Oral Flashcards
Why is it important that traces of welding Flux be removed after a piece of aluminum or magnesium is welded?
Welding Flux is corrosive and must be removed to keep the metal from corroding
What takes up the shock of the landing impact in the oleo shock strut
The metered transfer of oil from one compartment to another inside the shock
What takes up the taxi shocks in an oleo shock strut
Compressed air
How much oil should be put into an oleo shock strut
Deflate the strut completely, remove the filter plug and fill the strut with oil to the level of the fuller plug
What should be done to Hydraulic brakes when the pedal has a spongy feel
The spongy feel is cause by air in the brake , the brakes should be bleed of this air
How is the correct amount of air in an oleo strut determined
By the amount the strut extends out of the cylinder when the weight of the aircraft is on it
What is the purpose of a compensator port in the master cylinder of aircraft brakes
The compensator port in the master cylinder opens the brake reservoir to the wheel cylinder when the brakes are off. This prevents pressure building up in the brake lines and causing the brakes to drag
What are the two basic types of hydraulic fluid that are used in modern aircraft
Mineral base fluid and phosphate Ester base fluid
What does unloading valve do in a hydraulic system
The unloading valve, or pressure,controls systems pressure by shifting the pump outlet fluid from the pressurized systems back into the reservoir when the systems pressure is high enough. The fluid cirulates with very little load on the pump until the system pressure drops to the regulator kick-in valve. The pump then forces fluid into the system until the pressure builds back up to the regulator kickoff valve
What is the purpose of an orifice check valve in an aircraft hydraulic system
An orifice check valve allows full flow of fluid in one direction through the valve but restricts it in the opposite direction
What is meant by a single action hydraulic actuation cylinder
A linear actuation cylinder that uses Hydraulic fluid under pressure to move the piston in only one direction. The piston is returned by a spring
What kind of device is used to control the speed of movement of the position in a pneumatic actuator
A variable orifice
What is the difference between an open center selector valve and a close center valve
Open center selector valves are installed in series with each other, and the hydraulic fluid flows through their center when no component is being actuated.
Closed center selector valve are installed in parallel with each other they direct fluid under pressure to one side if the actuator and fluid from the other side of the actuator to the system return manifold. In the off position, they trap fluid in the lines between Tha. Alve a d the actuator
What is used to flush a hydraulic system that sues mineral base hydraulic fluid
Alcohol
Where can you find the type of hydraulic fluid that is required for particular aircraft
In the maintenance manual of the aircraft. This information is also on a placard on the system reservoir
What is used to remove phosphate Ester base hydraulic fluid from aircraft tires
Soap and water
How is the heat removed from an aircraft cabin with a vapor cycle air conditioning system
The cabin heat is absorbed by the refrigerant in the evaporator, and it is carried outside the aircraft where it is given up to the outside air in the condenser
What produces the cool air in a vapor cycle air condition system
Warm cabin air is blown across the evaporator, where its heat is transferred into the refrigerant. The air that leaves the evaporator is cool
What must air cycle air conditioning systems incorporate a water separator
The rapid cooling of the air in the expansion Turbine causes moisture to condense in the from of fog. The moisture is trapped in the moisture separator before the air is released into the cabin
What is used as refrigerant in a vapor cycle air conditioning system
A freon-type liquid refrigerant know as Refrigerant 12, or the more environmentally friendly R-134a
What instrument in an aircraft are connected to the static system
The airspeed indicator, the vertical speed indicator, and the altimeter
What is the significance of a red radial line on the dial of an aircraft instrument?
A red radial line marks a never-exceed condition.
What is the significance of a yellow arc on the dial of an aircraft instrument?
A yellow arc marks a caution range of operation
What is the significance of a white arc on the dial of an airspeed indicator?
A white arc on an airspeed indicator indicates the airspeeds at which the flaps may be lowered.
What error is corrected when an aircraft compass is swung
Deviation error
What fluid is used in an aircraft magnetic compass
A special water-clear fluid that is similar to kerosene
What is the maximum amount to deviation error that is allowed when a magnetic compass is install in an aircraft
10 degree
What are two types of fuel cells that are used in modern aircraft?
Integral fuel cells (cells that are a sealed-off portion of the structure) and bladder-type cells
Why are fuel tanks divided into compartments or have baffles installed in them?
The compartments or baffles keep the fuel from surging back and forth as the
aircraft changes its attitude in flight.
What is meant by an integral fuel cell?
part of the structure in which all of the seams and joints are sealed so they will be
fuel tight. The structure itself then becomes the fuel tank.
Where are fuel system strainers located?
One strainer is located in the outlet to the tank, and the main strainer is located in
the fuel line between the outlet of the fuel tank and the inlet to the fuel metering
device.
What are three uses of a centrifugal booster pump that is installed in an aircraft fuel
tank?
Booster pumps are used to produce fuel pressure for starting the engine, to keep the
fuel from vapor locking at high altitude, and to transfer fuel from one tank to
another.
What is meant by a compensated engine-driven fuel pump?
An engine-driven fuel pump whose pressure relief valve is acted upon by the pressure
of the atmosphere. A compensated pump varies its outlet fuel pressure so it will stay
a constant amount higher than the pressure of the air that is entering the carburetor.
Why do engine-driven fuel pumps have a bypass valve in them?
The bypass valve allows fuel from the booster pump to flow around the engine-
driven pump mechanism for starting the engine and to supply the engine with fuel if
the engine-driven pump should fail
What is the purpose of a drip gage in the fuel tank of a large aircraft?
drip gage allows a mechanic to check the fuel level in a tank from the bottom of
the tank
What is the maximum number of wires that should be connected to any single stud in a
terminal strip?
Four
Why are solderless splices usually better than soldered splices in the wiring of an
aircraft electrical system?
Soldered joints are usually stiff and vibration can harden the wire and cause it to break. Solderless splices are designed to keep the joint flexible, so vibration cannot
cause the wire to break.
Why must a switch be derated if it is used in a circuit that supplies incandescent lamps?
The high inrush current caused by the low resistance of the cold filaments requires
that the switches be derated
Which species of wood is considered to be the standard when comparing other woods use in air craft structure
Sitka spruce
What is the correct repair to a wood aircraft wing spar if the the wing attach bolt holes in a spar are elongated
Splice in a new section of the spar and drill new holes
Why is retarder used in dope when the dope is being sprayed in humid conditions
The retarded slows the drying of the dope and keep it from blushing
