Which Pumps supply Normal Hydraulic pressure to the Hydraulic System?
The 3 A Pumps ( two EDPs 1A & 2A + one ACMP 3A) which operate continuously.
How many ACMP Pumps may be operating on the ground while on APU or External Power?
- 2 ACMP (a Single Generator can handle a maximum of 2 pumps).
Note: Above 43,000 ft only 1 ACMP.
Which Hydraulic Systems are powered by the EDP?
Systems 1 & 2 by EDP 1A & 2A.
What is the Nominal Hydraulic System Pressure?
Nominal Hydraulic System Pressure: 3,000 psi.
How are the Primary Flight Controls controlled and actuated?
- Electronically by the FBW Fly-by-Wire System;
- Hydraulically actuated by PCUs (Power Control Units).
Which Hydraulic Systems power the Aileron PCUs?
- Left Aileron: Hydraulic System 1 and 3;
- Right Aileron: Hydraulic System 2 & 3.
Which Hydraulic Systems power the Elevator PCUs?
- Left Elevator: Hydraulic Systems 1 & 3;
- Right Elevator: Hydraulic Systems 2 & 3.
Which Hydraulic Systems power the Rudder PCUs?
All. Hydraulic Systems 1, 2 & 3.
Which Hydraulic Systems operate the Landing Gear?
- Hydraulic System 2: Nose Landing Gear + NWS.
- Hydraulic System 3: Main Landing Gear Retraction, Assistance for Extension.
What Type of Hydraulic fluid is used in the Airplane?
Skydrol (low density fluid), Phosphate Ester Type IV or V.
How is the Hydraulic Fluid cooled?
2 Fuel/Oil Heat Exchangers located in the Fuel Tanks.
How is the Hydraulic Reservoir Quantities accurately checked before Engine Start?
-Turn ON the “B”(ACMP 1B & 3B) and PTU Pumps to pressurize the System;
- Use the Hydraulic Synoptic page to read the value;
- Note: The quantity indications are only accurate when the System is Pressurized.
What should the Brake Accumulators pre-charge pressure be when the Hydraulic System is Depressurized?
650psi +/- 100psi.
What are the Electrically Driven Hydraulic Pumps and their associated electrical power source?
- 1B & 3A = AC BUS 2
- 3B & PTU = AC BUS 1
When in AUTO, when will the ACMP 1B operate?
- When the Airplane is in the Takeoff or Approach phase;
- EDP 1A has failed or LH Engine is Not running in flight;
- The PTU valve is enabled (EDP 2A has failed or RH Engine is Not running).
When in AUTO, when will the PTU operate?
- When the airplane is in the Takeoff or Approach phase;
- EDP 2A has failed or RH engine is not running in flight;
- On the ground with only the LH Engine running and Parking Brake released.
When in AUTO, when will the ACMP 3B operate?
- When the airplane is in the Takeoff or Approach phase;
- ACMP 3A has failed.
How can the EDP HYD SOVs be closed?
- The L (R) HYD SOV guarded PBA on the Hydraulic Panel is pressed;
- The L (R) ENG FIRE guarded PBA on the FIRE Panel is pressed;
- Temperature sensors on the HYD Systems 1 & 2 reservoirs detect Excessive Fluid Temperature 125°C.
- Note: 104°C = Amber “HYD 1 (2) HI TEMP”
125°C = HYD SOV closes “L (R) HYD SOV CLOSED”
143°C = Thermal fuse ruptures (reservoir discharges fluid overboard).
Which Hydraulic Pumps are available/operating during Single Generator operations in flight?
- Operating EDP (Engine Hydraulic Pumps);
- Maximum of 2 ACMPs can be powered by a Single Generator;
- Except for APU above 43,000 ft where only 1 ACMP can be powered by the APU Generator.
Which Hydraulic System can be powered by the RAT (Ram Air Turbine)?
Hydraulic System 3.
What’s the RAT/Bootstrap Accumulator pre-charge pressure when the Hydraulic System is Depressurized?
1,100 psi +/- 100psi.
What’s the Fwd and Aft Accumulator pre-charge pressure when the Hydraulic System is Depressurized?
- 1,300psi +/- 100psi.
Note: The Fwd and Aft accumulators provide momentary Hyd pressure while the RAT is in transit.
All 3 Accumulators are on Hydraulic System 3.
