Flushing the hydraulic system

Preliminary requirements

Support equipment

Name	Identification/References	Quantity	Remark
Extraction syringe	Commercial	1	Syringe 7075 from CTA Manufacturing Corp or equivalent.
Container	Commercial	1

Spares

Name	Identification/References	Quantity

Procedure

It is normal for the reservoir to fill and overflow at the inlet when using the HPU. The time to fill is dependent on the length

1. Install the hydraulic power unit (HPU).

2. Set hydraulic pressure on cart to 400 psi and flow rate at 2.0 GPM +/- 0.5 GPM and cycle the actuators to full stroke for 5 minutes.

3. Fully drain the hydraulic fluid from the HRFM.

4. Fill the HRFM with Hydraulic fluid.

5. Repeat step 3.

6. Disconnect the pressure line (to HRFM) at the hydraulic pump, pressure filter assembly, and check valve and allow draining.

7. Replace the pressure filter element.

8. Replace the HRFM filter element.

9. Reconnect the suction (M206-20H102-041) and pressure lines (M206-20H101-041) to the pump.

10. Fill the HRFM reservoir to full.

11. Turn the rotor by hand to remove air.

12. Verify HRFM fluid level.

13. Do a 15-minute ground run of the helicopter.

14. Take fluid samples from the HRFM reservoir and analyze for particle contamination. Contamination level shall be less than the levels defined in Table 1.

Table 1. Cleanliness Requirements for Synthetic Hydrocarbon Based Hydraulic Fluid Systems

Particle Size (microns)	Number of Particles (in 100ml)
5-10	87,000
11-25	21,400
26-50	1,510
51-100	225
101 and greater	21

14. If contamination level does not meet levels defined in Table 1, do the steps that follow:

    1. Replace the hydraulic pump.

    2. Repeat steps 1 through 13.

Requirements after job completion

Required Conditions

Action/Condition	Procedure/Data
Check fluid level of hydraulic system	Checking the fluid level of the hydraulic system