CRJ 200 Hydraulic Sample Questions

• Specifically what does hydraulic system 2 power?

  Outboard brakes, inboard ground spoilers, main landing gear auxiliary actuators, flight spoilers, right aileron, right spoileron, rudder and elevator.

• What is the normal PSI of the hydraulic systems?

  3000 PSI.

• What is the only difference between hydraulic system 1 and 2 other than what they operate?

  The reservoir capacities are different; system 2 is larger due to powering more equipment.

• When do system 1A and 2A main hydraulic pumps operate?

  Any time the respective engine is operating.

• What three things determine when the backup B pumps for system 1 and 2 will operate?

  1. Cross-side engine-driven generator output. 2. Flap position. 3. Hydraulic switch position. If you have an engine failure, the opposite side hydraulic B pump will be inoperative, even if the switch is put in the ON position.

• Explain the AUTO switch position of hydraulic system 1 and 2.

  Hydraulic pumps 1B and 2B will operate when they are powered, the flaps are not at zero, and the generator on the opposite side engine is operating.

• Will hydraulic 1B or 2B automatically start after an engine failure or hydraulic pump 1A or 2A failure?

  No, the 1B or 2B hydraulic switch must be selected to ON.

• Explain the ON position of system 1 and 2.

  This is the manual mode to operate hydraulic system 1 and 2 pumps. It will turn pumps 1B and 2B on.

• During flight, if you place hydraulic system 1B or 2B switch to ON, will the pumps operate?

  The pump will operate if the respective bus is powered and the generator on the opposite side engine is operating.

• If you select the 1B or 2B hydraulic switch to ON with the aircraft on the ground and the engines not operating, will the pumps operate?

  Yes, a circuit will allow the pumps to operate on the ground with the engine-driven generators not operating.

• How are hydraulic systems 1 and 2 cooled?

  Because pumps 1A and 2A are within the engine nacelles and generate a lot of heat, the fluid needs to be cooled. The fluid is cooled by a hydraulic oil heat exchanger that is located in the aft equipment bay. The air used by the heat exchanger for cooling is drawn in through the ram air scoop. The air is exhausted out the exit point on each side of the aft part of the fuselage and has a wire screen over the exhaust area. While on the ground an electric fan inside the heat exchanger draws the air from the ram air scoop.

• Why does hydraulic system 3A and 3B not need a cooling system?

  They are not near a heat source. The lines also run through the fuel tanks.