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Flashcards in Hydraulics Deck (59):

What happens if centre hydraulic system quantity is sensed low?

  • Centre 1 elec pump is automatically isolated to provide hydraulic pressure to the RESERVE BRAKES & STEERING
  • The ISLN light for C HYD SYS on the rear panel illuminates


What systems power the Flight controls?

  • All 3


What does the RAT do?

  • Provides hydraulic pressure to the flight controls portion of the Centre Hydraulic System
  • Provides adequate hydraulic power for flight controls at speeds above 130kt
  • Deploys automatically when both engines fail (Engines drop BLW idle)
  • Cannot be stowed in flight
  • In right wheel well


What does the Pitch enhancement system do and when does it activate?

  • Auto activates if the Left & Centre HYD systems fail and trim switches are used
  • A pump in the right system uses trapped left system fluid to operate the stabilizer
  • Elec trim is available at approx 1/4th of the rate
  • Alternate and auto trim inop


What systems have reservoirs? Are they pressurised?

  • Each system has own reservoir
  • PRESSURIZED from bleed air


How is the centre hydraulic system demand pump powered?

  • By the Pneumatic system


Does the centre Air Demand pump ever Auto operate?

  • Yes when there is a large demand on the centre system such as when operating the landing gear, flaps/slats and ground spoilers
  • Pump also operates whenever system pressure is low
  • Air supply valve opens and pump operates to provide additional system pressure


What Hydraulic pump is load shed and when?

  • The C2 pump
  • Load shed when on GND and only one source of electrical power


Does an autopilot become inop when the left hydraulic system fails?

  • Yes the Left autopilot


When will an RF appear on the hydraulic system quantity?

  • Below 0.75


When does the QTY light illuminate on the overhead panel and what other indication do you get with this?

  • Below .48
  • Also illuminates HYD QUANTITY EICAS advisory message


When does the RAT deploy automatically?

  • When both engines fail in flight (both sensed below idle)
  • Provides adequate power for operation of the flight controls portion of the centre hydraulic system at airspeeds ABV 130kts


When does the tail skid extend and retract and what powers it?

  • Extends and retracts with LDG gear
  • Powered by the Centre HYD system


Using Alternate Gear extension does the tailskid extend?

  • No


When do the gear doors stay open?

  • If there is no pressure in the centre hydraulic system after an Alternate gear extension
  • GEAR DOORS displays on EICAS


Is anti skid available in the alternate brake system?

  • Yes provided in normal and alternate systems
  • NORMAL - Each making gear wheel is provided with individual anti skid protection
  • ALTERNATE - Provided to laterally paired wheels


How are the nose and main gear held in the up and locked position?

  • Nose gear - up locks
  • Main Gear - door structure


What does the green PRESS light on the RAT panel indicate?

  • RAT is deployed and RAT is producing hydraulic pressure


When does Auto braking application commence on touchdown?

  • Both thrust levers retarded to idle
  • Wheels have spun up
  • Nose attitude is less then 1 degree


What does touchdown protection provide?

  • Ensures rear wheel brakes do not have hydraulic pressure at touchdown


How does the braking system provide hydro planning protection?

  • Compares IRS ground speed to wheel speed and decreases aft wheel brake pressure when ground speed is greater then wheel speed


How does the braking system provide locked wheel protection?

  • Compares the speed of each fore and aft wheel pair
  • Releases hydraulic pressure from the slower wheel when the speed difference is greater than 25kts


What powers the Elevators?

  • Right, Center & Left systems
  • Can still power if 2 systems lost


Does Autopilot trim at the same rate as electric or manual?

  • No it trim as at one half the rate as it has only one trim control module


When are the Electric trim switches inhibited?

  • During auto-land or Go-around with multiple autopilots engaged


What are the 2 types of unsched stab trim?

  • Stabilizer moves without a trim signal
  • Stabilizer movement is opposite the direction signalled


What do the STAB TRIM CUTOUT switches do when in NORM & CUTOUT?

  • NORM - keeps hydraulic supply shutoff open
  • CUTOUT- shuts off respective Center or Left hydraulic system power to the related stab trim control module


What powers the rudder? Can it still operate if two systems are lost?

  • Pedals control 3 hydraulic actuators that move the rudder
  • Each system powers one
  • Can still operate if two systems lost but displacement limited


What does the Rudder ratio changer do?

