11.13 Landing Gear Flashcards
(219 cards)
1
Q
What is the main purpose of the aircraft landing gear?
A) To assist with in-flight maneuverability
B) To support weight and absorb loads during ground operations
C) To reduce engine vibration
A
B) To support weight and absorb loads during ground operations
2
Q
Which landing gear configuration has the main gear forward of the center of gravity and a tail wheel?
A) Tricycle
B) Tandem
C) Tail wheel
A
C) Tail wheel
3
Q
What advantage does tricycle-type landing gear provide?
A) Greater lift during takeoff
B) Improved rearward visibility
C) Prevention of ground looping
A
C) Prevention of ground looping
4
Q
Which landing gear configuration has gear aligned along the aircraft’s longitudinal axis?
A) Tricycle
B) Tandem
C) Tail wheel
A
B) Tandem
5
Q
What is the function of a torsion link damper (shimmy damper)?
A) To absorb vertical shock loads
B) To counteract wheel shimmy
C) To reduce aerodynamic drag
A
B) To counteract wheel shimmy
6
Q
What is a bogie in the context of landing gear?
A) A single-wheel nose gear
B) A wheel configuration with multiple wheels per leg
C) A retractable gear mechanism
A
B) A wheel configuration with multiple wheels per leg
7
Q
Which landing gear component resists lateral movement?
A) Drag strut
B) Side strut
C) Actuator
A
B) Side strut
8
Q
What does the drag strut (or drag brace) do?
A) Connect the gear to the wheel
B) Brace the leg against longitudinal movement
C) Absorb vertical landing loads
A
B) Brace the leg against longitudinal movement
9
Q
What is the purpose of the downlock mechanism?
A) To retract the landing gear
B) To lock the gear in the up position
C) To prevent the gear from folding when extended
A
C) To prevent the gear from folding when extended
10
Q
What component is used to initiate gear retraction?
A) Torsion link
B) Trunnion
C) Extend and retract actuator
A
C) Extend and retract actuator
11
Q
Why do some aircraft have a landing gear shortening mechanism?
A) To reduce gear maintenance
B) To decrease gear drag
C) To fit the gear into limited bay space
A
C) To fit the gear into limited bay space
12
Q
Which component helps shorten the gear during retraction?
A) Jacking point
B) Bellcrank lever
C) Downlock pin
A
B) Bellcrank lever
13
Q
What is the primary function of the Nose Landing Gear (NLG)?
A) To absorb initial landing impact
B) To carry the main aircraft load
C) To support and steer the aircraft on the ground
A
C) To support and steer the aircraft on the ground
14
Q
Which feature helps align nose wheels for retraction?
A) Shimmy damper
B) Centring cam
C) Shock strut
A
B) Centring cam
15
Q
How is the nose gear typically extended if hydraulic power is unavailable?
A) Manually cranked
B) Spring-loaded deployment
C) By air stream and gravity
A
C) By air stream and gravity
16
Q
What are the two main types of shock absorbing systems?
A) Electric and pneumatic
B) Hydraulic and oleo-pneumatic
C) Solid and oleo-pneumatic
A
C) Solid and oleo-pneumatic
17
Q
What causes hydraulic dieseling?
A) Excessive nitrogen pressure
B) Mixing of air and hydraulic oil
C) Low strut temperature
A
B) Mixing of air and hydraulic oil
18
Q
How does an oleo-pneumatic strut without a separator work during landing?
A) Gas is vented to the atmosphere
B) Oil and gas mix directly
C) Fluid flows through a tapered metering pin
A
C) Fluid flows through a tapered metering pin
19
Q
In an oleo-pneumatic strut with a separator, what keeps oil and gas from mixing?
A) Flutter valve
B) Separator piston
C) Torsion links
A
B) Separator piston
20
Q
What component restricts fluid return flow during strut extension in a strut with separator?
A) Metering pin
B) Centring cam
C) Flutter valve
A
C) Flutter valve
21
Q
What is the purpose of dimension ‘X’ during landing gear servicing?
A) To check wheel alignment
B) To ensure correct strut extension
C) To measure oil level
A
B) To ensure correct strut extension
22
Q
What should be done if the measured dimension ‘X’ does not match the graph?
A) Replace the torsion links
B) Adjust the brake pressure
C) Add or release nitrogen
A
C) Add or release nitrogen
23
Q
What system is most commonly used for landing gear retraction in aircraft?
A) Electrical system
B) Pneumatic system
C) Hydraulic system
A
C) Hydraulic system
24
Q
What mechanism ensures that the landing gear stays in the extended or retracted position?
A) Proximity switches
B) Positive mechanical locks
C) Solenoid actuators
A
B) Positive mechanical locks
25
How are landing gear wheel bay doors typically operated?
A) By electric motors
B) By hydraulic actuators or mechanical rods
C) By cable and pulley systems
B) By hydraulic actuators or mechanical rods
26
What prevents inadvertent gear retraction on the ground?
A) Hydraulic sequencer
B) Emergency release handle
C) Latch mechanism in the control lever
C) Latch mechanism in the control lever
27
What is the purpose of the gear indication system?
A) To lower the gear in an emergency
B) To alert the crew to gear and door positions
C) To monitor hydraulic pressure
B) To alert the crew to gear and door positions
28
What are the three typical positions of a landing gear control lever?
