Check of the External Leaks of the Hydraulic Components

TASK 29-00-00-790-001-A
Check of the External Leaks of the Hydraulic Components

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

WARNING: OBEY THE HYDRAULIC SAFETY PROCEDURES.

WARNING: DO NOT GET HYDRAULIC FLUID ON YOUR SKIN, IN YOUR EYES OR IN YOUR MOUTH. HYDRAULIC FLUID IS POISONOUS AND CAN GO THROUGH YOUR SKIN AND INTO YOUR BODY. FLUSH HYDRAULIC FLUID FROM YOUR EYES, MOUTH OR SKIN WITH WATER. GET MEDICAL AID IF YOU GET HYDRAULIC FLUID IN YOUR EYES OR MOUTH.

1. Reason for the Job
To make sure that, external leaks, leakage and stains of the hydraulic components are in the specified limits.

NOTE: The definitions of the terms used in this procedure are:

A leak is the quantity of fluid that comes out of a component that is sufficient to become a drop or drops, or will possibly become a drop (approximately 20 drops = 1 cc, 75600 drops = 1 gallon)
A leakage is a quantity of fluid on the surface of a component that is not sufficient to become a drop
A stain is an area on the surface of a component that has a different color. It is usually caused when fluid leakage dries on the component surface after high temperature operation.

NOTE: The hydraulic fluid leakage from the Normal Braking System is not permitted, because of the possible effects on aircraft safety.

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
TASK 12-14-29-614-001-A	Fill the Hydraulic Power Accumulators with Nitrogen
TASK 12-32-28-281-802-A	Sample Fuel for Hydraulic-Oil Contamination Analysis
TASK 27-26-51-000-001-A	Removal of the Yaw Damper Servo Actuator
TASK 27-26-51-200-001-A	Inspection of the Rudder Yaw Damper Servo-Actuator for Leakage
TASK 27-26-51-400-001-A	Installation of the Yaw Damper Servo Actuator
TASK 29-00-00-280-006-A	Check of the Green or Yellow Hydraulic System after Engine Pump Failure or Operation in a Possible Cavitation Condition - with Ground Cart Available
TASK 29-00-00-280-006-A-01	Check of the Green or Yellow Hydraulic System after Engine Pump Failure or Operation in a Possible Cavitation Condition - Ground Cart not Available
TASK 29-10-00-863-001-A	Pressurize the Green Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-863-002-A	Pressurize the Yellow Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-863-003-A	Pressurize the Blue Hydraulic System with a Hydraulic Ground Power-Cart
TASK 29-10-00-863-003-A-01	Pressurize the Blue Hydraulic System with the Blue Electric Pump
TASK 29-10-00-864-001-A	Depressurize the Green Hydraulic System
TASK 29-10-00-864-002-A	Depressurize the Yellow Hydraulic System
TASK 29-10-00-864-003-A	Depressurize the Blue Hydraulic System
TASK 29-11-21-000-001-A	Removal of the Accumulator-Air Pressure Gage
TASK 29-11-21-400-001-A	Installation of the Accumulator-Air Pressure Gage
TASK 29-11-42-000-001-A	Removal of the Green Power Accumulator
TASK 29-11-42-400-001-A	Installation of the Green Power Accumulator
TASK 29-12-21-000-001-A	Removal of the Accumulator-Air Pressure Gage
TASK 29-12-21-400-001-A	Installation of the Accumulator-Air Pressure Gage
TASK 29-12-42-000-001-A	Removal of the Blue Power Accumulator
TASK 29-12-42-400-001-A	Installation of the Blue Power Accumulator
TASK 29-13-21-000-001-A	Removal of the Accumulator-Air Pressure Gage
TASK 29-13-21-400-001-A	Installation of the Accumulator-Air Pressure Gage
TASK 29-13-42-000-001-A	Removal of the Yellow Power Accumulator
TASK 29-13-42-400-001-A	Installation of the Yellow Power Accumulator
TASK 29-23-00-863-001-A	Pressurize the Green Hydraulic System from the Yellow Hydraulic System through the PTU with the Electric Pump
TASK 29-23-00-864-001-A	Depressurize the Green and Yellow Hydraulic Systems after Operation of the PTU
TASK 32-44-11-000-001-A	Removal of the Accumulator
TASK 32-44-11-400-001-A	Installation of the Accumulator
TASK 32-44-13-000-001-A	Removal of the Charging Valve
TASK 32-44-13-400-001-A	Installation of the Charging Valve
TASK 32-44-14-000-001-A	Removal of the Accumulator Pressure Gage
TASK 32-44-14-400-001-A	Installation of the Accumulator Pressure Gage
TASK 32-44-17-000-001-A	Removal of the Brake Manifold
TASK 32-44-17-400-001-A	Installation of the Brake Manifold
TASK 51-78-00-615-002-A	Aircraft Cleaning after a Hydraulic Fluid Leakage
TASK 71-00-00-710-001-A	Dry Motoring Check
TASK 71-00-00-710-001-B	Dry Motoring Check
TASK 71-00-00-710-045-A	Test No.1 : Dry Motor Leak Check
TASK 71-00-00-720-809-A	Test No. 2 - Engine Motor Leak Test (Dry Method)
TASK 71-00-00-790-001-A	Leak Test of the Accessory-Gearbox (AGB) Carbon Seal
TASK 71-00-00-790-001-B	Leak Test of the Accessory-Gearbox (AGB) Carbon Seal
TASK 71-00-00-790-004-A	Leak Check after the Replacement of a Sealol Seal or a Magnetic Seal on the AGB Drive Pads of the IDG, Hydraulic Pump, Starter and Fuel Pump
TASK 71-00-00-790-006-A	Leak Check after the Replacement of a Sealol Seal or a Magnetic Seal on the AGB Drive Pads of the IDG, Hydraulic Pump, Starter and Fuel Pump
Flow Chart of Check of the External Leaks of the Hydraulic Components

