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HERC CONVERSION > HYDRAULICS EXAM REVISION > Flashcards

HYDRAULICS EXAM REVISION Flashcards

(60 cards)

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1
Q

What are the 3 hydraulic systems?

A
  • Utility system
  • Auxiliary system
  • Booster system
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2
Q

Utility system;

  • pressurised by?
  • what 5 systems does it supply?
A

Two engine driven pumps; Number 1 & 2 engines

  • Landing gear
  • Normal brakes
  • Nose wheel steering
  • Flaps
  • Half of each primary flight control boost assys
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3
Q

Booster system;

  • pressurised by?
  • what systems does it supply?
A

Two engine driven pumps; Number 3 & 4 engines

- The other half of the primary flight control boost assys

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4
Q

Auxiliary system;

  • pressurised by?
  • what systems does it supply?
A

Either 3 phase ESS AC driven pump or hand pump

  • Cargo ramp & door
  • Emerg brakes
  • Emerg NLG extension system
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5
Q

What can occur between the Aux and the Utility system on the ground, why?
- What is the valve called?

A

The two systems can be “tied” together which allow operation of ALL hyd services without needing to run the engines
- Ground test valve

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6
Q

Reservoir capacities;

  • Utility reservoir;
  • Booster reservoir;
  • Auxiliary reservoir;
A
  • Utility reservoir; 3.2 US GAL
  • Booster reservoir; 2.0 US GAL
  • Auxiliary reservoir; 3.4 US GAL
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7
Q

Utility suction boost pump;

Purpose & NUMBER?

A

Provides a positive head of pressure (70-100psi) to the engine driven pumps

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8
Q

Utility suction boost pump; thermal protection?

A

Provided by a circuit that will cut power to the motor at approx 11 amps

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9
Q

Utility engine driven pumps; output

A

Up to 8.6 US GAL/min at 2900 to 3200 psi

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10
Q

What controls the pressure of the EDPs?

A

A pressure compensator which varies the angle of the wear plate which controls piston & therefore amount of fluid pumped.

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11
Q

What kicks in if the EDP compensator fails? NUMBERS?

A

A pressure relief valve provides protection against overpressure by relieving pressure back to reservoir via return line
- Set to crack at 3450psi & open by 3850psi

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12
Q

Accumulator

  • Purpose
  • Charged to?
A
  • is installed to absorb hydraulic shock & provide reservoir of fluid under pressure to meet max peak requirements
  • Charged to 1500 +/- 100psi
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13
Q

Auxiliary hyd system; Aux pump

- NOTE

A

Wait at least ten seconds after pump is turned off before turning back on, otherwise the motor will be overloaded & CBs will pop

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14
Q

Utility & Booster system;

  • What are the two Shutoff valves
  • How are they actuated
A
  • Firewall shutoff valve (suction) & Pressure line shutoff valve
  • By the indicator switches or the fire handle
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15
Q

Utility & Booster system; Describe:

  • Firewall shutoff valve (suction)
  • Pressure line shutoff valve
A
  • A sliding gate type valve that isolates the engine driven pump from its supply (slow)
  • A solenoid operated valve that shuts off the engine driven pump output (fast)
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16
Q

Utility & Booster system; Why are the two Shutoff valves varied in closing speed?

A

The firewall shutoff valve is slower to operate so as to allow more fluid into the system before closing to provide a cooling & lubrictation circuit for the pump (which will still be turning)

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17
Q

Auxiliary hyd system; Aux pump

- Output pressure

A
  • 2900 to 3300psi
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18
Q

Auxiliary hyd system; pressure transmitter

- What will it not do & why

A

Because of its position, it will not read pressure from the handpump - reads aux pump pressure only

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19
Q

If you turn the aux pump on, on the ground with no engines running, what gauges will show pressure;

  • Systems not tied
  • Systems tied
A
  • Systems not tied: Aux pump & emergency brake indicators

- Systems tied: Aux pump/emergency brake/normal brakes/utility/rudder pressures

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20
Q

What conditions is the normal hyd pressure range based on for utility & booster systems? (4)

A
  • 100% RPM
  • All flt controls in neutral
  • Suction boost pumps on
  • No system actuation
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21
Q

What low pressure reading is acceptable during LSGI ops

A

2550psi

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22
Q

Utility & booster systems; under what conditions is the MASTER CAUTION output active
- Why is utility lower?

A

Whenever ONE exists;

  • UTILITY indicator is <2700 or >3500 psi
  • BOOSTER indicator is <2900 or >3500 psi

Because of extra draw from the MLG

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23
Q

What is the name of the valve that controls the ramp & door

- how do we actuate it?

