400-002-A	Installation of the High Pressure Turbine Active Clearance Control (HPTACC) Valve
TASK 75-22-10-000-002-A	Removal of the Low Pressure Turbine Active Clearance Control (LPTACC) Valve
TASK 75-22-10-400-002-A	Installation of the Low Pressure Turbine Active Clearance Control (LPTACC) Valve
TASK 75-23-10-000-002-A	Removal of the Rotor Active Clearance Start Bleed Valve
TASK 75-23-10-400-002-A	Installation of the Rotor Active Clearance Start Bleed Valve
TASK 75-31-10-000-002-A	Removal of the Bleed Valve Fuel Gear Motor Assembly
TASK 75-31-10-400-002-A	Installation of the Bleed Valve Fuel Gear Motor Assembly
TASK 75-32-10-000-002-A	Removal of the Variable Stator Vane (VSV) Actuators
TASK 75-32-10-400-002-A	Installation of the Variable Stator Vane (VSV) Actuators
TASK 79-00-00-210-006-A	Visual Inspection of the Aft Sump Oil System
TASK 79-21-20-000-002-A	Removal of the Main Oil/Fuel Heat Exchanger
TASK 79-21-20-400-002-A	Installation of the Main Oil/Fuel Heat Exchanger
Check of Fuel Leak at the Aircraft Drain Mast Assembly

3. Job Set-up
Subtask 71-00-00-869-202-A ** ON A/C NOT FOR ALL

A. Not Applicable

4. Procedure
Subtask 71-00-00-790-053-B ** ON A/C NOT FOR ALL

CAUTION: NO LEAKAGE PERMITTED FROM THE FUEL MANIFOLD SHROUD DRAIN LINE.

A. Leakage at the Drain Mast

NOTE: For identification of this specific drain line on affected engines (Refer to 71-70-00).

WARNING: USE THERMAL GLOVES WHEN YOU MOVE OR TOUCH HOT OR COLD PARTS. HOT OR COLD PARTS CAN CAUSE INJURY.

CAUTION: DO NOT LET THE HMU TEMPERATURE BE MORE THAN 100 DEG. C (212 DEG. F).

(1) Safety Precautions:

NOTE: Hydromechanical Units (HMUs) that have fluorocarbon (Viton) external seals (CFM SB 73-015) can leak fuel for a short time when they are below 0 deg.C (32.00 deg.F) (Modifications 1 and 2) (Ref. AMM TASK 71-00-00-790-002). If the ambient temperature is below -40 deg.C (-40.00 deg.F), it is recommended to heat the HMU (Modifications 1 and 2) to minimize leakage during starts by applying the following procedure.

(a) Heat the HMU housing with a suitable hot air blower (Keco GH100, Aerotech BT400-45 or equivalent) operating at 140 deg.C (284.00 deg.F) until the HMU housing temperature is more than 25 deg.C (77.00 deg.F).

If the fuel leakage stops in less than five minutes at idle, continue operation of the engine.
If the fuel leakage continues after five minutes at idle, shut down the engine and repair the source of the leakage.

(2) Fuel leak at the aircraft drain mast assembly:
(a) With non-running engine (Static fuel leak), do a check at the aircraft drain mast assembly:
1 If the fuel leakage rate is less than 60 drops per minute (180 ml/hr or 3 cc/min), you do not have maintenance action.

Check of Fuel Leak at the Aircraft Drain Mast Assembly ** ON A/C NOT FOR ALL

2 If the fuel leakage rate is more than 60 drops per minute (180 ml/hr or 3 cc/min), do the actions required:

Check of Fuel Leak at the Aircraft Drain Mast Assembly ** ON A/C NOT FOR ALL

Start the engine (Ref. AMM TASK 71-00-00-710-003)
Let the engine become stable at min idle for five minutes
Check the leakage rate.

NOTE: In the case of extreme cold weather condition (Outside Air Temperature (OAT)<- 20 deg.C (- 4 deg.F)), fuel leaks from the drain mast (other than fuel manifold drain) may occur on a non-running engine and during engine start (cold engine condition). This leakage can stop after a 5-minute warm-up at minimum idle.

(b) With running engine (Dynamic fuel leak), do a check at the aircraft drain mast assembly (After 5-minute warm-up at minimum idle):
1 If the fuel leakage rate is less than 60 drops per minute (180 ml/hr or 3 cc/min), you do not have maintenance action.

Check of Fuel Leak at the Aircraft Drain Mast Assembly ** ON A/C NOT FOR ALL

2 If the fuel leakage rate is more than 60 drops per minute (180 ml/hr or 3 cc/min), but less than 90 drops per minute (270 ml/hr or 4.5 cc/min), do a corrective action within 25 cycles not interfering with revenue service operation.

Check of Fuel Leak at the Aircraft Drain Mast Assembly ** ON A/C NOT FOR ALL

3 If the fuel leakage rate is more than 90 drops per minute (270 ml/hr or 4.5 cc/min), do a leakage test (Ref. AMM TASK 71-00-00-790-005) to identify the defective element.