3. Job Set-up
Subtask 29-00-00-910-052-A

A. Standard Practices
(1) If you do the check of external leaks because a complete loss of the hydraulic system has occurred and the:

RSVR LO LVL warning on the upper ECAM DU of the related hydraulic system is ON
Engine driven pump is operated for more than 5 minutes.

(a) You must do the check of the Green and/or Yellow hydraulic system after operation in a possible cavitation condition of the engine pump (Ref. AMM TASK 29-00-00-280-006).
(2) For a correct analysis of component leak rates and leakage checks, you must obey the subsequent steps:
(a) Before you do a check on a hydraulic system that has not operated during its time in storage, you must:

Pressurize the system and operate the components
Remove all the signs of hydraulic fluid leaks and clean the surface of the components.

(b) Hydraulic tube connections seal when you force the metal-to-metal surfaces of the component parts together. If you find a leak at a hydraulic tube connection, you must tighten the nut to the specified torque. If the leak continues, you must replace the defective components.
(c) Operate the components for some cycles before you do an external leak check.
(d) Do a check of the dynamic seals of pistons, slide valves and swivel joints with the system pressurized, but do not operate the components. The dynamic seals move only with a short time interval, and some cannot easily be monitored when they operate.
(e) If you think that there is a problem with the MLG extension/retraction components, do the procedure as follows:

Do not apply a full system pressure during fault isolation because of the possible safety effects
Apply the system pressure gradually to find a leak.

NOTE: The crack of the actuator can cause a large leak.

Subtask 29-00-00-010-050-A

B. Get Access
(1) Inspect the external surface of the Aircraft for signs of the hydraulic leak.
(2) Get access to the applicable component.

Subtask 29-00-00-941-050-A

C. Preparation for Check
(1) If the component has a seal drain connection, disconnect the drain pipe from it.

NOTE: The motors of the Trimmable Horizontal Stabilizer (THS) actuator have seal drain connections, but do not have related drain pipes.

