Systems Flashcards by Harshita Jayal

Ldg gear is subjected to ___ loads while ground manoeuvring, which are often taken ___.

Torsional loads
Taken by torque links

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purpose of FLUID in the upper/ outer cylinder

To dampen oscillations and control the compression and extension of cylinders

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Purpose of gas in the lower/ inner cylinder

Supports the weight of aircraft

cushion bumps during taxing

absorbing shocks during landing

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Normal taxing bumps are ___ by gas and dampened by the ___

Cushioned by gas
Dampened by limited flow of fluid through the orifice

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What prevents locking of ldg gear and extended and retracted positions ?

Mechanical locks of undercarriage

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Tricycle gear u/c

1 nose u/c - helps in steering
2 main u/c - just aft of CG , takes initial loads of landing and 90% of aircraft’s wt

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5 loads acting on ldg gear and its reducing designs

COMPRESSIVE LOADS - during ldg/ taxiing bumps, cushioned OLEO PNEUMATIC STRUTS

REARWARD BENDING - during brakes,
DRAG STRUTS

SIDE LOADS - crosswind t/o, ldg, taxi,
SIDE STRUTS

FORWARD LOADS - during pushback, DRAG STRUT ASSEMBLY

TORSIONAL LOADS - while ground manoeuvring, TORQUE LINKS

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Large airplanes are steered on ground using ___ but almost all of them have means of ___ in failure mode

Nose wheel steering but use castoring in case of failure

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Self centring is achieved by either ___ or ___

Spring loaded cam or
Hydraulic dashpot

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Shimmy can be reduced by using

Hydraulic dampers and heavy self centring springs

Double nose wheels and twin contact wheels

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Device to prevent inadvertent retraction of ldg gear when on ground, consists of a mechanical lock which retains its down position and is released by the operation of a solenoid

Gear selector lever

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___ or ___ are further safety features for inadvertent retraction of ldg gear on ground and are fitted with warning flags

Ground locks or ldg gear locking pins

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In case of ldg if the main system fails, ldg gear extension and locking down psn is done by

Emergency LOWERING system
Electrically in B 747
Mechanically in B 737

Uplocks released , ldg gear falls down under its own wt and downlocks engaged mechanically by springs

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______ system prevents inadvertent retraction of ldg gear on ground and has proximity sensors and micro switches attached to ldg gear oleos

Air/ground logic system , maybe selected on or off when a/c is airborne or not

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Wheel designed to be used in tubeless tyres

Split hub / divided wheel
Which are 2 half wheels connected by bolts

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A value of tyre px specified by Manufactures to prevent creep is ___

Rated inflation pressure which is cold tyre px ( tyre not under load ie a/c)

Rises by 4% when under the wt of aircraft

And by 10% inc when in use for taxi t/o and ldg

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What devices are fitted to prevent sudden blowout in some wheels with tubeless tyres in case hard braking

Fusible plugs/ thermal plugs

Protects the tyres from getting exploded due to overheating by releasing gases in a controlled manner

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Different colours of fusible plugs based on temp

Red in 155 deg celsius
Green in 177 deg celsius
Amber in 199 deg celsius

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Index of strength of a tyre

Ply rating

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Most common tread pattern and purpose

Ribbed tread pattern
Disperses water and helps to prevent aqua planning

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All wx tread pattern not so frequently used

Diamond tread pattern

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Tread pattern used in nose gear of aircraft to deflect water away from engine intakes

Chine tread pattern

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Thinnest area of tyres

Sidewalls
They provide flexibility to tyres and enhances max contact of tyres w the sfc

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Diminishing ability of the brakes to lose its braking power when overheated is called ?

Brake fade

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In case of a wheel or brake fire, the best extinguisher to use is ___

Dry powder

What is a brake drag

Spring inside the brake adjusters stops, it could cause the brake not releasing correctly which is called as a brake drag

Pressurised areas of the aircraft

Px - cockpit fwd and aft cabins fwd and aft cargo holds

unpressurised areas of a/c

Radome Nose u/c bay Main u/c bay Tail cone Centre section Torque box

Aural visual warnings are given when cabin altitude exceeds ____

Exceeds 10,000ft

Outflow valve shuts automatically when cabin altitude exceeds ____

Exceeds 13,000ft

Oxygen masks deployed to half hung psn when cabin altitude reaches ___

14,000ft

Oxford A likely cause of nose wheel shimmy ___

Torque links are damaged

A/C in level flight if cabin altitude increases what happens topressure diff:

decreases

The rate of change of cabin pressure should be kept to the minimum. this IS more importantin ehich phase of flight

IN DESCENT

HUMIDIFIER IS MORE USEFUL IN___

HIGH ALTITUDES

Rate of change of cabin altitude is shown on a

SPECIAL GAUGE

On a ground pressurisation test, if the cabin suffers a rapid de-pressurisation:

water precipitation will occur.