A) Up, Down, Emergency
B) Off, Standby, Extend
C) Up, Off, Down
C) Up, Off, Down
29
What prevents accidental lever movement due to vibration?
A) Spring lock
B) Detent positions
C) Safety pin
B) Detent positions
30
What does moving the lever to the 'Off' position do?
A) Activates the brakes
B) Connects gear actuators directly to return
C) Depressurises the landing gear system
C) Depressurises the landing gear system
31
On modern aircraft, what component often controls the landing gear operation sequence?
A) Manual override
B) Micro or proximity switches and a computer
C) Hydraulic pump controller
B) Micro or proximity switches and a computer
32
How can the solenoid preventing gear retraction on the ground be overridden?
A) Electrically
B) Automatically
C) Mechanically
C) Mechanically
33
What is the purpose of correct sequencing in landing gear and door systems?
A) To minimize noise
B) To prevent the gear from becoming jammed
C) To save hydraulic pressure
B) To prevent the gear from becoming jammed
34
What unlocks the down-locks during main gear retraction?
A) A lever override
B) Pressurised hydraulic fluid
C) The door actuator
B) Pressurised hydraulic fluid
35
What causes gear door actuators to receive hydraulic fluid during retraction?
A) Electrical signal from cockpit
B) Mechanical contact with sequence valve plungers
C) Manual control
B) Mechanical contact with sequence valve plungers
36
What prevents gyroscopic forces on the gear during retraction?
A) Nose centring cam
B) Brake application
C) Down-lock actuator
B) Brake application
37
What component aligns bogie wheels for retraction on certain aircraft?
A) Bogie tilt jacks
B) Nose wheel actuator
C) Door sequencer
A) Bogie tilt jacks
38
What holds the gear in place after retraction?
A) Door locks
B) Spring tension
C) Up-lock roller and hook
C) Up-lock roller and hook
39
When should the gear selector lever be moved to the off position in flight?
A) After takeoff
B) When extending the gear
C) After gear is confirmed up and locked
C) After gear is confirmed up and locked
40
How is the nose wheel centred before retraction?
A) External hydraulics
B) Steering linkage
C) Internal cams in the shock strut
C) Internal cams in the shock strut
41
What happens first when lowering the gear?
A) Gear down-locks are engaged
B) Main gear actuators extend
C) Doors are opened
C) Doors are opened
42
What do sequence valves A and B do during extension?
A) Delay nose gear deployment
B) Block fluid to main gear actuators until doors are open
C) Extend the gear directly
B) Block fluid to main gear actuators until doors are open
43
Why are restrictors used in the orifice check valves during gear extension?
A) To maintain pressure
B) To reduce fluid temperature
C) To slow extension and prevent impact damage
C) To slow extension and prevent impact damage
44
What ensures controlled nose gear extension?
A) Mechanical override
B) Restricted return flow
C) Pilot visual inspection
B) Restricted return flow
45
What causes the nose gear centring cams to disengage?
A) Selector lever movement
B) Manual override
C) Weight applied to the leg on landing
C) Weight applied to the leg on landing
46
What is the primary method used in large commercial aircraft for emergency gear extension?
A) Pneumatic pressure
B) Freefall system
C) Manual cranking
B) Freefall system
47
What must be done before using the emergency extension handle?
A) Open the gear doors
B) Turn off electrical power
C) Move the gear selector to the off position
C) Move the gear selector to the off position
48
What ensures the gear can fall under gravity during emergency extension?
A) Releasing up-locks
B) Fluid pressurisation
C) Steering control
A) Releasing up-locks
49
What indicates successful down-lock in case the main indicators fail?
A) Audio alert
B) Hydraulic pressure gauge
C) Gear down-lock viewers
C) Gear down-lock viewers
50
What do mechanical emergency release systems do in some aircraft with two-position levers?
A) Activate the nose wheel steering
B) Dump hydraulic fluid return lines
C) Close the gear doors
B) Dump hydraulic fluid return lines
51
Why do some small aircraft require mechanical force for emergency gear extension?
A) They lack a freefall system
B) Their gear is electrically controlled
C) Airflow is insufficient
A) They lack a freefall system
52
What reference should be used for emergency landing gear systems maintenance?
A) Aircraft Logbook
B) Operations Manual
C) Aircraft Maintenance Manual (AMM)
C) Aircraft Maintenance Manual (AMM)
53
What visual indication is shown when a landing gear is down and locked?
A) Red light
B) No light
C) Green light
C) Green light
54
What causes the gear disagreement light to illuminate?
A) A failed microswitch
B) A mismatch between control lever position and gear position
C) Landing flap deployment
B) A mismatch between control lever position and gear position
55
Where are the position sensors located in the landing gear system?
A) On the brake lines
B) On each gear’s downlock, uplock, and door lock
C) On the hydraulic selector valve
B) On each gear’s downlock, uplock, and door lock
56
What is the most common reason for a gear indication light failing to illuminate?
A) Faulty microswitch
B) Corrosion
C) Bulb failure
C) Bulb failure
57
What happens to the gear position lights when the gear is fully retracted?
A) They change from green to red
B) They extinguish
C) They flash continuously
B) They extinguish
58
What type of indication systems are used on modern aircraft to show gear position besides control lever lights?