  • Uses airspeed information to vary the amount of rudder displacement providing structural protection for the rudder
  • LOW SPEEDS = Full displacement
  • HIGH SPEEDS = Limited displacement
  • Powered by the LEFT hydraulic system


What happens if there is a rudder ratio changer fault?

  • Left HYD system automatically rudder actuator automatically depressurises to provide structural protection for the rudder
  • RUDDER RATIO - EICAS message displays


What does the failure of a one Yaw Damper do?

  • Reduces the total yaw damping authority by one half


What does no white band indicate on the stab trim indicator?

  • Stab trim indicator malfunctions other than power failure


How many ailerons are there?

  • 2 each wing- inboard and outboard


How many spoilers are there?

  • 12
  • 6 each wing
  • 2 x inboard
  • 4 x outboard


What system powers the ailerons? How many to have aileron control?

  • All three power them
  • If one or two systems are lost you still have aileron control


What do the ailerons do with flap extension?

  • The inboards droop in conjunction with trailing edge flap extension


When if ever are spoilers inhibited from responding to control wheel commands?

  • At cruise speed
  • Two spoilers on each wing are inhibited this prevents over controlling


Are ailerons ever locked out?

  • Yes at high speeds
  • Prevents operation of outboard ailerons to protect against over controlling


How many spoilers are used with the the Speedbrake lever inflight?

  • All but 2 are used
  • 4 & 9 (3rd from the fuselage, the first outboard)
  • Should not be used with flap greater than 5 to avoid buffeting


When will the speedbrakes extend if in the armed position?

  • Thrust levers idle
  • HYD pressure to gear tilt actuators
  • Sensors detect airplane on the ground


When do the speedbrakes automatically retract?

  • When thrust levers are moved from idle on ground


When does the SPEEDBRAKES EXT and Caution appear?

  • Speedbrakes extended when RAD ALT is 800ft or below or:
  • Flaps are in landing position


How are the flaps and slats powered in the Normal and Alternate operation?

  • NORMAL - Hydraulic powered
  • ALTERNATE - Electric


How many slats are there?

  • 10 outboard (5 a wing)
  • 2 inboard (1 a wing)
  • Center HYD system powers through 3 separate power drive units


What happens when flaps are moved to position 1?

  • Just the slats extend to takeoff position


What happens with flaps 5, 15 & 20?

  • Slats remain in takeoff position
  • Flaps extend to required position
  • Inboard ailerons droop in conjunction with flap extension


What happens at Flaps 25 & 30?

  • Slats extend to their landing position
  • Flaps extend to selected position
  • Inboard ailerons droop


When does the flap load relief system arm and what does it do?

  • Arms at flaps 25 or 30
  • Retracts flaps position to 20
  • Prevents flap extension to position 25 and 30
  • Automatically reselects flap after speed is ok
  • Slats remain in LDG config


How does the ALTN FLAPS work and what has priority?

  • Driven by electric motor
  • Overrides flap lever control inputs


How long does the ALTN system take to extend to Flaps 20?

  • 3 minutes


Do you still have Flap Load relief protection during ALTN flaps selector?

  • No flap load relief in alternate


Does the ALTN slat switch provide asymmetry protection?

  • No slat assymetry protection provided


What system powers the spoilers?

Long range cruise cuts costs lots - for Left wing??

Long range cruise cuts costs right - for right wing??


When is the alternate brake system pressurized and from where?

  • When right side pressure is low
  • The center system automatically supplies pressure to the alternate system


What does the Center hydraulic system power in regards to the LDG gear?

  • Retraction, extension & steering
  • Alternate brake system


What brake system are autobrakes provided with?

  • Only normal system not alternate


How many power sources does each hydraulic system have?

Left and Right have 2 sources:

  • 1 engine driven pump
  • 1 AC pump which operates on demand

Center has 4 sources:

  • 2 AC pumps
  • 1 Air Driven Pump which operates on demand
  • 1 RAT


Rudder ratio changer powered by?

  • Left system only and has only one actuator


Why do you depressurize the right HYD system last?

  • C & R systems share a part of the brake lines
  • If R system is turned off prior to C system the brake source is changed to the C system and fluid transfer from R to C system occurs