13 - Hydraulics Flashcards
- What are the hydraulic systems of the 737?
- System A
- System B
- Standby
- How are hydraulic reservoirs pressurized?
System A and B are pressurized by bleed air.
Standby system is pressurized through system B through a fill line
- How are hydraulic systems quantity and pressure indications indicated on the MDS?
By selecting SYS on the MFD
- What does an RF on the HYDRAULIC indicator indicate and when is it valid?
- The reservoir is below 76%
- Only valid on the ground with both engines shut down, or
- After landing during taxi in with the flaps UP
- How does flap operation affect hydraulic fluid quantity indications?
Extension of the leading edge devices may result in up to 20% drop in indicated quantity
- What is the normal pressure of hydraulic systems A & B?
3,000 psi +/-200
- When does the STANDBY HYD LOW QUANTITY light illuminate?
When the standby hydraulic system has less than 50% quantity in the reservoir
- Which precaution(s) should be taken when turning on the electric hydraulic pumps?
- Turn on the EMDPs one at a time to avoid an amperage surge
- Ensure there is at least 1,675lbs of fuel in the respective main tank
- What does moving a FLT CONTROL switch to STBY RUD do?
• activates the standby electric motor-driven pump
• shuts off the related hydraulic system pressure to ailerons, elevators, and rudder by closing the flight control shutoff valve
• opens the standby rudder shutoff valve
• allows the standby system to power the rudder and thrust reversers
• deactivates the related FLT CONTROL LOW PRESSURE light when the standby
rudder shutoff valve opens
• arms the STANDBY HYD LOW PRESSURE light
• illuminates the STBY RUD ON light and the FLT CONT System Annunciator and
MASTER CAUTION lights
- What causes the automatic operation of the standby hydraulic system?
When one of the following conditions exist with the FLT CONTROL switches positioned ON and the loss of system A and/or B:
• Flaps extended, airborne
• Flaps extended, wheel speed greater than 60 kts
- What does automatic operation of the standby hydraulic system activate?
• activates the standby electric motor-driven pump
• opens the standby rudder shutoff valve
• allows the standby system to power the rudder and thrust reversers
• illuminates the STBY RUD ON light and the FLT CONTROL System Annunciator and
MASTER CAUTION lights
- What is the purpose of the PTU?
To provide hydraulic system B fluid at a flow rate and pressure for normal rates of operation of the autoslats and leading edge devices
- What fluid percentage does the standpipe in the system A reservoir preserve in the event of a leak?
20%
- What fluid percentage does the standpipe in the system B reservoir preserve in the event of a leak?
Approximately 0%
- With 0% indicated on the system B quantity indicator, can the PTU still operate?
Yes