A) GPS and radio signals
B) ECAM or EICAS displays
C) Brake pressure sensors
B) ECAM or EICAS displays
59
What is the function of a microswitch in the landing gear indication system?
A) To cool the gear bay
B) To open/close an electrical circuit when triggered
C) To apply brake pressure
B) To open/close an electrical circuit when triggered
60
In a microswitch, what happens when the plunger is depressed?
A) The normally closed circuit carries current
B) The movable contact connects to the normally open terminal
C) The switch becomes inactive
B) The movable contact connects to the normally open terminal
61
Why are proximity switches used instead of microswitches in some aircraft systems?
A) They are cheaper
B) They resist contact corrosion from dirt and moisture
C) They consume more power
B) They resist contact corrosion from dirt and moisture
62
How does a reed switch operate?
A) Using a pressure sensor
B) Using a magnet to close the contacts
C) Through mechanical linkage
B) Using a magnet to close the contacts
63
What component in an electronic proximity switch detects the position of the gear component?
A) A laser beam
B) A sensing coil detecting changes in impedance
C) A vibrating sensor
B) A sensing coil detecting changes in impedance
64
How can crew visually verify gear downlock status if the indication system fails?
A) Using external cameras
B) Through floor-mounted viewing panels with alignment marks
C) By checking hydraulic pressure levels
B) Through floor-mounted viewing panels with alignment marks
65
When does the landing gear warning horn typically activate?
A) When the aircraft exceeds 10,000 ft
B) If flaps are extended, throttles are retarded, and gear is not down
C) When speed brakes are deployed
B) If flaps are extended, throttles are retarded, and gear is not down
66
What prevents the landing gear warning horn from being silenced?
A) The throttle is advanced
B) Landing gear is selected down
C) Landing flap is selected with gear not down
C) Landing flap is selected with gear not down
67
What is the primary reason landing must be considered an essential aspect of flight?
A) It ensures high fuel efficiency
B) It affects in-flight communication
C) It is critical for passenger safety
C) It is critical for passenger safety
68
What material are aircraft wheels typically made from?
A) Titanium alloy
B) Aluminium or magnesium alloy
C) Stainless steel
B) Aluminium or magnesium alloy
69
What type of tyre assembly do modern aircraft wheels generally use?
A) Tubed tyre
B) Tubeless tyre
C) Solid rubber tyre
B) Tubeless tyre
70
Where is the O-ring seal located in a wheel assembly with a tubeless tyre?
A) On the tyre tread
B) In the valve stem
C) In the groove between the two half hubs
C) In the groove between the two half hubs
71
What type of bearings are typically used in aircraft wheels?
A) Ball bearings
B) Tapered roller bearings
C) Needle bearings
B) Tapered roller bearings
72
Why is it dangerous to approach overheated aircraft wheels from the side?
A) The tyres may burst or catch fire
B) The bearings could fall out
C) The fusible plugs may overinflate
A) The tyres may burst or catch fire
73
What do fusible plugs do in a tubeless tyre system?
A) Prevent moisture entry
B) Indicate tyre wear
C) Release tyre pressure during overheating
C) Release tyre pressure during overheating
74
Which part of the aircraft typically does NOT have fusible plugs installed?
A) Main gear
B) Tail gear
C) Nose gear
C) Nose gear
75
What shape are the rollers and rings in a tapered roller bearing?
A) Cylindrical
B) Spherical
C) Truncated cones
C) Truncated cones
76
Which of the following is NOT a purpose of aircraft brakes?
A) Assist in mid-air deceleration
B) Keep aircraft stationary on the ground
C) Shorten the landing run
A) Assist in mid-air deceleration
77
What happens to the brake unit during ground braking?
A) It cools down the wheels
B) It generates heat by converting kinetic energy
C) It engages the thrust reversers
B) It generates heat by converting kinetic energy
78
What is the correct fire extinguisher type for brake fires?
A) Water-based
B) Foam-based
C) Dry powder
C) Dry powder
79
What type of brake is typically used on small general aviation aircraft?
A) Multiple-disc
B) Single-disc
C) Carbon-fibre disc
B) Single-disc
80
How many pucks are used in a typical single-disc brake calliper assembly?
A) Four
B) Six
C) Eight
B) Six
81
What allows the single-disc brake to "float" and contact both puck sets?
A) Hydraulic override
B) Friction clutch
C) Lateral movement in key slots
C) Lateral movement in key slots
82
What function does the adjusting pin serve in a single-disc brake?
A) Adds extra braking force
B) Provides a wear indicator
C) Seals hydraulic pressure
B) Provides a wear indicator
83
Dual-disc brakes differ from single-disc brakes by having:
A) An extra calliper
B) A centre carrier between discs
C) Thicker wheel hubs
B) A centre carrier between discs
84
What is the purpose of the torque tube in a multiple-disc brake system?
A) Supply hydraulic fluid
B) Measure temperature
C) Transmit torque from stator discs to the housing
C) Transmit torque from stator discs to the housing
85
What are the components of a heat pack?
A) Bearings and spacers
B) Pressure plate, rotors, stators, and torque tube
C) Hydraulic pump and disc
B) Pressure plate, rotors, stators, and torque tube
86
Compared to steel heat packs, carbon heat packs are:
A) Heavier and cheaper
B) Lighter and more durable
C) More flammable
B) Lighter and more durable
87
Why must rotors and stators be replaced if contaminated with oil or grease?
