Installing the hydraulic power unit
Preliminary requirements
Required Conditions
| Action/Condition | Procedure/Data |
|---|---|
Remove the right transmission fairing (432BR). | |
Remove the left transmission fairing (432AL). |
Support equipment
| Name | Identification/References | Quantity | Remark |
|---|---|---|---|
Hydraulic Power Unit (HPU) | Local supply | 1 | 600 PSI (4137 kPa) operating pressure, 1.7 gallons per minute (6.44 L/min) maximum flow, 5-micron pressure filter. |
Union | AS5174W0505 | 1 | Or equivalent. |
Consumables, materials and expendables
| Name | Identification/References | Quantity |
|---|---|---|
Caps or plugs | C-428 | AR |
Safety conditions
Make sure that the Hydraulic Power Unit (HPU) is serviced only with an approved hydraulic fluid. If you do not obey this precaution, there is a risk of contamination of the hydraulic system.
Make sure that the Hydraulic Power Unit delivery pressure is less than 400 PSI (2757.9 kPa) before you apply hydraulic power to the aircraft. If you do not obey this precaution, there is a risk of damage to the hydraulic system and/or the Hydraulic Filter Reservoir Module (HRFM).
Do not apply more than 400 PSI (2757.9 kPa) to the hydraulic system or damage to the Hydraulic Reservoir Filter Module (HRFM) can occur.
If Hydraulic Power Unit pressure exceeds 800 PSI (5515.8 kPa), inspect rupture disk for leaks or damage.
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 of duration the HPU is left on. Have appropriate spill kit on hand when using the HPU.
Put the Hydraulic Power Unit (HPU) on the right side of the helicopter, near the Hydraulic Reservoir Filter Module (HRFM).
Remove the cap assembly from the tee fitting at the pressure port (FROM PUMP) of the HRFM and keep it for use when you disconnect the Hydraulic Power Unit (HPU) (Local supply) (DMC-505-A-29-00-00-00A-522A-A).
Connect the pressure hose of the Hydraulic Power Unit (HPU) to the tee fitting.
Disconnect the elbow fitting from the check valve at the return port (FROM ACT) of the HRFM.
Connect the Union (AS5174W0505) to the elbow fitting.
Connect the return hose of the Hydraulic Power Unit (HPU) to the Union (AS5174W0505).7Install Caps or plugs (C-428) on the open port of the check valve.
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