Systems Flashcards
Ldg gear is subjected to ___ loads while ground manoeuvring, which are often taken ___.
Torsional loads
Taken by torque links
purpose of FLUID in the upper/ outer cylinder
To dampen oscillations and control the compression and extension of cylinders
Purpose of gas in the lower/ inner cylinder
Supports the weight of aircraft
cushion bumps during taxing
absorbing shocks during landing
Normal taxing bumps are ___ by gas and dampened by the ___
Cushioned by gas
Dampened by limited flow of fluid through the orifice
What prevents locking of ldg gear and extended and retracted positions ?
Mechanical locks of undercarriage
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
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
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
Self centring is achieved by either ___ or ___
Spring loaded cam or
Hydraulic dashpot
Shimmy can be reduced by using
Hydraulic dampers and heavy self centring springs
Double nose wheels and twin contact wheels
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
___ 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
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
______ 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
Wheel designed to be used in tubeless tyres
Split hub / divided wheel
Which are 2 half wheels connected by bolts
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
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
Different colours of fusible plugs based on temp
Red in 155 deg celsius
Green in 177 deg celsius
Amber in 199 deg celsius
Index of strength of a tyre
Ply rating
Most common tread pattern and purpose
Ribbed tread pattern
Disperses water and helps to prevent aqua planning
All wx tread pattern not so frequently used
Diamond tread pattern
Tread pattern used in nose gear of aircraft to deflect water away from engine intakes
Chine tread pattern
Thinnest area of tyres
Sidewalls
They provide flexibility to tyres and enhances max contact of tyres w the sfc
Diminishing ability of the brakes to lose its braking power when overheated is called ?
Brake fade
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