A) They rust easily
B) It reduces braking efficiency
C) It lowers heat resistance
B) It reduces braking efficiency
88
How are the brake pistons powered?
A) Electrically
B) Mechanically
C) Hydraulically
C) Hydraulically
89
What device allows switching to the alternate braking system in case of hydraulic failure?
A) Pressure regulator
B) Shuttle valve
C) Solenoid
B) Shuttle valve
90
The brake piston automatically adjusts:
A) The hydraulic pressure
B) The brake clearance
C) The rotation speed
B) The brake clearance
91
What indicates the wear level of a heat pack?
A) Colour change in the rotors
B) Wear indicator pin
C) Fluid leakage
B) Wear indicator pin
92
What are the three basic brake actuating systems used in aircraft?
A) Manual, electrical, mechanical
B) Independent, booster, power brake
C) Hydraulic, electric, pneumatic
B) Independent, booster, power brake
93
Which type of aircraft commonly uses independent braking systems?
A) Commercial airliners
B) Military jets
C) Small light aircraft
C) Small light aircraft
94
What does a master cylinder do in an independent braking system?
A) Stores hydraulic fluid in case of emergency
B) Electrically signals brake actuation
C) Creates hydraulic pressure when the rudder pedal is pressed
C) Creates hydraulic pressure when the rudder pedal is pressed
95
Which component in a power brake system meters hydraulic fluid to the brake assemblies?
A) Brake actuator
B) Brake control valve or metering valve
C) Shuttle valve
B) Brake control valve or metering valve
96
What happens in the brake control valve when the rudder or brake pedal is depressed further?
A) The return port opens to release pressure
B) Less hydraulic fluid is sent to the brakes
C) More fluid is allowed through due to the narrowing shape of the slide
C) More fluid is allowed through due to the narrowing shape of the slide
97
What feature allows the brake control valve to provide pedal feel in a power brake system?
A) Shuttle valve
B) Compensating chamber
C) Reservoir
B) Compensating chamber
98
What is the role of the brake valve feel augmentation unit?
A) Adjust brake temperature
B) Provide feedback through mechanical linkage
C) Lock the brakes when parked
B) Provide feedback through mechanical linkage
99
What backup system provides emergency brake power if hydraulic sources fail?
A) Shuttle valve
B) Brake accumulator
C) Booster pump
B) Brake accumulator
100
What does a shuttle valve do in emergency brake systems?
A) Vents excess brake pressure
B) Directs flow from alternate hydraulic sources
C) Controls anti-skid functions
B) Directs flow from alternate hydraulic sources
101
What is the primary purpose of a brake debooster?
A) Increase hydraulic pressure for more braking power
B) Cool brake fluid
C) Reduce hydraulic system pressure to a suitable level for the brakes
C) Reduce hydraulic system pressure to a suitable level for the brakes
102
What equation explains how brake deboosters reduce pressure?
A) Force = Area/Pressure
B) Pressure = Force/Area
C) Volume = Pressure × Time
B) Pressure = Force/Area
103
What additional safety feature does a lockout debooster provide?
A) It cools the hydraulic fluid before it enters the brakes
B) It filters contaminants from the fluid
C) It stops fluid flow in the event of downstream rupture
C) It stops fluid flow in the event of downstream rupture
104
How is the parking brake held in position once set?
A) By continuous electrical pressure
B) By trapping hydraulic fluid using a shut-off valve
C) By applying mechanical locks to the wheels
B) By trapping hydraulic fluid using a shut-off valve
105
What system helps pressurize the brakes when the aircraft is parked?
A) Brake control valve
B) Electrical motor
C) Hydraulic accumulator pressurized by nitrogen
C) Hydraulic accumulator pressurized by nitrogen
106
What does a green arc on the brake temperature display indicate?
A) Brake failure
B) Brake is too cold
C) Brake is above 100 °C
C) Brake is above 100 °C
107
What display system is used on Airbus aircraft to monitor brake temperature?
A) EICAS
B) ECAM
C) FMS
B) ECAM
108
On a brake temperature display, what does an amber color and alert message indicate?
A) Brake temperature is below normal
B) Brake temperature is above 300 °C
C) Brake temperature is within normal limits
B) Brake temperature is above 300 °C
109
What are two possible signs of abnormal brake operation based on temperature readings?
A) Amber numbers and green arcs
B) High temperature (dragging brake) or low temperature (non-functioning brake)
C) White numbers turning red
B) High temperature (dragging brake) or low temperature (non-functioning brake)
110
What is the primary purpose of anti-skid systems on large aircraft?
A) To prevent oversteering on the ground
B) To protect tyres and improve braking efficiency
C) To reduce drag during landing
B) To protect tyres and improve braking efficiency
111
What does a skid indicate in terms of wheel and ground speed?
A) The wheel is turning faster than the aircraft's ground speed
B) The wheel is locked and no longer rotating relative to the ground speed
C) The wheel is spinning freely with no friction
B) The wheel is locked and no longer rotating relative to the ground speed
112
What is the friction state when a tyre experiences 100% skid?
A) Maximum friction
B) Tyre rolls freely
C) Tyre is locked
C) Tyre is locked
113
What effect do wet or icy runways have on tyre-to-ground friction?
