United 737 Hydraulics Flashcards
The operation of the standby hydraulic system is _____ by a leak in hydraulic system B
not affected
What is the purpose of the PTU?
To supply the additional volume of hydraulic fluid needed to operate the autoslats or the leading edge flaps and slats at a normal rate when system B engine driven pump volume is lost
What is the purpose of the landing gear transfer unit?
To raise the landing gear at the normal rate when system A engine driven pump volume is lost
The landing gear transfer unit operates when airborne, ____ and the No. 1 engine RPM drops below a limit value.
The landing gear is positioned up and either main landing gear is not up and locked
The standby system uses a single electric motor driven pump and ____
can be activated manually or automatically
The standby hydraulic system powers the thrust reversers, ___ and rudder
leading edge flaps and slats (extend only) and the standby yaw damper
Automatic operation of the standby hydraulic pump is initiated when____ and loss of hydraulic system A or B.
flaps are extended; and airborne, or wheel speed greater than 60 knots
Positioning either FLT CONTROL switch to STBY RUD, ____ , closes the related flight control shutoff valve; deactivates the related flight control LOW PRESSURE light; allows the standby system to power the rudder and thrust reversers.
ALL ANSWERS ARE CORRECT
____ when there is a leak in the standby hydraulic system
The LOW QUANTITY light illuminates and the system B reservoir fluid decreases to approximately 72%
What is indicated by an amber illuminated Electric Hydraulic Pump OVERHEAT light?
- The hydraulic fluid used to cool and lubricate the corresponding electric motor driven pump has overheated.
- The pump itself has overheated.
The respective engine-driven hydraulic pump LOW PRESSURE light is ____ when pulling the Engine 1 Fire Warning Switch
deactivated
An illuminated amber Flight Control LOW PRESSURE light indicates low hydraulic system A or B pressure to which flight controls?
Aileron and elevator
Rudder
An illuminated amber standby hydraulic LOW QUANTITY light is ___ and indicates low quantity in the standby hydraulic reservoir.
Always armed
An illuminated amber standby hydraulic LOW PRESSURE light is ___ and indicates low output pressure.
Armed only when the standby hydraulic pump operation has been selected or automatic standby pump operation is activated
When positioning the ENG 1 hydraulic pump switch to OFF, the pump ____ to rotate and fluid flow is isolated from he system component.
continues
After an engine fire warning switch is pulled, the hydraulic fluid flow to the related engine-driven pump is shut off and ___
its LOW PRESSURE light is deactivated
____ is the minimum fuel for ground operation of electric hydraulic pumps in the related main tank
1675
What happens if a leak develops in the A system hydraulic ENGINE driven pump or its related lines?
A standpipe in the reservoir prevents a total system fluid loss
What happens if a leak develops in the A system hydraulic ELECTRIC motor driven pump or its related lines?
The quantity in the reservoir steadily decreases to zero and all system pressure is lost
What happens if a leak develops in either pump, line or component of System B?
The quantity in the reservoir steadily decreases to approx. zero and system B pressure is lost however the power transfer unit is still operational.