(2) Make sure that the surface of the component is clean and that you remove all the hydraulic fluid and the fluid stains.
(3) Put a piece of cloth or paper below the component, to absorb the fluid. Make sure that it does not touch parts which turn or move.

4. Procedure
Subtask 29-00-00-863-050-A ** ON A/C NOT FOR ALL

A. Pressurization of the Hydraulic System

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(1) Pressurize the necessary hydraulic system(s):

For the Green hydraulic system (Ref. AMM TASK 29-10-00-863-001) or (Ref. AMM TASK 29-23-00-863-001)
For the Yellow hydraulic system (Ref. AMM TASK 29-10-00-863-002)
For the Blue hydraulic system (Ref. AMM TASK 29-10-00-863-003).

(2) If it is necessary to do a check of the external leaks of the engine driven pumps, do an engine run of the applicable engine
(Ref. AMM TASK 71-00-00-720-809).

Subtask 29-00-00-863-050-B ** ON A/C NOT FOR ALL

A. Pressurization of the Hydraulic System

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(1) Pressurize the necessary hydraulic system(s):

For the Green hydraulic system (Ref. AMM TASK 29-10-00-863-001) or (Ref. AMM TASK 29-23-00-863-001)
For the Yellow hydraulic system (Ref. AMM TASK 29-10-00-863-002)
For the Blue hydraulic system (Ref. AMM TASK 29-10-00-863-003).

(2) If it is necessary to do a check of the external leaks of the engine driven pumps, do an engine run of the applicable engine (Ref. AMM TASK 71-00-00-790-001), (Ref. AMM TASK 71-00-00-710-001) and (Ref. AMM TASK 71-00-00-790-006).

Subtask 29-00-00-863-050-D ** ON A/C NOT FOR ALL

A. Pressurization of the Hydraulic System

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

CAUTION: DURING GROUND RUNNING, CONCERN FOR FAN BLADE INTEGRITY PROHIBITS STABILISED ENGINE OPERATION IN THE FOLLOWING SPEED RANGE:

FOR PRE-SCN17/V A/C: DO NOT STABILISE THE ENGINE BETWEEN 61% TO 74% N1 SPEED RANGE
FOR POST-SCN17/V A/C: STABILISED OPERATION OF THE ENGINE BETWEEN APPROXIMATELY 60% TO 74% N1 SPEED RANGE (LIMITS ARE A FUNCTION OF OUTSIDE TEMPERATURE) WILL BE PROHIBITED BY THE EEC, AS THE SOFTWARE INCLUDES THE KEEP-OUT-ZONE FOR ON-GROUND, STATIC OPERATION.

(1) Pressurize the necessary hydraulic system(s):

For the Green hydraulic system (Ref. AMM TASK 29-10-00-863-001) or (Ref. AMM TASK 29-23-00-863-001)
For the Yellow hydraulic system (Ref. AMM TASK 29-10-00-863-002)
For the Blue hydraulic system (Ref. AMM TASK 29-10-00-863-003).

(2) If it is necessary to do a check of the external leaks of the engine driven pumps, do an engine run of the applicable engine (Ref. AMM TASK 71-00-00-710-045).

Subtask 29-00-00-863-050-E ** ON A/C NOT FOR ALL

A. Pressurization of the Hydraulic System

WARNING: MAKE SURE THAT THE TRAVEL RANGES OF THE FLIGHT CONTROLS SURFACES ARE CLEAR. MOVEMENT OF FLIGHT CONTROLS CAN CAUSE INJURY TO PERSONS AND/OR DAMAGE TO EQUIPMENT.

(1) Pressurize the necessary hydraulic system(s):

For the Green hydraulic system (Ref. AMM TASK 29-10-00-863-001) or (Ref. AMM TASK 29-23-00-863-001)
For the Yellow hydraulic system (Ref. AMM TASK 29-10-00-863-002)
For the Blue hydraulic system (Ref. AMM TASK 29-10-00-863-003).

