Test 1 Jet trasnportation
In a manual flying control system the control inputs to the primary control surface
1. Are reversible 2. Are instinctive for the movement required
Which of the following statements will produce the shortest landing run
1. Crossing the threshold at the correct height and speed 2. Applying full anti-skid braking as quickly as possible after touchdown 3. Application of reverse thrust as early as possible in the landing run 4. Deployment of the lift dumpers/speed brakes as early as possible in the landing run
A fail-safe structure :
1. Has a programmed inspection cycle to detect and rectify faults. 2. Is secondary structure of no structural significance
The advantages of a cable control are
1. Light, very good strength to weight ratio 2. Easy to route through the aircraft 3. Less prone to impact damage 4. Takes up less volume 5. Less bolted joints
To prevent cavitation of the pump a hydraulic reservoir may be
1. Pressurized 2. Bootstrapped 3. Above the pump
In a cable control system cables are tensioned to
1. Remove backlash from the control linkage 2. Provide positive action in both directions 3. Compensate for temperature variations
Safe life structure
1. Should not fail until a predicted number of fatigue cycles has been achieved 2. Has a programmed inspection cycle to detect and rectify faults 3. Is changed before its predicted life is reached
The functions of an accumulator is to
1. Store fluid under fluid 2. Dampen pressure fluctuations 3. Allow for fluid expansion 4. Allow for thermal expansion 5. Prolong the period between pump cut-in and cut-out 6. Provide an emergency reserve of pressure in the event of pump failure
Creep (slippage)
Alignment can rip out the inflation value on tubed tyres, and deflate the tyre
A nose wheel steering control system
Allows the nose wheel to castor within preset limits about the neutral position
A shuttle valve
Allows two supply sources to operate one unit
Aircraft structures consists mainly of
Aluminium alloy sheets and rivets with titanium or steel materials at points requiring high strength
A main system hydraulic pump
Always need a positive fluid supply in order to prevent cavitation
Pascal's law states that
Applied force acts equally in all directions
Landing gear ground locking pins are
Removed prior to flight and stowed on the aircraft where they are visible to the crew
When the hydraulic system pressure is released
Reservoir fluid contents will rise if reservoir is lower than other components in the system
The tyre pressure are checked after a long taxi to the ramp following landing. The pressure will have
Risen by 10% of their original weight-on-wheels value
The purpose of an accumulator is to
Store fluid under pressure
Flight deck windows are constructed from
Strengthened glass with shock absorbing clear vinyl inter layers and rubber pressure seals
The hydraulic fluid is changed, but the wrong fluid is replaced. This would lead to
System failure from leaks and blocked filters, high temperature and possible corrosion
The purpose of reservoir is
To allow for fluid displacements, small leaks, thermal expansion and contents monitoring
The purpose of pulleys wheels in cable control system is
To change the direction of the control cable
The primary purpose of a hydraulic reservoir is
To compensate for leaks, displacement and expansion
Case drain filters are
To enable pump lubricating fluid to be used to monitor pump condition
A separator in an accumulator
To isolate the gas form the fluid
The purpose of fairleads in a cable control system is to
To keep the cable straight and clear of structure
The purpose of the secondary stops in a control system is
To limit control surface range in the event of primary stop failure
Purpose of stringers
To prevent buckling and bending by supporting and stiffening the skin
The purpose of the primary stops in a control system is
To set the range of movement of the control surface
Purpose of wing ribs
To shape the wing and support the skin
The purpose of the wing main spar
To withstand bending and torsional loads
The formula which gives the minimum speed (Vp) at which aquaplaning may occur is
VP = 9 × √P where P is psi and VP is in knots
A hydraulic lock occurs
When flow is stopped and the actuator is not able to move
Different diameter actuators supplied with the same pressure at same rate
Exert different forces
With a one way check valve (NRV)
Flow stops when input pressure is less than output pressure
The anti-skid system would be used
For both take off and landing runs
To prevent scrubbing the tyres while taxiing, you should
Turn no sharper than the minimum specified radius
A shuttle valve will allow
Two independent pressure sources to operate a system/ component
A restrictor valve is physically fitted in the
U/C up line and flap up line
A force of 1500 N is applied to a piston of area 0.002 m² and generates a force of----(1)------non a piston of area 0.003 m². The pressure generated is -----(2)----- and, if the smaller piston moves 0.025 m, the work done is -----(3)------.