If the discharge or outflow valve closes

SAFETY VALVE LIMITS THE POSITIVE PX DIFF

Safety valves are biased

INWARDS

In a pressurisation circuit the sequence of operation is for the

OUTFOW VALVE BEFORE SAFETY VALVE

The aircraft inhibiting switch connected to the A/C landing gear:

stops pressurising on the ground and ensures that there is no pressure differential.

Ditching Cocks are operated TO SHUT __ VALVES

OUTFLOW VALVES

FIREWALLS CONSTRUCTED WITH WHICH MATERIALS

HEAT RESISTANT STAINLESS STEEL AND TITANIUM ALLOY

MAIN STRUCTURAL MEMBER OF WING AND ITS WITHSTANDING LOADS

SPARS IS THE MAIN COMPONENT OF WINGS WITHSTANDS TORSIONAL AND BENDING LOADS

PHENOMENA IN WHICH WHEN NATURAL FREQ= APPLIED FREQ AND IT BEGINS TO AMPLIFY AND MAY AMPLIFY FLUTTER

RESONANCE

primary purpose of frames or formers

oppose hoop stresses and provide shape and form to the fuselage

SANDPAPER THICK LAYER OF ICE EFFECTS ON LIFT AND DRAG

DECREASES LIFT BY 30% INCREASES DRAG BY 40%

pneumatically inflated boots or rubber boots are mechanical de icing systems in which components of aircraft

wing and tail leading edges of piston engine aircrafts and turbo prop

rubber boots are are made up of

LAYERS OF RUBBERISED FABRIC WHICH ARE INFLATED AND DEFLATED REPEATEDLY

overheating of windscreen by eletrical anti icing system may cause ___ and ___

it may cause vinyl bubbling and discolouration

electrical heating elements in a propeller is fitted in components known as ___

overshoes or boots

___ and __ are components used to transfer power from a stationary unit to rotating unit in a prop de icing system OR Fluid is delivered to a propeller by

SLIP RINGS AND BRUSHES OR SLINGER RINGS AND PIPES (SAME THING)

HOT FLUID SPRAY in de icing is sprayed at temperature and px of ___

temp must be 70deg celsius pressure must be 700kN/m^2

If an aircraft is to be de-iced prior to departure with what conditions of apu and bleed air

APU RUNNING BLEED AIR OFF

With a gas turbine engine,in what conditions should engine anti-icing be selected “ON

WHEN THERE IS VISIBLE MOISTURE AND TEMP BELOW 10DEG CELSIUS

the lowest temp at which liquid gives off vapour to form a ignitable material in air is called

FLASH POINT

octane rating tells us what about the fuel

it tells us about the resistance to detonation when exposed to high temp and high px

mogas is rarely used in engines because of?

low octane rating high volatality carburettor icing vapour locking

_____ is added to fuel to reduce wear in fuel system components

HITEC ( lubricity agent)

_____ is added to fuel to reduce wear in fuel system components

HITEC ( lubricity agent)

black smoke from the exhaust is an indication of ?

OVERPRIMING

fuel jettison is done at what altitude

5000-6000ft AGL

fuelling zones must be extended upto atleast ___m/ft radially from filling or venting areas

6m or 20ft radially

refuelling can be done with pax on board if the fuel which is used is ___

jet A1

A power failure to a capacitive fuel contents system would cause the gauge to:

show full scale deflection low.

n aircraft is equipped with capacitive fuel measuring system. after the fuel is half filled the temperature rises which results in the expansion of fuel by 10% what does the gauge show

the gauge shows the same amount of fuel

A “wide-cut” fuel is:

more flammable than a kerosene type fuel

Fuel is heated to prevent __

to stop ice blocking the low px fuel filter

fuel tank ith capacitive quantity system filled with water instead of fuel will show the gauge as __

MAX full scale high

Systems Flashcards

(70 cards)