A) They increase the friction and reduce skid
B) They decrease the friction and increase skid
C) They have no effect on friction
B) They decrease the friction and increase skid
114
What was the first widely used mechanical/hydraulic anti-skid system?
A) IRS
B) Maxaret
C) BSCU
B) Maxaret
115
In a Maxaret system, what triggers brake release?
A) A pressure drop in the hydraulic system
B) The flywheel spinning faster than the drum and reaching a 60° relative angle
C) The pilot lifting off the brake pedal
B) The flywheel spinning faster than the drum and reaching a 60° relative angle
116
What is the primary advantage of electrohydraulic anti-skid systems over mechanical ones?
A) They use air instead of hydraulics
B) They react to preset deceleration limits
C) They operate independently of wheel speed
B) They react to preset deceleration limits
117
At what speed does an electrohydraulic anti-skid system revert to manual braking?
A) 50 km/h
B) 10 km/h
C) 30 km/h (20 mph)
C) 30 km/h (20 mph)
118
What are the three main components of an anti-skid system?
A) Speed brakes, brake pads, flywheel
B) Wheel speed sensors, control valves, control unit
C) IRS, radar, control cables
B) Wheel speed sensors, control valves, control unit
119
How much skid does the anti-skid system allow under normal operation?
A) 25%
B) 0%
C) 13%
C) 13%
120
What signal indicates an imminent skid in the anti-skid control logic?
A) Positive output signal
B) Negative output signal
C) Equal output signal
B) Negative output signal
121
What type of sensor typically generates an AC signal based on wheel speed?
A) Hydraulic transducer
B) Rotor-stator assembly
C) Piezoelectric sensor
B) Rotor-stator assembly
122
What is the function of the control unit in an anti-skid system?
A) To apply brake pressure continuously
B) To receive wheel sensor inputs and control valve outputs
C) To rotate the tyres during taxi
B) To receive wheel sensor inputs and control valve outputs
123
What causes the anti-skid control valve to reduce brake pressure during a skid?
A) The valve spring fails
B) The pilot releases the brake
C) Differential pressure shifts the valve spool
C) Differential pressure shifts the valve spool
124
How is brake pressure retained when the parking brake is applied?
A) The anti-skid system disables itself permanently
B) A solenoid-operated valve blocks the return line
C) The pilot keeps the pedal pressed
B) A solenoid-operated valve blocks the return line
125
When is anti-skid protection inhibited in an electromechanical braking system?
A) Below 50 knots
B) Above 200 knots
C) Below 25 knots
C) Below 25 knots
126
What triggers brake release in touchdown protection mode?
A) Squat switch indicates airborne status
B) Reverse thrust is engaged
C) Speed brakes are extended
A) Squat switch indicates airborne status
127
What triggers locked wheel protection logic?
A) A wheel rotating 25% slower than its paired wheel
B) Brake pedal is released
C) Brake pressure exceeds limits
A) A wheel rotating 25% slower than its paired wheel
128
What action disables the anti-skid system during take-off?
A) Engaging thrust reversers
B) Activating auto-brakes
C) Gear selector switch input
C) Gear selector switch input
129
When does the auto-brake system activate during landing?
A) When nose gear touches down
B) When speed brakes deploy and throttles are at idle or reverse
C) When flaps are fully extended
B) When speed brakes deploy and throttles are at idle or reverse
130
How is the desired deceleration maintained in the auto-brake system?
A) By the speed brake actuator
B) Through the pilot’s continuous pedal input
C) By comparing IRS deceleration with preselected value
C) By comparing IRS deceleration with preselected value
131
What action deactivates auto-braking during the landing roll?
A) Engine shutdown
B) Deployment of landing gear
C) Pilot pressing the brake pedals
C) Pilot pressing the brake pedals
132
What causes the blue light on the auto-brake selector to flash and go out?
A) Aircraft reaches take-off speed
B) Manual braking overrides auto-brake
C) IRS signal is lost
B) Manual braking overrides auto-brake
133
What effect does reverse thrust have on auto-brake pressure?
A) It increases it to match deceleration
B) It reduces it to maintain selected deceleration
C) It shuts down the anti-skid system
B) It reduces it to maintain selected deceleration
134
How much does each second of delay in brake application increase landing distance?
A) 100 metres
B) 20 metres
C) 60 metres
C) 60 metres
135
Why is it important for aircraft tyres to be in good condition before flight?
A) To reduce fuel consumption
B) To ensure safe take-off and landing
C) To improve passenger comfort
B) To ensure safe take-off and landing
136
Compared to car and lorry tyres, aircraft tyres must withstand:
A) Lower speeds and minimal loads
B) Constant low pressure
C) High loads and high-speed operations
C) High loads and high-speed operations
137
Which of the following is NOT a classification method for aircraft tyres?
A) Tread pattern
B) Type
C) Ply rating
A) Tread pattern
138
How are Type I tyres identified?
