Message Name:

HYDRAULIC SYSTEMS 1 (EXTERNAL LEAKAGE)

There is external fluid leakage from the Hydraulic Pump 1 or related components.

• AC Motor Pump (ACMP) 1B (B51)
• Engine Driven Pump (EDP)

Advisory Wire/Service Bulletin:

• AW700-29-0494 - No.1 Hydraulic Pressure Tube - Aft Equipment Compartment

Forum Articles/Infoservice/Newsletter: None

1. Check if the ACMP 1B and flight control component has static or dynamic leakage.

   1. If there is dynamic leakage for flight control component, go to step 25.
   2. If there is static leakage for flight control component, go to step 19.
   3. If there is dynamic leakage for ACMP 1B, go to step 10.
   4. If there is static leakage for ACMP 1B, continue with next step.

2. For static leakage of ACMP 1B, put a container below the hydraulic system 1 pump with the static leakage.
3. For static leakage of an ACMP, pressurize the hydraulic system 1.
   NOTE: If you cannot see the drops directly or in a mirror, count the drops as follows:

   • Put one drop of hydraulic fluid on the container and measure its area
   • Clean the drop from the container
   • Put the clean container below the leak
   • Measure the area on the container made by the drops and compare it with the area of the one drop

4. For static leakage of an EDP, start the aircraft engine 1.
   NOTE: The hydraulic system 1 EDP (1A) is installed on the engine 1.
5. Operate the hydraulic pump 1 for ten minutes.
6. Record the time from the first drop of fluid to the subsequent drops of fluid.
   NOTE: If there is more than one source of the hydraulic fluid leakage, you must count the drops from each source. Make sure you count the drops from one source at a time.
7. Compare the count with the static leakage rates as follows:

   HYDRAULIC PUMPS 1 - STATIC LEAKAGE RATES
   Components	Type of Seal	Maximum Leakage Permitted
   Engine-Driven Pump	Shaft Seal	1 drop/10 minutes
   	Housing	No Leakage
   AC-Motor-Driven Pump	Shaft Seal	5 drops/1 minute
   	Housing (mating surfaces)	No Leakage

   NOTE: 20 drops=1 ml. The leakage rates given are at a component temperature of 100 °F (37.8 °C).

8. Release the hydraulic pressure in the hydraulic system 1. In the flight compartment, on the HYDRAULIC control panel, set the applicable ACMP switch to OFF. Remove the electrical power from the aircraft, if applicable. To turn off the EDP(s), stop the aircraft engine(s) 1.
   CAUTION: USE ONLY APPROVED CLEANING AGENTS WHEN YOU CLEAN THE HYDRAULIC FLUID LEAKAGE. SOME CLEANING AGENTS CAN CAUSE DAMAGE TO HYDRAULIC PARTS.
9. Clean the hydraulic fluid leakage from the area and do close out.
10. For dynamic leakage of ACMP 1B, put a container below the hydraulic system 1 pump with the dynamic leakage.
11. For an ACMP, pressurize the hydraulic system 1.
12. For an EDP, start the aircraft engine(s) 1.
    NOTE: The hydraulic system 1 EDP (1A) is installed on the engine 1.
13. Operate the applicable hydraulic pump(s) for approximately 10 minutes.
14. Operate the applicable flight controls through 25 cycles.
    For Hydraulic system 1:

    • Aileron LH or
    • Elevator LH

15. Record the time from the first drop of fluid to the subsequent drops of fluid.
    NOTE: If there is more than one source of the hydraulic fluid leakage, you must count the drops from each source. Make sure you count the drops from one source at a time.
16. Compare the count with the dynamic leakage rates as follows:

    HYDRAULIC PUMPS 1 - DYNAMIC LEAKAGE RATES
    Components	Type of Seal	Maximum Leakage Permitted
    Engine-Driven Pump	Shaft Seal	1 drop/2 minutes
    	Housing	No Leakage
    AC-Motor-Driven Pump	Shaft Seal	10 drops/1 minute
    	Housing (mating surfaces)	No Leakage

    NOTE: 20 drops=1 ml. The leakage rates given are at a component temperature of 100 °F (37.8 °C).

17. Release the hydraulic pressure in the hydraulic system 1. In the flight compartment, on the HYDRAULIC control panel, set the applicable ACMP switch to OFF. Remove the electrical power from the aircraft, if applicable. To turn off the EDP, stop the aircraft engine 1.
    NOTE: If you cannot see the drops directly or in a mirror, count the drops as follows:

    • Put one drop of hydraulic fluid on the container and measure its area
    • Clean the drop from the container
    • Put the clean container below the leak
    • Measure the area on the container made by the drops and compare it with the area of the one drop

18. Clean the hydraulic fluid leakage from the area and do close out.
19. For static leakage of flight control component, put a container below the leakage and pressurize the hydraulic systems 1.
20. Operate the applicable hydraulic pumps for approximately 10 minutes.
21. With no movement of the applicable flight control, record the time from the first drop of fluid to the subsequent drops of fluid.
    NOTE: If there is more than one source of the hydraulic fluid leakage, you must count the drops from each source. Make sure you count the drops from one source at a time.
22. Compare the count with the static leakage rates as follows:

    STATIC LEAKAGE RATE
    Components	Type of Seal	Maximum Leakage Permitted
    Actuating Cylinder	Rod Seal	No Leakage
    Servo Actuator	Rod Seal	No Leakage

    NOTE: 20 drops=1 ml. Measure the leakage when the hydraulic system is at the correct temperature for operation. The leakage rates given are at a component temperature of 100 °F (37.8 °C).

23. Release the hydraulic pressure in the hydraulic system 1.
    NOTE: If you cannot see the drops directly or in a mirror, count the drops as follows:

    • Put one drop of hydraulic fluid on the container and measure its area
    • Clean the drop from the container
    • Put the clean container below the leak
    • Measure the area on the container made by the drops and compare it with the area of the one drop

24. Clean the hydraulic fluid leakage from the area and do close out.
25. For dynamic leakage of flight control component, put a container below the leakage and pressurize the hydraulic system 1.
26. Operate the applicable flight control components through 25 cycles and then stop.
27. During movement of the applicable flight control, record the time from the first drop of fluid to the subsequent drops of fluid.
    NOTE: If there is more than one source of the hydraulic fluid leakage, you must count the drops from each source. Make sure you count the drops from one source at a time.
28. Compare the count with the dynamic leakage rates as follows:

    DYNAMIC LEAKAGE RATE
    Components	Type of Seal	Maximum Leakage Permitted
    Actuating Cylinder	Rod Seal	1 drop/25 cycles
    Servo Actuator	Rod Seal	1 drop/25 cycles

    NOTE: 20 drops=1 ml. Measure the leakage when the hydraulic system is at the correct temperature for operation. The leakage rates given are at a component temperature of 100 °F (37.8 °C).

29. Release the hydraulic pressure in the hydraulic system 1.
    NOTE: If you cannot see the drops directly or in a mirror, count the drops as follows:

    • Put one drop of hydraulic fluid on the container and measure its area
    • Clean the drop from the container
    • Put the clean container below the leak
    • Measure the area on the container made by the drops and compare it with the area of the one drop

30. Clean the hydraulic fluid leakage from the area.
31. Remove the electrical power from the aircraft. Make sure there is no hydraulic fluid leakage in the aft equipment compartment for the hydraulic system and its components.
32. Do close out.