Flashcards in Hydraulics Deck (42)
Which systems use hydraulic power?
leading edge flaps/slats
trailing edge flaps
nose wheel steering
T/F: Airplane controllability is reduced with a single loss of sys A or sys B.
false. no reduction.
Where are the 3 hydraulic reservoirs?
in main wheel well.
Sys A and B incorporate a ______ that may prevent a total loss of system fluid should a leak develop.
Which system services the standby system for pressurization?
Sys B supplies.
With pumps operating, what is normal hydraulic pressure?
3000 psi to a max of 3500 psi.
What does RF mean?
Hydraulic qty is below 76%. Only accurate with aircraft on ground and engines shut down or taxi-in with flaps up.
Sys A components:
Elevator & elevator feel
flight spoilers (2 on each wing)
No 1 Thrust reverser
Normal nose wheel steering
Power Transfer Unit (PTU)
Sys B Components
Elevator & Elevator Feel
Flight Spoilers (2 on each wing)
Leading edge flaps and slats
No 2 thrust reverser
Alternate nose wheel steering
Landing gear transfer unit
Trailing Edge flaps
What types of pumps do Sys A and B have?
engine driven and electric. Engine driven pumps produce a flow rate 4x better than electric pumps.
Which generators supply power to the electric driven pumps?
Gen 1 supplies #2 elec pump
Gen 2 supplies #1 elec pump
How do the ENG hyraulic pumps work if their switches are moved off?
A blocking valve closes so fluid is isolated and the pump actually still works. Pump still rotates if engine is still on.
T/F: A minimum amount of fuel is req'd in each main tank for operation of the electric motor driven pumps
What do hydraulic LOW PRESSURE lights mean?
Low output pressure from either engine-driven or electric hydraulic pumps.
What is the purpose of the PTU?
automatically supply an additional volume of hydraulic fluid to the autoslats and leading edge flaps and slats.
When will the PTU work?
only operate when Sys B engine driven pump volume is lost.
How does the PTU work?
uses Sys A pressure to power a hydraulic motor-driven pump which then pressurizes sys B
What are the conditions for the PTU to operate?
Must be airborne
Sys B engine driven pump pressure is low
Flaps are less than 15 but not up
What is the purpose of the Landing Gear Transfer Unit
uses Sys B engine driven pump pressure to raise the gear at the normal rate when Sys A engine driven pressure is low.
Conditions for Landing Gear Transfer Unit to work
No. 1 eng at low RPM
Land gear lever is in UP position
either main gear is not up and locked.
T/F: the stby hydraulic system operates both manually and automatically
What systems are powered when the stby hydraulic system is activated?
thrust reversers, rudder, leading edge flaps and slats (for extension only); standby yaw damper
What does the electric hydraulic pump OVERHEAT light mean?
pump has overheated OR that hydraulic fluid that normally cools and lubricates pump has overheated.
Before initially applying power to the aircraft, ensure the ________ switches are off.
ELEC HYD PUMP
T/F: The ENG HYD PUMP switches are normally left ON to prolong solenoid life
If pushback is req'd w/out the use of a nose gear steering lockout pin, both Sys A pumps must be selected _____.
If the elec pump for Sys A is the only one on in flight, you may get an intermittent LOW PRESSURE light for the electric pump during __________.
heavy system demand.
What might be happening if LOW PRESSURE light flickers at high altitudes?
Foaming of the hydraulic fluid if the system is not properly pressurized.
The standby system is controlled manually through ________ or the _______
FLT CONTROL switches or ALTERNATE FLAPS master switch.