(1) 2250 N (2) 750 000 Pa (3) 37.5 J
An aircraft has a tyre pressure of 225 psi, its minimum aquaplaning speed will be
135 knots
A pre charge pressure of 100 bar of gas is shown on the accumulator gauge. The system is then pressurized to 1500 bar, so the accumulator will read
1500 bar
When inlfating a tyre fitted to an aircraft, the tyre pressure reading on the gauge should be modified by
4 psi
A constant pressure hydraulic pump is governed by
A control piston
In the case of a failure of a cut-out valve:
A full flow relieve valve is fitted down stream of it
Station numbers (Stn) and water lines (WL) are
A means of locating airframe structure and components
A likely cause of nose wheel shimmy is
A torque link is worn or damaged
With air in the hydraulic system you would
Bleed the air out of the system
How can wing bending moments be reduced in flight
By using aileron 'up-float' and keeping the center section fuel tanks full for as long as possible
With a hyd lock there is
No flow, jack is stationary
Creep (slippage)
Can be measured by painting marks on the tyre and wheel rim
The specification of hydraulic fluids, mineral, vegetable or ester based is
Cannot be distinguished by color alone
A non-return valve
Closes if inlet pressure ceases
The purpose of reservoir is to
Compensate for small leaks, expansion and jack displacement
A restrictor valve
Controls the rate of movement of a service
The movement of the gear on lowering is normally damped to
Counteract the force of gravity which would bring the gear down too fast
Hydraulic pressure in a closed system
Does not vary with pipe diameter
A hydraulic gear extension/retraction mechanism consists of sequence valves, uplocks and
Downlocks
The best extinguishant to use on a wheel or brake fire is
Dry powder
The contents of the hydraulic fluid reservoir are checked. They indicate that the reservoir is at the full level. The system is then pressurized. The contents level will
Fall below the "full" mark
A hand pump is usually fitted for
Ground servicing purposes
A damage tolerant structure
Has degree of structural strength redundancy spread over a large are
The primary purpose of the fuselage is to
House the crew and payload
Skydrol hydraulic fluid can be used to replenish
Hydraulic system that have butyl rubber seals only
Hydraulic thermal relief valves are fitted
In isolated lines only to relieve excess pressure caused by temperature rises
The most likely cause of brake unit dragging is
Incorrect operation of the adjuster assemblies
Control surface flutter
Is a destructive vibration that must be damped out within the flight envelope
A torsion box
Is a structure formed between the wing spars, skin and ribs to resist bending and twisting loads
Hammering in system
Is detrimental to the system
The pressure filter in a hydraulic system
Is fitted down stream of the pump
Skydrol hydraulic fluid
Is flame resistant but is harmful to skin, eyes and some paints
The skin of modern pressurized aircraft
Is primary load bearing structure carrying much of the structural loads
A cantilever wing
Is supported at one end only with no external bracing
The ply rating of a tyre
Is the index of the tyre strength
A pressure maintaining or priority valve
Is used to ensure available pressure is directed to essential services
A lightening hole in a rib
Lightens and stiffens the structure
Oil is used in an oleo strut to
Limit the speed of compression of the strut
Control surface flutter is minimized by
Mass balance of the control surface
A variable displacement pump on system startup will be at
Maximum stroke
A high pressure hydraulic pump
Needs a positive fluid supply
The seal materials used with hydraulic fluids to DEF/STAN 91-48 and SKYDROL 700 specification are respectively:
Neoprene and butyl
In the construction of airframes the primary purpose of frames or formers is to
Oppose hoop stresses and provide shape and form to the fuselage
The purpose of a hydraulic fuse is to
Prevent total loss of system fluid if the brake pipeline is ruptured
Inadvertent retraction of the landing gear on the ground is
Prevented by the ground/air logic system
An ACOV will
Provide an idling circuit when the accumulator is fully charged
In a cable control system the cables are mounted in pairs to
Provide tension on the turnbuckles
Accumulator floating piston
Provides a seal between the gas and fluid
Low gas pressure in accumulator causes
Rapid pressure fluctuations while system is operating
Def. Stan 91/48 is ___ and is ___ based
Red, mineral
A relief valve
Relieves at its designed pressure
In an operating hydraulic actuator the pressure of the fluid will be
The same at all points
Tyre wear
Taxiing at least less than 40 kph
To roll the aircraft to the right
The aileron control is move to the right, the right aileron goes up and the left one down
The pressure needed to operate the wheel brakes on a large aircraft comes from
The aircraft main hydraulic system
The most likely cause of brake fade is
The brake pads overheating
In an enclosed system pressure is felt
The same both ends between the piston and the cylinder
Hydraulic pressure of 3000 Pa is applied to an actuator, the piston area of which is 0.02 m^2 and the same pressure is exerted on actuator whose area is 0.04 m^2:
The smaller jack will exert a force of 60 N and the larger 120 N
The airfarme structure must remain substantially intact after experiencing
The design limit load times a 1.5 factor of safety
A force of 100 N is applied to 2 separate jacks, the area of one is 0.02 m^2 and the other is 0.04 m^s
The smaller jack will exert a pressure of 5000 Pa and the larger 2500 Pa
The pressure gauge of a hydraulic system provides information regarding the pressure of
The hydraulic fluid in the system
The Maximum Zero Fuel Mass (MZFM) of an aircraft is
The maximum permissible mass of an aircraft with no usable fuel
To yaw the aircraft to the right
The right rudder pedal is pushed forward and the rudder moves to the right
The nose wheel assembly must be centered before retraction because
There is limited space in the nose wheel bay
At an aircraft taxiing speed of 10 mph the anti-skid braking system is
inoperative
