Hydraulics Flashcards
How are the Main #1 and #2 Hydraulic Pumps powered?
An Engine driven Pump (EDP) for each system, via the Reduction Gearbox
What is the function of the Priority Valve in Hyd 1 system?
Stops flow if the system pressure falls below 2100 psi, giving priority to the Elevators and Rudder.
What would cause a #1 or #2 ENG HYD PUMP Caution to illuminate?
Pressure falls below 2000psi on #1 or #2, high temperature valve closing the Firewall Shutoff valve.
How is Hydraulic Fluid cooled?
Each system has an oil-to-fuel heat exchanger.
How is the SPU powered?
Variable Frequency AC motor-driven pump. Right 115 v AC.
What does the Green legend on the SPU Switchlight indicate when illuminated?
That the switch has been selected ON.
When would the SPU switch ON automatically?
Flaps extended, parking brake off or #1 Engine fails in flight.
What is the minimum Emergency Brake Accumulator charge pressure for dispatch?
400 psi
When would the PTU be automatically activated?
Flaps are extended and Parking Brake is off, or in the event of engine #2 failure.
How is the Hyd 3 Pump powered?
28 v DC from the Standby Battery
What would cause the #3 STBY HYD Pump Caution to illuminate in the air?
Pressure falls to 900psi (or the pump has been operating for more than 60 secs on the ground)
What would cause an ELEVATOR PRESS Caution illuminate?
All 3 Hyd. Systems are powering the Elevators.
What is the function of the Hyd 4 System
Locking the Main Gear in the down position during the Manual Landing Gear Extension.
How is the Hyd 4 System pressurised?
Hand-pump
Where is the Hyd 4 System contents displayed?
Not displayed on the MFD, contents measured by a dipstick in the reservoir.