Check of Fuel Leak at the Aircraft Drain Mast Assembly ** ON A/C NOT FOR ALL

(3) Oil leakage at the drain mast assembly:
(a) If the oil leakage rate at the drain mast assembly is less than 7 drops per minute (20 ml/hr or 1 cc/3 min), you do not have maintenance action.
(b) If the oil leakage rate at the drain mast assembly is more than 7 drops per minute (20 ml/hr or 1 cc/3 min), do a leakage test (Ref. AMM TASK 71-00-00-790-005).
(4) Hydraulic leakage at the drain mast assembly (Ref. AMM TASK 29-00-00-790-001).
(5) Measure the individual leak quantities and look for the items that follow:

INSPECT/CHECK	MAXIMUM SERVICEABLE LIMITS	REMARKS
1.The oil source
The starter pad	20 ml/hr (1cc/3min) (7 drops/min)	Replace the seal (Ref. AMM TASK 72-63-00-300-002) or (Ref. AMM TASK 72-63-00-300-004).
The AGB rear hydraulic pump pad	20 ml/hr (1cc/3min) (7 drops/min)	Replace the seal (Ref. AMM TASK 72-63-00-300-003) or (Ref. AMM TASK 72-63-00-300-802).
The AGB fuel pump pad	20 ml/hr (1cc/3min) (7 drops/min)	Replace the seal (Ref. AMM TASK 72-63-00-300-003) or (Ref. AMM TASK 72-63-00-300-802).
The lube unit pad	No leaks allowed
The main oil/fuel heat exchanger	20 ml/hr (1cc/3min) (7 drops/min)	Replace the main oil/fuel heat exchanger (Ref. AMM TASK 79-21-20-000-002) and (Ref. AMM TASK 79-21-20-400-002).
The AGB/IDG pad	20 ml/hr (1cc/3min) (7 drops/min)	Replace the seal (Ref. AMM TASK 72-63-00-300-002) or (Ref. AMM TASK 72-63-00-300-004).
The forward sump	60 ml/hr (1cc/min) (20 drops/min)	Replace the engine.
The aft sump (flooding drain)	Any amount, during the engine motoring (start, cranking) and after the engine shutdown, if the oil consumption rate and oil pressure are within the serviceable limits (Ref. AMM TASK 72-00-00-200-008).	Replace the engine. NOTE: During the engine motoring, the engine oil supply pressure increases more quickly than the sump air pressure. When N2 is high enough to get a positive oil supply pressure, it is normal that a volume of oil goes through the aft sump rotating seals for a short periods of time, until the sump air pressure is high enough. This oil is drained through the overboard drain. Some oil will also be drained during the engine shutdown.
The aft sump area	No leak allowed	Do a visual inspection of the aft sump area (Ref. AMM TASK 79-00-00-210-006). NOTE: You must think that oil puddling in the exhaust/aft sump area/centerbody is normal as long as the oil consumption rate is within serviceable limits.
2.The fuel source
The fuel manifold shroud	No leaks allowed	Do a leak check at the manifold assembly (Ref. AMM TASK 73-11-40-790-002).
Fuel pump at the AGB drive pad	180 ml/hr (3 cc/min) (60 drops/min) (up to 90 drops/min allowed for 25 cycles)	Replace the fuel pump (Ref. AMM TASK 73-11-10-000-003) and (Ref. AMM TASK 73-11-10-400-003). NOTE: The heat exchanger, VSV actuator(s), VBV fuel gear motor, HPTCC valve, LPTCC valve, RACC valve, HMU and the fuel distribution block share the same fuel drain line at the drain mast manifold. There may be more than one unit leaking. To isolate the unit leaking, disconnect the drain tubes at each component.
Heat exchanger	180 ml/hr (3 cc/min) (60 drops/min) (up to 90 drops/min allowed for 25 cycles)	Replace the main oil/fuel heat exchanger (Ref. AMM TASK 79-21-20-000-002) and (Ref. AMM TASK 79-21-20-400-002).
VSV actuator(s) (LH or RH)	180 ml/hr (3 cc/min) (60 drops/min) (up to 90 drops/min allowed for 25 cycles)	Replace the VSV actuator(s) (Ref. AMM TASK 75-32-10-000-002) and (Ref. AMM TASK 75-32-10-400-002).
VBV fuel gear motor	180 ml/hr (3 cc/min) (60 drops/min) (up to 90 drops/min allowed for 25 cycles)	Replace the VBV fuel gear motor (Ref. AMM TASK 75-31-10-000-002) and (Ref. AMM TASK 75-31-10-400-002).
HPTACC valve	180 ml/hr (3 cc/min) (60 drops/min) (up to 90 drops/min allowed for 25 cycles)	Replace the HPTACC valve (Ref. AMM TASK 75-21-10-000-002) and (Ref. AMM TASK 75-21-10-400-002).
LPTACC valve	180 ml/hr (3 cc/min) (60 drops/min) (up to 90 drops/min allowed for 25 cycles)	Replace the LPTACC valve (Ref. AMM TASK 75-22-10-000-002) and (Ref. AMM TASK 75-22-10-400-002).
RACC valve	180 ml/hr (3 cc/min) (60 drops/min) (up to 90 drops/min allowed for 25 cycles)	Replace the RACC valve (Ref. AMM TASK 75-23-10-000-002) and (Ref. AMM TASK 75-23-10-400-002).
Fuel manifold	180 ml/hr (3 cc/min) (60 drops/min) (up to 90 drops/min allowed for 25 cycles)	Replace the Fuel manifold seals (Ref. AMM TASK 73-11-31-000-041).
HMU	180 ml/hr (3 cc/min) (60 drops/min) (up to 90 drops/min allowed for 25 cycles)	Replace the HMU (Ref. AMM TASK 73-21-10-000-002) and (Ref. AMM TASK 73-21-10-400-002).
3.The hydraulic source
The hydraulic pump pad	(Ref. AMM TASK 29-00-00-790-001)

[Rev.10 from 2021] 2026.04.01 02:24:56 UTC