SWA B737 - Hydraulics Flashcards
(Hydraulics) How many independent Hydraulic Systems are there?
- Hydraulic System A
- Hydraulic System B
- Standby Hydraulic System
Hydraulics) How many Hydraulic Pumps do Hydraulic System A and Hydraulic System B have?
- Engine Driven Pump (EDP)
* Electric Motor Driven Pump (EMDP)
(Hydraulics) What is Normal and Max Operating Pressure of the Hydraulic Pumps?
- Normal (3000 PSI)
- Maximum (3500 PSI)
- Minimum During Preflight (2800 PSI)
(Hydraulics) How can the Standby Hydraulic Pump be activated?
- Automatically or
* Manually
Hydraulics) How do you manually activate the Standby Hydraulic Pump?
By selecting either FLT CONTROL (Guarded) Switch on the Flight Control Panel to STBY RUD
Placing the Alternate Flap switch to ARM
Hydraulics) When will the Standby Hydraulic Pump automatically turn on?
When all of the following conditions exist:
• Loss of System A or B
• Flaps Extended
• In Flight or Wheel Speed > 60 knots
• FLT CONTROL (Guarded) Switch A or B ON (Standby Pump will also activate if the PCU Force Fight Monitor (FFM) trips)
(Hydraulics) How many Hydraulic Pumps does the Standby Hydraulic System have?
• Electric Pump
(Hydraulics) What does an illuminated LOW QUANTITY light under STANDBY HYD on the Flight Control Panel indicate?
Standby Hydraulic Reservoir Level has dropped below 50% (This light is always armed)
(Hydraulics) How do you know if Hydraulic System A or B need servicing?
An RF (or Refill) will be displayed next to the Hydraulic Quantity (The RF indication is only valid on the Ground with both Engines shut down or after Landing with the Flaps retracted)
(Hydraulics) in Hydraulic System A, where is the Standpipe Protection?
In the Engine Driven Pump (would leave approximately 20% fluid in System A, however if a leak occurs in System A Electric Pump there is no Standpipe Protection and the Hydraulic Fluid Quantity would steadily decrease to Zero and all System Pressure would be lost)
(Hydraulics) In System B, where is the Standpipe Protection?
Both the Engine Driven and Electric Pump (If a leak develops in any component of System B the Quantity would indicate Zero and System B Pressure would be lost, however there would still be fluid in the reservoir - this is to provide sufficient hydraulic fluid for Power Transfer Unit (PTU) operation)
(Hydraulics) How is the Standby Hydraulic Reservoir Pressurized?
It is not directly pressurized, however since Hydraulic System B is pressurized, this exerts power on the Standby Hydraulic Fluid
(Hydraulics) Do the System A and B Engine Driven Pump switches turn the Hydraulic Pumps ON and OFF?
No - when the Engines are running the Engine Driven Pumps are also ON. The switch operates a Blocking Valve which will block the fluid if the switch is in the OFF position.
(Hydraulics) What does an illuminated LOW PRESSURE over the Hydraulic Pump Switches on the Hydraulic Panel indicate?
The Associated Output Pressure is Low (When the associated Engine Fire Warning Switch is pulled, the Hydraulic SOV will close, however you won’t get those lights because the LOW PRESSURE lights are deactivated
(Hydraulics) How is the Engine Driven Pump cooled and lubricated?
By fluid flowing through the pump (even with the Blocking Valve Energized, since it is downstream of the Pump it is still cooled and lubricated by moving Hydraulic Fluid through the Pump then back to the Reservoir)