Subtask 29-00-00-790-050-C

B. External Leak Test of the Component

Flow Chart of Check of the External Leaks of the Hydraulic Components

(1) Operate the component.
(2) Do an inspection of the component for external leaks. If you find leaks, you must compare the quantity of the leaks with the values given in the table below:

NOTE: The table that follows is applicable only for Green, Yellow and Blue Hydraulic Systems. It is not applicable for Alternate-Braking Low-Pressure System.

Equipment	Normal Operation Limit	Dispatch Limit to Prevent Delay	See Notes
1. HYDRAULIC PUMP
Engine Driven Pump (EDP)			NOTE 6.
Electric Motor Pump (EMP)			NOTE 6.
Ram Air Turbine (RAT)			NOTE 6.
Power Transfer Unit (PTU)			NOTE 6.
Static Seals (at Unions and Connections)	No leakage	2 drops in 10 min	NOTE 6.
Static Casing (Housing)	1 drop in 10 min	1 drop/min	NOTE 6.
Shaft Seal (system pressurized)	2 drops/min	8 drops/min	NOTE 6.
Shaft Seal (in operation)	EDP: 5 drops/min EMP: 5 drops/min RAT: 1 drop/min PTU: 5 drops/min	EDP: 60 drops/min EMP: 30 drops/min RAT: 1 drop/min PTU: 30 drops/min	NOTE 6. NOTE 6. NOTE 6. NOTE 6.
2. SERVOCONTROL
Elevator			NOTE 6.
Aileron			NOTE 6.
Rudder			NOTE 6.
Spoiler			NOTE 6.
Yaw Damper			NOTE 4. and NOTE 6.
Static Seal (system pressurized)	No leakage	2 drops in 10 min	NOTE 6.
Dynamic Seal (system pressurized)	1 drop in 10 min	Elevator: 6 drops in 10 min. Aileron: 6 drops in 10 min. Rudder : 30 drops/min. Spoiler: 30 drops/min.	NOTE 1. and NOTE 6. NOTE 1. and NOTE 6. NOTE 6. NOTE 6.
Dynamic Seal (in operation)	1 drop in 10 cycles	Elevator: 3 drops in 10 cycles Aileron: 3 drops in 10 cycles Rudder: 15 drops/cycle Spoiler: 15 drops/ cycle	NOTE 1. and NOTE 6. NOTE 1. and NOTE 6. NOTE 6. NOTE 6.
3. ACTUATORS
For Example: Landing Gear Actuator Landing Gear Door Actuator Cargo Door Actuator Lockstay Actuator			NOTE 6. NOTE 6. NOTE 6. and NOTE 7.
Static Seals	No leakage	2 drops in 10 min	NOTE 6.
Rod Seal (system pressurized)	1 drop/min	30 drops/min	NOTE 6.
Rod Seal (in operation)	1 drop/cycle	2 drops/cycle	NOTE 6.
4. CONNECTIONS
Removable pipe to pipe	No leakage	2 drops in 10 min	NOTE 2. and NOTE 6.
Permanent pipe to pipe	No leakage	No leakage	NOTE 6.
Swivel fitting	No leakage	30 drops/min	NOTE 6.
Manifold fitting	No leakage	2 drops in 10 min	NOTE 2. and NOTE 6.
Bobbins	No leakage	2 drops in 10 min	NOTE 2. and NOTE 6.
Removable pipe to fitting	No leakage	2 drops in 10 min	NOTE 2. and NOTE 6.
Sliding unions (Compensated Slide)	Slight leakage	1 drop in 10 min	NOTE 2. and NOTE 6.
5. OTHER For Example: Distributor			NOTE 6. NOTE 6.
Static Seal	No leakage	2 drops in 10 min	NOTE 6.
Dynamic Seal (system pressurized)	No leakage	1 drop/min	NOTE 6.
Hydraulic Motor Shaft Seal Slats, Flaps, Trimmable Horizontal Stabilizer (pressurized and in operation).	5 drops/min	30 drops/min	NOTE 6.
Constant Speed Motor/Generator	1 drop/min	6 drops/min	NOTE 6.
Alternate Brake System			NOTE 3. and NOTE 6.
Brake Unit (at rest)	No leakage	No leakage	NOTE 6.
Brake Unit (park brake applied)	1 drop/min	2 drops/min	NOTE 5. and NOTE 6.
Ground Leakage Measurement Manifold
(at rest)	2 drops/day	4 drops/day	NOTE 6.
(system pressurized)	1 drop in 5 cycles	2 drops in 5 cycles	NOTE 6.
(after pressurization and operation)	1 drop in 15 min	2 drops in 15 min	NOTE 6.
Hand Pumps (Cargo Doors, RSVR Filling)	5 drops/min	30 drops/min	NOTE 6.
Priority Valves	No leakage	2 drops in 10 min	NOTE 6.
Manual Selector Valve	2 drops per 100 Operations	2 drops/10 min	NOTE 6.
Hydraulic-Accumulator nitrogen charging-circuits	No leakage	No leakage	NOTE 6.

