Hydraulics Flashcards
1
Q
What happens if centre hydraulic system quantity is sensed low?
A
- 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
2
Q
What systems power the Flight controls?
A
- All 3
3
Q
What does the RAT do?
A
- 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
4
Q
What does the Pitch enhancement system do and when does it activate?
A
- 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
5
Q
What systems have reservoirs? Are they pressurised?
A
- Each system has own reservoir
- PRESSURIZED from bleed air
6
Q
How is the centre hydraulic system demand pump powered?
A
- By the Pneumatic system
7
Q
Does the centre Air Demand pump ever Auto operate?
A
- 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
8
Q
What Hydraulic pump is load shed and when?
A
- The C2 pump
- Load shed when on GND and only one source of electrical power
- APU, EXT PWR or 1 ENG GEN
9
Q
Does an autopilot become inop when the left hydraulic system fails?
A
- Yes the Left autopilot
10
Q
When will an RF appear on the hydraulic system quantity?
A
- Below 0.75
11
Q
When does the QTY light illuminate on the overhead panel and what other indication do you get with this?
A
- Below .48
- Also illuminates HYD QUANTITY EICAS advisory message
12
Q
When does the RAT deploy automatically?
A
- 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
13
Q
When does the tail skid extend and retract and what powers it?
A
- Extends and retracts with LDG gear
- Powered by the Centre HYD system
14
Q
Using Alternate Gear extension does the tailskid extend?
A
- No
15
Q
When do the gear doors stay open?
A
- If there is no pressure in the centre hydraulic system after an Alternate gear extension
- GEAR DOORS displays on EICAS
16
Q
Is anti skid available in the alternate brake system?
A
- 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
17
Q
How are the nose and main gear held in the up and locked position?
A
- Nose gear - up locks
- Main Gear - door structure
18
Q
What does the green PRESS light on the RAT panel indicate?
A
- RAT is deployed and RAT is producing hydraulic pressure
19
Q
When does Auto braking application commence on touchdown?
A
- Both thrust levers retarded to idle
- Wheels have spun up
- Nose attitude is less then 1 degree
20
Q
What does touchdown protection provide?
A
- Ensures rear wheel brakes do not have hydraulic pressure at touchdown
21
Q
How does the braking system provide hydro planning protection?
A
- Compares IRS ground speed to wheel speed and decreases aft wheel brake pressure when ground speed is greater then wheel speed
22
Q
How does the braking system provide locked wheel protection?
A
- 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
23
Q
What powers the Elevators?
A
- Right, Center & Left systems
- Can still power if 2 systems lost
24
Q
Does Autopilot trim at the same rate as electric or manual?
A
- No it trim as at one half the rate as it has only one trim control module
25
When are the Electric trim switches inhibited?
* During auto-land or Go-around with multiple autopilots engaged
26
What are the 2 types of unsched stab trim?
* Stabilizer moves without a trim signal
* Stabilizer movement is opposite the direction signalled
27
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
28
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
29
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
30
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
31
What does the failure of a one Yaw Damper do?
* Reduces the total yaw damping authority by one half
32
What does no white band indicate on the stab trim indicator?
* Stab trim indicator malfunctions other than power failure
33
How many ailerons are there?
* 2 each wing- inboard and outboard
34
How many spoilers are there?
* 12
* 6 each wing
* 2 x inboard
* 4 x outboard
35
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
36
What do the ailerons do with flap extension?
* The inboards droop in conjunction with trailing edge flap extension
37
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
38
Are ailerons ever locked out?
* Yes at high speeds
* Prevents operation of outboard ailerons to protect against over controlling
39
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
40
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
41
When do the speedbrakes automatically retract?
* When thrust levers are moved from idle on ground
42
When does the SPEEDBRAKES EXT and Caution appear?
* Speedbrakes extended when RAD ALT is 800ft or below **or:**
* Flaps are in landing position
43
How are the flaps and slats powered in the Normal and Alternate operation?
* NORMAL - Hydraulic powered
* ALTERNATE - Electric
44
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
45
What happens when flaps are moved to position 1?
* Just the slats extend to takeoff position
46
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
47
What happens at Flaps 25 & 30?
* Slats extend to their landing position
* Flaps extend to selected position
* Inboard ailerons droop
48
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
49
How does the ALTN FLAPS work and what has priority?
* Driven by electric motor
* Overrides flap lever control inputs
50
How long does the ALTN system take to extend to Flaps 20?
* 3 minutes
51
Do you still have Flap Load relief protection during ALTN flaps selector?
* No flap load relief in alternate
52
Does the ALTN slat switch provide asymmetry protection?
* No slat assymetry protection provided
53
What system powers the spoilers?
Long range cruise cuts costs lots - for Left wing??
Long range cruise cuts costs right - for right wing??
54
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
55
What does the Center hydraulic system power in regards to the LDG gear?
* Retraction, extension & steering
* Alternate brake system
56
What brake system are autobrakes provided with?
* Only normal system not alternate
57
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
58
Rudder ratio changer powered by?
* Left system only and has only one actuator
59
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
