Powered by R VAC bus (same side, is normally powered by L VAC)

Landing Gear And Hydraulics Flashcards by Chris H

How many Hydraulic systems are there?

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What is the minimum dispatch quantity for hydraulic fluid in each system?

1=1.5Quarts

2=3Quarts

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What powers the main hydraulic pumps?

The RGB

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What Items are powered by the Number 2 system?

LDG gear
Outboard spoilers
Nosewheel Steering
Emerg brake
Rudder actuator (upper)

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What items are powered by the Number 1 hydraulic system?

Flaps
Antiskid (toe brakes)
Inboard spoilers
Rudder actuator (lower)
PTU

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Loss of fluid in what system would affect landing distance the most?

No1

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What are the 2 ways to turn on the STBY hydraulic pumps?

Select flap, maunually using the switch

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What powers the SPU’s?

L/R VAC buses in opposite. number 2 system will auto switch to R VAC if L fails.

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What is the normal pressure of the Hydraulic pumps

3000PSI

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What is the normal pressure of SPU’s?

2900PSI

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What could bring on ENG HYD PUMP?

loss of pressure (less than 2000PSI) or fluid. I.e. leak or pump failure

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What is the main purpose of the PTU?

Assist the #2 SPU with gear retraction and to prevent the ARPS system activating

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When will the PTU automatically turn on?

Eng oil pressure below 40psi (eng fail) AND gear is retracting.

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Can the PTU help if the #2 system has lost all fluid?

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What powers the Hydraulic quantity gauges?

26V FAC

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With a total loss of both hydraulic systems, what hydraulic actuator will still be operating? How will you know that it is still operating?

2 STBY pressure with no main system pressure.

Upper rudder actuator (#2 system)
via ARPS

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What colour is our hydraulic fluid and what is it called?

SKYDROL, purple

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How can we transfer fluid between reserviours?

normally not possible but there is a procedure on the back of the Air NSN AIP

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HYD FLUID HOT

fluid over 109degC, no actions

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1/2 HYD PUMP

System pressure below 2000PSI. could be a leak or fluid loss.

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Main pump output rate

9.5Gal/min

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SPU output rate

1.5Gal/min

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No. 2 SPU AUX PWR

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What bus powers the number 2 SPU?

LVAC

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when will the #2 SPU be on automatically?

Less than 2000PSI pressure in main system + Weight off wheels

#1/2 SPU hot

Overheat of SPU (no auto off)

What pressure does the PTU run at

2750PSI

PTU flow rate

4.5USG/min

where is the PTU on signal sent from?

a pressure switch on the number 2 side

What failsafes/cutoffs does the system have?

T handle valve (pull fuel off handle) in feed line to main pump, a pressure relief valve in the line before the filter, and the alternate gear release door

What power sources does the ARPS system need to funtion?

18PSI bleed air, #2 SPU (L or R VAC bus)

What does ARPS stand for?

Alternate rudder power supply

When does the RSOV activate?

system pressure below ~30PSI (activated by 18PSI air)

How is the Landing gear controlled and operated?

Electronically controlled through the selection lever, hydraulically controlled

How can we test the LDG gear lights?

Advisory lights test

What do the Amber lights on the Gear panel indicate?

Gear doors open

If an amber gear door light is on after extension or retraction what are the considerations?

Not above 140 kts, Could be the mechanical sequencing valve, or a proximity sensor failure (ask FA to check)

Which hydraulic system does the gear run off

#2`

If there was a loss of hydraulic fluid from the #2 hydraulic system, how would you extend the landing gear?

Alternate gear extension QRH

What component monitors the position of up locks, downlocks and gear door positions?

PSEU

What component ensures that the gear cannot fully extend or retract unless the gear doors are open?

Mechanical sequencing valve

LDG GEAR INOP

Sequence valve failure - doors inop (QRH)

What does the gear inhibit switch do?

isolates the extend signal from the gear position selector

What does opening the alternate gear release door above the F/O do?

Releases pressure in the system back into the reserviours

After an alternate gear extension is nose wheel steering available?