NOTE: 1. For the elevator and the aileron servo-controls, two leaks of more than the normal operation limit are not permitted on the same flight surface.

NOTE: 2. It is mandatory that the connection is tight and the correct torque value is applied.

NOTE: 3. It is mandatory that no components or connections in the alternate brake system (such as the safety valves, manifold, etc.) have leaks which are more than 2 drops per 10 minutes. The total leak rate from all components and all connections, which are part of the alternate brake system, must not be more than 10 drops per minute.

NOTE: 4. Obey the leakage limits for the Yaw Damper Servo-Actuators:

If the leakage rate is less than 4 drops per minute, no more steps are necessary
If the leakage rate is between 4 and 14 drops per minute, replace the yaw damper servo-actuator(s) before the subsequent 750 flight hours (Ref. AMM TASK 27-26-51-000-001) and (Ref. AMM TASK 27-26-51-400-001)
If the leakage rate is between 15 and 30 drops per minute, replace the yaw damper servo-actuator(s) before the subsequent 100 flight hours (Ref. AMM TASK 27-26-51-000-001) and (Ref. AMM TASK 27-26-51-400-001)
If the leakage rate is more than 30 drops per minute, replace the yaw damper servo-actuator(s) immediately (Ref. AMM TASK 27-26-51-000-001) and (Ref. AMM TASK 27-26-51-400-001)
Do the visual inspection of the yaw damper servo-actuators with the part number SC4700-3 (Ref. AMM TASK 27-26-51-200-001).

NOTE: 5. A leak rate of 10 drops per minute is permitted, if the temperature is less than -40 deg.C (-40.00 deg.F).

NOTE: 6. If one or more components have an external leak rate that is more than the normal operation limit, you can dispatch the aircraft if:

The leak rate of the component(s) is less than the dispatch limit
Only one hydraulic system has component(s) with a leak rate that is more than the normal operation limit
For a given hydraulic system, the leakage is less than the dispatch limit
The fluid level in the hydraulic reservoirs is correct.

It is necessary to do the above checks again before each flight.

NOTE: 7. The limit of 2 drops in 10 min is for the time of the pressurization and operation of the Cargo Door.

(3) If no external hydraulic leak is found, it is possible that the leak is in the fuel tank(s).
(4) Do a fuel sampling for hydraulic fluid contamination (Ref. AMM TASK 12-32-28-281-802).
(5) If hydraulic fluid is found in the fuel tank(s), contact AIRBUS.
(6) System leak rate limits
(a) Usual leak rate limits:
1 The total leak rate of the Green, Yellow or Blue system must not be more than 50 drops/min.
2 If the temperature at the subsequent airport is less than -20 deg.C (-4.00 deg.F), fill the related reservoir to the maximum level shown on the reservoir:

14.0 l (3.6984 USgal) + 2.0 l (0.5283 USgal) = 16.0 l (4.2267 USgal) for the Green hydraulic system
12.0 l (3.1700 USgal) + 2.0 l (0.5283 USgal) = 14.0 l (3.6984 USgal) for the Yellow hydraulic system
6.0 l (1.5850 USgal) + 1.0 l (0.2642 USgal) = 7.0 l (1.8492 USgal) for the Blue hydraulic system.

