Hydraulics Flashcards

1
Q

What is the Open Center system normally pressurized at?

A

60 psi

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2
Q

What systems are operated by the open center system

A

Landing gear
Speed brakes
Thrust attenuators
Flaps

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3
Q

When does the system pressurize to 1500 psi?

A

When a hydraulic component requires actuation. (One of the four systems is put in use)

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4
Q

Hydraulic reservoir

A

Mounted under right engine pylon
Pressurized by 23 psi (moves fluid to pump)
2 liters / .54 gallons

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5
Q

Hydraulic fluid type

A

MIL-H-83282

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6
Q

Hydraulic pumps how many gallons per minute

A

1.3 gal at 60 psi

3 gal at 1500 psi

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7
Q

Where is the hydraulic SOV located

A

Between pump and reservoir

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8
Q

What is the hydraulic SOV connected to?

A

Engine Fire Push Button

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9
Q

Flow switches/check valves

A

Prevents reverse flow when and if the pumps provide different pressures.
When closed, causes the HYD FLOW LOW annunciator when flow is below .35 to .55 GPM
Reopens when when above 1.33 GPM

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10
Q

System loading valve / system bypass valve (SBPV)

A

Energizes closed to operate hydraulic systems. (Closes to keep it 1500 psi)
Closes when one of the 4 subsystems are actuated.
Pressure relief cracks at 1350 psi and fully opens at 1500.
HYD PRESS ON annunciation

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11
Q

What do the 4 system control valves do?

A

Electronically de energize OPEN to begin actuation.

Electronically energize CLOSED when cycle is complete

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12
Q

Normal Operation Sequence

A

1: Pilot activates a selected subsystem
2: System bypass valve (SBPV) pressurized the system (closes valve), illuminating HYD PRESS ON annunciation
3: Subsystem control valve opens, allowing for pressurization
4: Subsystem cycle completes, showing the correct cockpit indication
5: Subsystem control valve closes,
6: SBVP opens, back to 60 psi, HYD PRESS ON annunciator extinguishes

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13
Q

What keeps landing gear selector from retracting on the ground

A

Downlock Solenoid

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14
Q

Main Gear

A

Retracts inboard
Door does not cover entire gear when retracted
3 fuse plugs
Visual pop out indicator on actuator when downlock is engaged

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15
Q

Nose gear (doors, degrees and shimmy)

A

3 gear doors
20 degrees steerable with pedals. 64 degrees with braking and diff power
Shimmy damper on top of strut

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16
Q

How is the landing gear locked

A

Uplocks/downlocks
Hydraulics do not hold gear in place
No trapped hydraulic pressure

17
Q

Gear warnings

A

Gear not down and locked when either throttle is below 70%N2 and the air speed is less than 130. Can be silenced

Any gear not down and locked when flaps are beyond 15 degrees

18
Q

Emergency gear

A

Mechanical controls to unlock the gear and pneumatic pressure to extend the lines

19
Q

Speed brakes and complete loss of DC power

A

Speed brakes blow to trail

20
Q

At what N2 will the speed brakes automatically retract

A

85%

21
Q

When do speed brakes automatically extend?

A

Flaps 60 selected and flaps moving past 38 degrees

22
Q

How many limit switches associated with speed brakes?

A

Four

All four must be closed for the SPD BRK EXTEND to remain illuminated

23
Q

What conditions must be met for thrust attenuators to deploy?

A

Throttles within 1/4 inch of idle, and weight on wheels

24
Q

How are thrust attenuators locked into positions

A

Hydraulic pressure

25
Q

Flaps (how are they controlled, and what prevents asymmetrical ops)

A

Electrically controlled and hydraulically actuated.

Interconnecting bellcrank, flap fairlead, and cable system prevent asymmetrical flaps operation

26
Q

How are flaps locked into place?

A

When the flap position matches the preselected position, the solenoid valve closes and the flaps are locked by trapped hydraulic fluid.

27
Q

Flap warnings

A

Audible alert will sound if flaps are extended beyond approach setting without gear down

28
Q

Wheel brakes (type, who’s has cylinders, part of the 4 subsystems?)

A

Disk type brakes
Independent from the rest of the hydraulic system
Power brake cylinders on both pilot and co pilot sides

29
Q

Do we still get power braking with antiskid failure?

A

Yes, but not vice versa.

30
Q

Brake fluid reservoir size

A

1 quart

31
Q

Brake accumulator

A

Maintains pressure when pump is not running

Pre charged with nitrogen

32
Q

What annunciation do we receive if pump pressure is below 750 psi

A

PWR BRK LOW PRESS (POWER BRAKE PRESSURE LOW)

ANTISKID INOP

33
Q

Emergency brake system

A

Pneumatic backup in case of hydraulic failure

DO NOT PRESS BRAKES WHEN USING EMERGENCY BRAKE SYSTEM!!!

34
Q

Max output of 1 hydraulic pump

A

3 gallons per minute

35
Q

HYD FLOW LO illuminates below what output value?

A

.35 to .55 GPM

36
Q

How do you know if you have a hydraulic leak?

A

LH/RH HYD FLOW LOW annunciation

37
Q

Number 1 concern if the HYD PRESS ON annunciation light stays on

A

Heat