No (run off same line as gear, which has now had all pressure removed)

When should the alternate gear indication lights be used?

alt gear extn or any abnormal indication, QRH

What conditions bring on the gear warning horn

1. P/L's near FI, below 130kts, gear not down 2. P/L's below 50%, flap 15 or more, auto feather not armed 3. One P/L FI, less than 130kts, auto fx not armed. (can be muted on a SE app.)

How many WOW sensors are there?

6 (2 on each gear)

How is the gear down locked?

Main gear is locked down by a horizontal over center strut and springs. Nose gear by a vertical over center drag strut.

Which hydraulic system powers the Nose wheel steering?

What is the max steering angle at high speeds using the NWS

7deg (connected to rudders at high speed)

What is the max steering angle at low speeds using the NWS

60deg

NOSE STEERING

ECU failure More than 60deg nose angle Nosewheel steering off

At what speed (on T/O) does anti skid become available?

10kts

When does Anti skid become available on LDG?

Wheel speed more than 35kts and WOW switch, or 3 secs after touchdown.

How long is the antiskid test?

6secs GND | 3secs AIR

Can antiskid be tested with the gear up?

Vlo?

163kts

Vle?

173kts

Max speed for alt gear extn

140 (doors unsecured - no hydraulic pressure)

After T/O what could cause the gear not to retract?

Gear pin, total fluid loss number 2 system, Hydraulic #2 pump failure and a PTU failure, Leaving the alt gear extn door open (overhead=all gear, floor=mains only), PSEU or mechanical sequencing valve failures

What direction does the main gear extend in?

Forward into the airflow

What direction does the nose gear extend in?

Rearwards with the airflow

Where is the lever to manually pressurise the park brake?

RH rear engine nacelle

Does the gear have up locks?

Yes. main gear has physical uplocks (u shape), nose gear is held in place by over center lock bothup and down)

What powers the gear selector switch?

ESS bus

What does a red light mean on the gear selector panel and what do we do?

Gear unsafe or proxy sensor failure. QRH

Will the gear still retract with the gear inhibit switch on?

Yes, only inhibits the down selection

How many proxy sensors are there on the AC total?

If a green light is on (regardless of other lights) what does this mean?

gear is safe

How can we open the Landing gear bypass valve?

ALT gear extn cover on F/O roof (mechanical link)

How do the alternate verification lights work?

Infrared beams through holes to recievers only when the gear is down and locked.

ALT GEAR IND FAIL

Alternate gear extn in flight verification has identified a fault and has disabled a sensor. Turning on alternate verification lights will show you which one has failed (no light)

When do you use the alternate gear extn

when the QRH says to

If the gear does not lock down after alternate gear extension how can we complete the extension?

Using the manual hydraulic pump handle in the alternate gear floor panel and the handle behind the FO's seat. This operates an independant hydraulic system and actuator.

Where is the reserviour for the alternate gear extension

In the nose (1.25Q)

What would it mean if there is a squelchy sound coming from the nose after take off when the gear is selected up?

main hydraulic system is in hydraulic lock, pushing against the alt gear release. CLOSE THE ROOF DOOR.

What would happen if a wheel fell off?

Nothing, only require one per side

What fills the tyres

nitrogen

Can you take off with a tyre that has no tread grooves but isnt showing canvas?

Yes but advise engineers

Which System controls the Emergency brake?

Right/2

What is the minimum pressure for the park brake before engine start

1500PSI

where is the external park brake pressure indicator located?

RH wing root fairing

Below what pressure does the external gauge read inaccurately?

1000PSI (nitrogen pressure)

How many applications does the park brake accumulator allow for?

minimum 4

When is the NWS active?

WOW plus Ldg gear down.

TOUCHED RWY

Tailstrike

WT ON WHEELS

a WOW sensor has failed

how can we pressurise the park brake with the engines off?

manually by a pump in the RH eng nacelle

when will the anti skid self test?

when its turned on + gear down

below what speed is the anti skid unavailable?

10kts

When is the anti skid activated on landing?

wheel speed over 35kts +wow or 3 secs after touchdown.