3 Make sure that the drops of hydraulic fluid do not fall on electrical equipment.
(b) Dispatch leak rate limits with a system leak rate of between 50 and 100 drops/min.
Aircraft dispatch is permitted if all of these rules are obeyed:
1 The reservoir of the related system is full:

14.5 l (3.8305 USgal) for the Green hydraulic system
12.5 l (3.3021 USgal) for the Yellow hydraulic system
6.5 l (1.7171 USgal) for the Blue hydraulic system.

2 The component leak rate is less than the dispatch limit as given in the table above.
3 One hydraulic system only has component leaks of more than 50 drops/min.
4 The drops of hydraulic fluid do not fall on electrical equipment.
5 The rules 1_ thru 4_ above, are obeyed before each flight.
(c) The total leak rate of the Green, the Blue or the Yellow system must not be more than 100 drops/min.
(7) If there is leakage from the Hydraulic-Accumulator nitrogen charging-circuit:
(a) If it is possible to stop the leaks, pressurize the accumulator (Ref. AMM TASK 12-14-29-614-001).
(b) If it is not possible to stop the leaks, replace the accumulator, pressure gage, charging valve or manifold as necessary:

Green hydraulic system (Ref. AMM TASK 29-11-42-000-001) and (Ref. AMM TASK 29-11-42-400-001) and/or (Ref. AMM TASK 29-11-21-000-001) and (Ref. AMM TASK 29-11-21-400-001).
Blue hydraulic system (Ref. AMM TASK 29-12-42-000-001) and (Ref. AMM TASK 29-12-42-400-001) and/or (Ref. AMM TASK 29-12-21-000-001) and (Ref. AMM TASK 29-12-21-400-001).
Yellow hydraulic system (Ref. AMM TASK 29-13-42-000-001) and (Ref. AMM TASK 29-13-42-400-001) and/or (Ref. AMM TASK 29-13-21-000-001) and (Ref. AMM TASK 29-13-21-400-001).
Yellow pressure brake-accumulator (Ref. AMM TASK 32-44-11-000-001) and (Ref. AMM TASK 32-44-11-400-001) and/or (Ref. AMM TASK 32-44-14-000-001) and (Ref. AMM TASK 32-44-14-400-001) and/or (Ref. AMM TASK 32-44-13-000-001) and (Ref. AMM TASK 32-44-13-400-001) and/or (Ref. AMM TASK 32-44-17-000-001) and (Ref. AMM TASK 32-44-17-400-001).

Subtask 29-00-00-864-050-A

C. Depressurization of the Hydraulic System
(1) Depressurize the necessary hydraulic system(s):

For the Green hydraulic system (Ref. AMM TASK 29-10-00-864-001) or (Ref. AMM TASK 29-23-00-864-001)
For the Yellow hydraulic system (Ref. AMM TASK 29-10-00-864-002)
For the Blue hydraulic system (Ref. AMM TASK 29-10-00-864-003).

(2) If the quantity of the leak from a component is more than the limits, repair or replace the component as necessary.

5. Close-up
Subtask 29-00-00-942-050-A

A. Remove the piece of cloth or paper from below the component(s) which had the leaks.

Subtask 29-00-00-410-050-A

B. Close Access
(1) Connect the seal drain pipes which you disconnected before.
(2) Clean the area of leakage (Ref. AMM TASK 51-78-00-615-002).
(3) Make sure that the work area is clean and clear of tools and other items.
(4) Close the access panels/doors which you opened.

[Rev.10 from 2021] 2026.04.01 00:13:26 UTC