A) By rim diameter only
B) By section width and rim diameter
C) By overall diameter only
C) By overall diameter only
139
Type III tyres are typically used on aircraft with landing speeds of:
A) 200 mph or more
B) Less than 160 mph
C) 300 mph
B) Less than 160 mph
140
The tyre identification "6.00 – 6" represents:
A) A 6-inch rim and 6-inch overall diameter
B) A 6-inch section width and 6-inch rim diameter
C) A 6-inch tread depth and 6-inch sidewall height
B) A 6-inch section width and 6-inch rim diameter
141
Type VII tyres are primarily found on:
A) General aviation aircraft
B) Jet aircraft
C) Older fixed gear aircraft
B) Jet aircraft
142
A Type VII tyre marked "26 X 6.6" has:
A) 26-inch rim diameter and 6.6-inch section width
B) 26-inch overall diameter and 6.6-inch section width
C) 26-inch section width and 6.6-inch overall diameter
B) 26-inch overall diameter and 6.6-inch section width
143
Type VIII tyres differ from others by being identified using:
A) Only one number system
B) A three-number system including overall diameter, section width, and rim diameter
C) Letters only
B) A three-number system including overall diameter, section width, and rim diameter
144
What does the “R” in a Type VIII radial tyre designation represent?
A) Rim radius
B) Reinforced sidewall
C) Radial construction
C) Radial construction
145
What does ply rating indicate in an aircraft tyre?
A) Number of fabric layers
B) Load-bearing capacity
C) Tread thickness
B) Load-bearing capacity
146
Which is a key advantage of tubeless tyres over tube-type tyres?
A) Heavier and more durable
B) More prone to tyre creep
C) Slower and more uniform air loss in case of a puncture
C) Slower and more uniform air loss in case of a puncture
147
Bias ply tyres have plies oriented at:
A) 90° to direction of rotation
B) 0° to direction of rotation
C) 30–60° to direction of rotation
C) 30–60° to direction of rotation
148
In radial ply tyres, the carcass plies are arranged:
A) Along the tread
B) Parallel to the tread
C) Perpendicular to the direction of rotation
C) Perpendicular to the direction of rotation
149
Which tyre type typically weighs less and offers lower rolling resistance?
A) Bias
B) Tube-type
C) Radial
C) Radial
150
What is the function of the tyre bead?
A) Provide grip on wet runways
B) Anchor the carcass and transmit load/braking forces
C) Indicate the tyre's balance
B) Anchor the carcass and transmit load/braking forces
151
Which tyre part is specifically designed to resist wear and provide traction?
A) Sidewall
B) Tread
C) Bead
B) Tread
152
What protects the carcass of a tyre from weather and abrasion?
A) Bead
B) Inner liner
C) Sidewall
C) Sidewall
153
The red dot on a tyre indicates:
A) Balance point
B) Maximum tread depth
C) Sidewall ply rating
A) Balance point
154
Awl marks indicate:
A) Retreading history
B) Pressure rating
C) Areas where holes were made to release trapped gas
C) Areas where holes were made to release trapped gas
155
What does the formula √P in hydroplaning speed represent?
A) Load capacity
B) Ply rating
C) Tyre pressure
C) Tyre pressure
156
Which tread is most commonly used on paved surfaces?
A) Diamond
B) Rib
C) Smooth
B) Rib
157
What is a chine tyre designed to do?
A) Improve braking efficiency
B) Reduce rolling resistance
C) Deflect water away from engine intakes
C) Deflect water away from engine intakes
158
1. What is the minimum tread groove depth required for continued use of a ribbed aircraft tyre over more than 25% of the tread circumference?
A) 3 mm (1/8 in)
B) 2 mm (1/16 in)
C) 1 mm (1/32 in)
B) 2 mm (1/16 in)
159
How many times can the majority of aircraft tyres be re-treaded before being scrapped?
A) 5 times
B) 8 times
C) 10 times
C) 10 times
160
What effect does over-inflation have on tyre wear?
A) Increases shoulder wear
B) Accelerates tread wear
C) Causes bulging
B) Accelerates tread wear
161
Under what condition can tyres with certain damage remain in operation temporarily?
A) If approved by the pilot
B) If cleared by ground staff
C) If needed to return to a maintenance base with support from the manufacturer
C) If needed to return to a maintenance base with support from the manufacturer
162
What should be done if a dry braking flat causes unacceptable vibration?
A) Patch the tyre
B) Monitor until next service
C) Replace the tyre
C) Replace the tyre
163
What condition typically results in a "melted" appearance on the tyre surface?
A) Shoulder wear
B) Hydroplaning
C) Chevron cutting
B) Hydroplaning
164
What tyre condition is more likely in H section tyres due to their shape?
A) Lateral scoring
B) Shoulder wear
C) Tread strip
B) Shoulder wear
165
At what point must a tyre with under-inflation be removed, along with its companion tyre on the same axle?
A) Below 90% of operational pressure
B) Below 85% of operational pressure
C) Below 80% of operational pressure
C) Below 80% of operational pressure
166
What type of damage involves separation of tread rubber from the tyre?
A) Tread strip
B) Tread chunking
C) Lateral scoring
A) Tread strip
167
When should a tyre be replaced due to tread chunking?
A) If any tread rib is missing
B) If more than 7 cm² of chunking is visible on a single tread rib
C) If chunking is less than 5 cm²
B) If more than 7 cm² of chunking is visible on a single tread rib
168
What is a cause of open tread joints in tyres?
A) Excessive heat
B) Poor tyre storage
C) Faulty manufacture
C) Faulty manufacture
169
When must a tyre be replaced due to tread groove cracking?
A) When cracks are on the surface
B) If any cords are visible
C) If cracks are less than 1 mm
B) If any cords are visible
170
What can cause lateral scoring on a tyre?
