Hydraulics Flashcards by Dave Mittman

Which systems use hydraulic power?

Flt controls
leading edge flaps/slats
trailing edge flaps
landing gear
wheel brakes
nose wheel steering
thrust reversers
autopilots

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T/F: Airplane controllability is reduced with a single loss of sys A or sys B.

false. no reduction.

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Where are the 3 hydraulic reservoirs?

in main wheel well.

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Sys A and B incorporate a ______ that may prevent a total loss of system fluid should a leak develop.

standpipe

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Which system services the standby system for pressurization?

Sys B supplies.

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With pumps operating, what is normal hydraulic pressure?

3000 psi to a max of 3500 psi.

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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.

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Sys A components:

Ailerons
Rudder
Elevator &amp; elevator feel
flight spoilers (2 on each wing)
Ground spoilers
Alt brakes
No 1 Thrust reverser
Autopilot A
Normal nose wheel steering
Landing gear
Power Transfer Unit (PTU)

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Sys B Components

Ailerons
Rudder
Elevator &amp; Elevator Feel
Flight Spoilers (2 on each wing)
Leading edge flaps and slats
Normal brakes
No 2 thrust reverser
Autopilot B
Alternate nose wheel steering
Landing gear transfer unit
Autoslats
Yaw damper
Trailing Edge flaps

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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.

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Which generators supply power to the electric driven pumps?

Gen 1 supplies #2 elec pump

Gen 2 supplies #1 elec pump

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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.

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T/F: A minimum amount of fuel is req’d in each main tank for operation of the electric motor driven pumps

True.

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What do hydraulic LOW PRESSURE lights mean?

Low output pressure from either engine-driven or electric hydraulic pumps.

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What is the purpose of the PTU?

automatically supply an additional volume of hydraulic fluid to the autoslats and leading edge flaps and slats.

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When will the PTU work?

only operate when Sys B engine driven pump volume is lost.

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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

Airborne
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

true

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

True

If pushback is req'd w/out the use of a nose gear steering lockout pin, both Sys A pumps must be selected _____.

OFF

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.

What happens when either FLT CONTROL switch is moved to the STBY RUD position?

electric motor driven pump activates. the related flt controll shutoff valve closes removing system pressure from the ailerons, elevator and rudder, The stby rudder shutoff valve opens. STBY RUD ON light illuminates.

What happens when you move the ALTERNATE FLAPS switch to ARM?

closes the trailing edge flap bypass valve arms the ALTERNATE FLAPS position switch allows the stby system to power the leading edge devices and thrust reversers

T/F: during critical phases of flight, the sby system operates automatically to compenstate for loss of sys A or B.

True

When will automatic operation of the STBY system occur?

``` Loss of Sys A or B Flaps extended Airborne or wheel speed is 60kts or greater Sys A or B FLT CONTROL switch on Main PCU Force Fight Monitor (FFM) trips ```

When is the STANDBY HYD LOW PRESSURE light armed?

stby operation has been selected manually or when the automatic standby function is active

What happens with complete loss of SYS A pressure?

both LOW PRESSURE lights come on, Sys A FLT CONTROL LOW PRESSURE and FEEL DIFF PRESSS lights illuminate.

With Sys A inop, what do you loose?

The No 1 thrust reverser has standby pressure for deployment , and the landing gear must be extended manually. d

What are the big things with loss of sys b?

Alternate brakes are available, No 2 thrust reverser and leading edge flaps and slats have standby pressure available and the trailing edge flaps are operated electrically.

With a loss of sys _____, the checklist calls for a flaps 15 landing using the ________

B; alternate flap extension.

The loss of both sys A and B is called what?

manual reversion. Indications are all 4 pumps show LOW PRESSURE and both Sys A and B FLT CONTROL LOW PRESSURE lights illuminated

What happens with manual reversion?

Sys A & B FLT CONTROL switches are moved to STBY RUD, the YAW DAMPER is selected ON allowing stby hyd power to power the stby yaw damper, and both Sys A and B switches are selected off.

What is inoperative for manual reversion?

Autopilots A & B ALL flight spoilers Ground spoilers Trailing edge flaps via normal hydraulics Leading edge flaps and slats via normal hydraulics Main landing gear via normal hydraulics nose wheel steering Normal and alternate brakes Autobrake Both Thrust reverservs via normal hyd pressure. Trailing edge flaps are operated electrically Inboard and outboard brakes have accumulator pressure only Manual gear extension is req'd

What is the landing configuration for manual reversion?

Flaps 15 landing using alternate flap extension. Manual gear extension. Once lowered, it can't be retracted.