A
  • manifold control valve

- Either mechanically or manually

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24
Q

Ramp lock mechanism

- How does it work

A
  • Single hyd cylinder is linked to series of cranks & push/pull rods that actuate 5 hooks on each side of ramp.
  • Hooks engage to mechanically lock the complete mechanism & the ramp in place
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25
How is the door held locked up?
A rod attached to front of door will engage mechanically with uplock
26
What is the ADS position of the ramp? What indication is there in the flight deck when ramp is in this position? What else is armed when in this position?
- Horizontal - A green 'OPEN' light will illuminate on the ADS switch - The chute release switch
27
Air deflectors: | - purpose
- serve as windbreak for paratroops
28
Limitations; paratroop doors - During opening & closing doors - Whilst doors are open
- During opening & closing doors: MAX 150KIAS | - Whilst doors are open: MAX 250KIAS
29
Limitations; paratroop air deflectors
Max 150KIAS during operation or once deflectors are open
30
Limitations; aft cargo door and/or ramp - Ramp (and/or cargo door) open - Ramp closed & locked & cargo door open & locked
- Ramp (and/or cargo door) open; 150KIAS max | - Ramp closed & locked & cargo door open & locked; 185KIAS max
31
Air deflectors: Switch settings
- Select either switch to OPEN: opens both deflectors - Select either switch to CLOSE: closes both deflectors - CLOSE has priority
32
Shock struts purpose & type
provide shock absorbing for MLG | Soft struts
33
MLG; general overview of how it is lowered/raised
Two shock struts are raised/lowered in vertical racks by means of ball nuts & screw jacks.
34
Drag pins; purpose?
- Ensures that MLG horizontal loads are transferred to the fuselage through the shelf bracket (not through the screwjack/guide assy)
35
What are the cables and handles on the side of the screwjack do?
Pull the handle which mechanically repositions the clutch and allows the handcrank to crank the gear down
36
What strut is the gear door manually hooked up to?
The aft strut
37
What selection do we use in the cockpit to extend/retract the gear? What do we have if this doesn't work?
- The gear handle | - The landing gear control valve has two override buttons to provide manual control over solenoids
38
What does the down detent on the landing gear control valve do?
Ensures the main spool remains in the down position if positioned there and power is lost
39
What else is incorporated into the gear handle & what is its purpose?
Mechanical "j" hook that prevents up selection of the gear on the ground
40
NLG extension/retraction actuator pin; purpose?
Prevents the NLG from collapsing on the ground by blocking a piston from being able to move the lugs to retract the gear
41
How do you visually check the NLG is down & locked?
Visual locking indicator can be checked through inspection panels
42
How is the NLG held up and locked?
Hydro/mechanical latch assy that engages with a link attached to the lower end of NLG strut.
43
LDG gear warning system; under what conditions with you get a red light and/or gear horn?
- Landing gear is not in a locked position (red light only) - A throttle is retarded to within 5deg flight idle and gear is not down & locked (Red light & horn) - Flaps are selected to more than 70% and gear is not down and locked (Red light & horn)
44
What are the 5 alternate methods of gear operation?
- Overriding the landing gear selector valve procedure - Manual gear extension (MLG) procedure - Emergency hydraulic extension (NLG) procedure - NLG manual extension (freefall) procedure - MLG extension after normal and emergency system failure procedure
45
Overview of how NLG steering works & how many degrees movement?
Uses utility hydrualic pressure to turn lower piston portion of NLG shock strut up to 60deg L/R
46
What are the two brake systems?
- Normal | - Emergency
47
If a loss of electrical power occurs, what occurs for the braking system & what system pressure does the emergency brake system use?
The system with the higher pressure will operate brakes
48
What is the purpose of the brake fuses?
valves that prevent complete loss of hyd fluid should a leak occur, by closing after a certain amount of fluid has passed
49
Brake control valves; | - What do they limit max brake pressure to?
- limit max brake pressure to 2030psi
50
Landing gear limits; max extended speed of gear
165KIAS
51
Normal brake pressure caution zone (minimum)
2900 to 2250 psi | 2250psi is minimum
52
Nose wheel steering limits; - Weight exceeds 150,000lbs - Taxi speed >20kts - Nose wheel at 60deg
- Weight exceeds 150,000lbs; 20deg - Taxi speed >20kts: 20deg - Nose wheel at 60deg: 5kts
53
Max tyre rotation speed - Nose: - Main:
- Nose: 139kts | - Main: 174kts
54
Why do we flight control boost shutoff valves?
Used to isolate the booster package from respective hydraulic system should a leak/malfunction occur in booster package
55
What are the configuration of the booster packs?
- Aileron & rudder: tandem config | - Elevator: Dual config (side by side)
56
Asymmetry system; | - Function
- Senses certain malfunctions in flap drive system and actuates emergency flap brakes to stop further movement
57
Asymmetry system; warning associated
Do not release the manual override on emergency flap valve while a/c is in flight
58
General actions for EDP failure
- Pump turned OFF - Check hyd reservoir level; > fluid normal: continue flight > fluid decreasing: follow HYD PRESSURE/FLUID LOSS cxlist
59
Anti skid system; the three modes of operation & brief description
- Anti skid control: wheel speed decreases rapidly, valve reduces pressure to affected brake - Positive locked wheel protection: One wheel is locked, brake pressure is completely released - Threshold control: a/c is a/b & gear is down, brakes are not applied until a/c is on the ground & taxiing faster than 15kts
60
Flaps limitations (KIAS TO %)
``` 10/10/10/10/15/10/5/5/0 10 - 220KTS 20 - 210KTS 30 - 200KTS 40 - 190KTS 50 - 180KTS 60 - 165KTS 70 - 155KTS 80 - 150KTS 90 - 145 KTS 100 - 145 KTS ```

HERC CONVERSION (18 decks)

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