A) Tyre under-inflation
B) Cross-wind landings and tight turns
C) High speeds on smooth runways
B) Cross-wind landings and tight turns
171
When should a tyre be replaced due to chevron cutting?
A) If the tyre is over-inflated
B) If any rubber is discoloured
C) If more than 7 cm² of fabric is visible
C) If more than 7 cm² of fabric is visible
172
What cut damage requires tyre removal?
A) Cuts shorter than 20 mm
B) Cuts with a depth of 25%
C) Cuts extending into casing plies
C) Cuts extending into casing plies
173
What is the appropriate action if a bulge is found in a tyre?
A) Mark and monitor
B) Reduce pressure
C) Replace tyre immediately
C) Replace tyre immediately
174
When must a tyre be replaced due to sidewall cracking?
A) If cracks are less than 1 mm deep
B) If any casing cords are exposed
C) If cracking is only cosmetic
B) If any casing cords are exposed
175
When must a tyre be replaced due to sidewall undulation?
A) If undulation depth exceeds 3 mm
B) If it spans more than 50 mm
C) If located near the wheel
A) If undulation depth exceeds 3 mm
176
What must be done if a tyre burst occurs?
A) Repair the tyre
B) Replace only the burst tyre
C) Replace the burst tyre and any on the same axle
C) Replace the burst tyre and any on the same axle
177
Which of the following indicates damage from high brake heat?
A) Softened shoulder rubber
B) Blue bead rubber
C) Sidewall cracking
B) Blue bead rubber
178
What should be done if a tyre has been exposed to fuel contamination for over 48 hours?
A) Wash and reuse
B) Send to Dunlop for repair
C) Remove the tyre
C) Remove the tyre
179
What is "tyre creep"?
A) Gradual air leakage
B) Circumferential movement of the tyre on the rim
C) Sidewall expansion during storage
B) Circumferential movement of the tyre on the rim
180
How should stored tyres be positioned for best practice?
A) Flat on the floor
B) Vertically on racks with tubed supports
C) Hung by the valve stem
B) Vertically on racks with tubed supports
181
What is the recommended inflation pressure for assemblies stored for extended periods?
A) 70 – 100 kPa
B) 140 – 210 kPa
C) 250 – 300 kPa
B) 140 – 210 kPa
182
What is the primary function of the nose wheel steering (NWS) system in an aircraft?
A) To control engine thrust during flight
B) To steer the aircraft during ground operations
C) To balance the aircraft in turbulent air
B) To steer the aircraft during ground operations
183
How do simply designed aircraft with caster nose wheels achieve directional control during taxiing?
A) Nose wheel steering from the flight deck
B) Electronic rudder control
C) Differential braking
C) Differential braking
184
In differential braking, how is a right turn achieved?
A) By pressing both brake pedals simultaneously
B) By operating only the left brake pedal
C) By operating only the right brake pedal
C) By operating only the right brake pedal
185
Why must pilots be cautious when using differential braking at high speeds?
A) It may cause tire deflation
B) It results in delayed directional response
C) It causes an instantaneous change of direction
C) It causes an instantaneous change of direction
186
How is nose wheel steering typically controlled in small aircraft?
A) With a joystick on the flight deck
B) Through rudder pedal mechanical linkages
C) Using hydraulic metering valves
B) Through rudder pedal mechanical linkages
187
What is commonly used in large aircraft to control nose wheel steering from the flight deck?
A) Brake pedals
B) A nose wheel tiller or joystick
C) A lever near the landing gear
B) A nose wheel tiller or joystick
188
What is the function of the metering valve in a nose wheel steering system?
A) It cools hydraulic fluid
B) It directs hydraulic pressure to actuators
C) It measures tire pressure
B) It directs hydraulic pressure to actuators
189
What component keeps hydraulic fluid in the steering system pressurised at all times?
A) The rudder pedal
B) The accumulator and relief valve or compensator
C) The centring cam
B) The accumulator and relief valve or compensator
190
What mechanism returns the metering valve to a neutral position after a steering angle is achieved?
A) Shimmy damper
B) Nose wheel spindle
C) Follow-up mechanism
C) Follow-up mechanism
191
What is the purpose of safety valves in the NWS system?
A) To activate shimmy dampers
B) To reduce hydraulic system weight
C) To relieve pressure during hydraulic failure
C) To relieve pressure during hydraulic failure
192
In the hydraulic system, what causes cylinder 'A' to extend and turn the nose gear?
A) Cable tension
B) Brake pedal input
C) Pressure from port 'A'
C) Pressure from port 'A'
193
What is the role of the compensator in the steering system?
A) It measures steering angles
B) It acts as a secondary metering valve
C) It maintains system pressure and allows return fluid flow
C) It maintains system pressure and allows return fluid flow
194
What condition opens the compensator poppet valve?
A) External air venting
B) When spring compression pressure is reached
C) When brake pedals are pressed
B) When spring compression pressure is reached
195
What is the primary function of shimmy dampers?
A) To assist in differential braking
B) To prevent structural damage during take-off
C) To damp rapid oscillations in nose gear
C) To damp rapid oscillations in nose gear
196
Which of the following does not contribute to nose wheel shimmy?
A) Over-inflated tyres
B) High steering hydraulic pressure
C) Worn attachment fittings
B) High steering hydraulic pressure
197
How does a shimmy damper work?
