AH-64(E) Hydraulic System Flashcards
The AH-64(E) is comprised of __ independent hydraulic systems.
2
Only the ________ sides of the flight control servoactuators have an electrohydraulic servovalve that allow the Flight Management Computer (FMC) and Back-Up Control System (BUCS) to affect the flight controls.
Primary
In the event both hydraulic systems fail, the Utility __________ directs pressurized hydraulic fluid to the flight control servoactuators, allowing for an emergency landing
Accumulator
Failure of the Primary Hydraulic System results in the loss of the ____ and the ____ inputs.
Flight Management Computer (FMC)
Backup Control System (BUCS)
During normal operation, _____ air enters the Primary reservoir through the air inlet check valve. The pressurized air acts upon the reservoir piston, creating low-pressure hydraulic fluid and helps prevent pump cavitation.
IPAS
The low-pressure hydraulic fluid is drawn from the Primary manifold by the Primary hydraulic pump, pressurized to ____ psi, and then sent back to the Primary manifold assembly.
3,000 psi
The Utility Hydraulic System provides hydraulic pressure to the following components:
R
A
A
A
T
E
E
S
- Rotor Brake
2.APU Starter - AWS Azimuth/Elevation
- Ammo Drive Motor
- Tail Wheel Lock Actuator
- Emergency Hydraulics
- External Stores Elevation Actuator
- Servos (Utility Side)
The AUXILIARY ISOLATION VALVE automatically eliminates fluid pressure to the following auxiliary components during an emergency (loss of system pump pressure) or (low fluid level conditions) once the low level valve has been closed in the reservoir:
1. A______________
2. A______________
3. P______________
- AWS Elevation Actuator and Azimuth Drive Motor
- Ammunition Carrier Drive Motor
- Pylons
The LOW-LEVEL switch provides a signal to the MP when the oil level has dropped to a minimum operating level. It also provides a 28 Vdc signal to actuate the emergency hydraulic shutoff valve, shutting off fluid flow to the ______________________________ and the Utility side of the ________________ servo.
- Tail wheel unlock actuator
- Tail Rotor
The accumulator ______________________________ allows Utility System pump pressure to repressurize the accumulator after an APU start.
Isolation Inlet Check Valve
After shutdown of the aircraft or loss of Utility pump pressure, the _____________ isolation valve maintains isolation of accumulator fluid from the rest of the system.
Accumulator
When a crewmember activates the _______________ pushbutton from OFF to ON, pressurized hydraulic fluid from the _____________ is allowed to pass through the accumulator isolation valve to the flight control servoactuators.
EMERG HYD
Accumulator
When the NR is below 50 percent, the pilot’s Rotor Brake Control switch may be set to the ___ position. Accumulator fluid pressure will open the brake valve, and fluid is routed through the brake-metering valve, reducing its pressure to 337 ±25 psi. It then enters the rotor brake actuator and slows down the rotation of the main rotor.
BRK
Placing the pilot’s Rotor Brake Control switch in the LOCK position causes the two brake-hold check valves to close. This eliminates the pressure-reducing capability of the brake-metering valve and allows full accumulator pressure (____ psi) to flow through the brake and metering valves to the rotor brake actuator.
3,000 psi
If leakage in the Utility System activates the Utility manifold’s low-level switch, a 28 Vdc electrical signal closes the emergency hydraulic shutoff valve. This conserves the remaining fluid for use by the ____ _____ flight control servoactuators.
Main Rotor
