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.
The operation of the standby hydraulic system____ by a leak in hydraulic system B
is not affected
Which system can power all flight controls with no decrease in aircraft controllability?
Either A or B hydraulic system
What is the max tire ground speed?
195 Knots
Hydraulic power for retraction, extension, and nose wheel steering is normally supplied by which hydraulic system?
Hydraulic System A
The alternate brake system is powered by ______ and the normal brakes system is powered by_____
Hydraulic system A
Hydraulic system B
Antiskid protection is provided by which brake system?
on both brake system (normal and alternate)
The ____ stop rotation of the main gear wheels during landing gear retraction.
brakes automatically
The nose wheels retract forward into the wheel well and nose wheel rotation is stopped by ___ during landing gear retraction
snubbers
What happens when moving the LANDING GEAR lever to the OFF position?
Hydraulic pressure from the landing gear system is removed
An illuminated red landing gear indicator light indicates the ____ or the related landing gear is in disagreement with LANDING GEAR lever position ( in transit or unsafe)
Landing gear not down and locked (with either or both forward thrust levers retarded to idle and below 800’ agl. )
What does an extinguished green landing gear indicator light indicate?
The gear is not down and locked
When the LANDING GEAR lever is moved to DN, hydraulic system pressure is used to release the uplocks. How is the landing gear extended.
Hydraulic Pressure
Gravity
Air Loads
If ___ green landing gear indicator lights (center panel and or overhead panel) for each gear is/are illuminated, the landing gear is down and locked.
AT LEAST one
The landing gear transfer unit allows hydraulic system B to supply the volume of hydraulic fluid required to raise the landing gear at the normal rate when airborne, LANDING GEAR lever is positioned UP, ____ and either main landing gear is not up and locked.
No 1 engine RPM drops below a limit value
What effect on landing gear retraction does opening the Manual Extension Access Door have?
disables it
With the landing gear lever ____, manual landing gear extension is possible.
in any position
The 737 manual gear release on the flight deck are used to ___ that allow the gear to ___ to the down and locked position.
Release uplocks
Free-Fall
Nose wheel steering will be available____
When the nose gear is in the down position and compressed by the weight of the airplane
Pushing the rudder pedals down allows for nose wheel turning up to ____ degrees in both directions
7 degrees
____ allows the aircraft to push back or be towed without depressing hydraulic system A.
A lockout pin
Switching the Nose Wheel Steering switch to ALT, allows ____ to provide power for nosewheel steering.
Hydraulic system B
If the normal and alternate brake system pressure is lost, trapped hydraulic pressure in the brake accumulator can still provide ____ or a parking brake application.
several braking applications
Skid, locked wheel, touchdown and hydroplane protection will be available ____
with the normal and alternate braking system
The 737 Parking Brake can be set with
A or B hydraulic system or the accumulator if A and B are not pressurized
What is the normal hydraulic brake pressure as indicated on the brake accumulator
3000 PSI - that’s the green part
Placing the AUTO BRAKE select switch to 1,2,3 or MAX selects the desired ____ for touchdown
Deceleration rate
With the AUTO BRAKE select switch in the RTO position, maximum brake pressure is automatically applied when the thrust levers are retarded to IDle at or above ____ knots?
90 knots
On a dry runway, the max autobrake deceleration rate in the landing mode is ____ that produced by full pedal braking.
less than
After the autobraking has started decelerating, any of the following pilot actions disarm the system immediately and will illuminate the AUTO BRAKE DISARM light
Moving Speed Brake Lever Full Forward
Applying Manual Brakes
Advancing the forward thrust levers- except during the first 3 seconds after touchdown
The aircraft has ___ hydraulic systems!
3
Normal operating pressure for each hydraulic system is _____ psi
3000
On the ground with both engines shutdown, a REFILL indciation illuminated white RF next to the hydraulic quantity indicates ____
hydraulic quantity below 76%