A) By rotating the nose wheel slowly
B) By blocking hydraulic fluid flow
C) By forcing hydraulic fluid through a small orifice in a piston
C) By forcing hydraulic fluid through a small orifice in a piston
198
What mechanism is used to align the nose gear before retraction?
A) Steering joystick
B) Centreing cams
C) Brake pedal tension
B) Centreing cams
199
What device sometimes helps straighten small aircraft nose wheels during retraction?
A) Air vents
B) Torque links
C) External roller or guide pin and ramp system
C) External roller or guide pin and ramp system
200
Why do some aircraft incorporate main gear steering systems?
A) To reduce cockpit workload
B) To reduce tyre scrub and turning radius
C) To balance engine torque
B) To reduce tyre scrub and turning radius
201
When does the main gear steering system typically activate?
A) At high altitudes
B) When the nose gear is fully retracted
C) When the nose gear reaches a specific turn angle
C) When the nose gear reaches a specific turn angle
202
What must be done to the NWS system during towing?
A) Increase hydraulic pressure
B) Keep metering valves closed
C) Unpressurise or isolate the system
C) Unpressurise or isolate the system
203
What is the purpose of inserting a towing safety pin during towing?
A) To activate nose gear centring cams
B) To equalise pressure in the actuator pistons
C) To disconnect the hydraulic return line
B) To equalise pressure in the actuator pistons
204
What could happen if the NWS system is pressurised during towing without the tow pin inserted?
A) Improved steering performance
B) Reverse loads on the tow bar causing potential damage
C) Equalised hydraulic pressure
B) Reverse loads on the tow bar causing potential damage
205
If the towing turn angle exceeds limits, what action is necessary?
A) Shut off the hydraulic system
B) Insert an air vent
C) Disconnect the torsion links
C) Disconnect the torsion links
206
What is the purpose of air/ground sensing in an aircraft with a retractable undercarriage?
A) To monitor the fuel levels during flight
B) To prevent various systems from operating inappropriately on the ground or during flight
C) To control engine thrust
B) To prevent various systems from operating inappropriately on the ground or during flight
207
Where are the micro-switches or proximity sensors that signal the aircraft’s Weight On Wheels (WOW) typically located?
A) On the tail section of the aircraft
B) On the main and nose gear shock struts
C) On the wing structure
B) On the main and nose gear shock struts
208
What is another term for the micro-switches that detect Weight On Wheels (WOW)?
A) Proximity switches
B) Squat switches
C) Load sensors
B) Squat switches
209
What does the air/ground sensing system assist with in aircraft operations?
A) It regulates cabin temperature
B) It ensures the correct operation of various systems based on whether the aircraft is on the ground or in the air
C) It controls engine output
B) It ensures the correct operation of various systems based on whether the aircraft is on the ground or in the air
210
How does a basic WOW system work on modern transport aircraft?
A) The proximity sensors detect airspeed
B) The sensors detect whether the aircraft is in the air or on the ground based on the position of the gear strut
C) The sensors monitor fuel levels during flight
B) The sensors detect whether the aircraft is in the air or on the ground based on the position of the gear strut
211
In the air/ground sensing system, how do proximity sensors determine if the aircraft is on the ground?
A) By monitoring the aircraft’s altitude
B) By detecting the distance between the sensor and the target based on the gear strut’s compression or extension
C) By measuring cabin pressure
B) By detecting the distance between the sensor and the target based on the gear strut’s compression or extension
212
What additional factor is monitored in aircraft with 4 or 6-wheel main landing gear for air/ground sensing?
A) Engine thrust levels
B) Bogie position (tilt or not tilt)
C) Hydraulic fluid pressure
B) Bogie position (tilt or not tilt)
213
What is the role of load sensors in some air/ground sensing systems?
A) They monitor the aircraft’s fuel consumption
B) They capture the weight of the aircraft when it is on the ground
C) They measure airspeed during flight
B) They capture the weight of the aircraft when it is on the ground
214
How do strain gauge load sensors work in the air/ground sensing system?
A) They measure the temperature of the landing gear
B) They detect the weight of the aircraft by monitoring changes in distance between two parts of the sensor
C) They detect fuel consumption during flight
B) They detect the weight of the aircraft by monitoring changes in distance between two parts of the sensor
215
What type of signal is sent to the WOW cards by the load sensors?
A) Digital
B) Analog
C) Radio frequency
B) Analog
216
What must be done when replacing a sensor in the air/ground sensing system?
A) The sensors must be cleaned
B) The sensor must be calibrated
C) The sensor must be powered off
B) The sensor must be calibrated
217
Why must electrostatic sensitive material precautions be observed when handling WOW cards?
A) To prevent damage to the aircraft's engines
B) To avoid damage to the WOW cards due to electrostatic discharge
C) To ensure the sensors function properly
B) To avoid damage to the WOW cards due to electrostatic discharge
218
What additional information can be displayed on the flight deck regarding air/ground sensing?
A) Weight distribution across the aircraft
B) Air/ground system messages and load sensor outputs
C) The status of engine performance
B) Air/ground system messages and load sensor outputs
219
What is the purpose of the landing gear maintenance display on the flight deck?
A) To control the aircraft's landing gear speed
B) To display air/ground system status and initiate testing
C) To adjust fuel levels during take-off
B) To display air/ground system status and initiate testing
