Message Name:

HYDRAULIC SYSTEM 3 (EXTERNAL LEAKAGE)

There is external fluid leakage from the Hydraulic System 3 Pump(s).

• AC Motor Pump (ACMP) 3A (B53)
• AC Motor Pump (ACMP) 3B (B54)

Advisory Wire/Service Bulletin: None

Forum Articles/Infoservice/Newsletter: None

1. Check if the ACMP 3A and/or 3B has static or dynamic leakage.

   1. For dynamic leakage of ACMP 3A and/or 3B, go to step 9.
   2. For static leakage of ACMP 3A and/or 3B, continue with next step.

2. For static leakage of ACMP 3A and/or 3B, put a container below the ACMP (3A and/or 3B) that has leakage.
3. Pressurize the hydraulic system 3 with the applicable ACMP.
   NOTE: If the drops are not directly in view or with 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. Operate the applicable ACMP(s) for 10 minutes.
5. Record the time from the first drop of fluid to the second drop 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.
6. Continue to count the hydraulic fluid drops and compare the recorded count with the static leakage in the table that follows:

   HYDRAULIC SYSTEM 3 ACMP STATIC LEAKAGE RATES
   COMPONENTS	TYPE OF SEAL	MAXIMUM LEAKAGE PERMITTED
   AC-Motor-Driven Pump	Shaft Seal	5 drops/1 minute
   	Housing (mating surfaces)	No Leakage

   NOTE: 20 drops=1 ml. Measure the leakage when the hydraulic system is at the correct temperature of operation.

7. Release the hydraulic pressure from the hydraulic system 3.
8. Clean the hydraulic fluid leakage from the area and do close out.
9. For dynamic leakage of ACMP 3A and/or 3B, put a container below the ACMP (3A and/or 3B) that has leakage.
10. Pressurize the hydraulic system 3 (AMM TASK 29-10-00-862-803).
    NOTE: If the drops are not directly in view or with 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

11. Operate the applicable ACMP(s) for approximately 10 minutes.
12. Operate the applicable flight controls through 25 cycles.
13. Record the time from the first drop of fluid to the second drop 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.
14. Continue to count the hydraulic fluid drops and compare the recorded count with the dynamic leakage in the table that follows:

    HYDRAULIC SYSTEM 3 ACMP DYNAMIC LEAKAGE RATES
    COMPONENTS	TYPE OF SEAL	MAXIMUM LEAKAGE PERMITTED
    AC-Motor-Driven Pump	Shaft Seal	10 drops/1 minute
    	Housing (mating surfaces)	No Leakage

    NOTE: 20 drops=1 ml. Measure the leakage when the hydraulic system is at the correct temperature of operation.

15. Release the hydraulic pressure from the hydraulic system 3.
16. Clean the hydraulic fluid leakage from the area.
17. Do close out.