The air cycle cooling system produces cold air by:
extracting heat energy across a compressor. passing air through cooling coils that contain a refrigerant. extracting heat energy across an expansion turbine.
Unloading valves are used with many engine-driven hydraulic pumps to:
dampen out pressure surges. relieve the pump pressure. relieve system pressure.
Grounding is electrically connecting a conductive object to the primary structure. One purpose of grounding is to:
prevent current return paths. allow static charge accumulation. prevent development of radio frequency potentials.
Where should the flux be applied when oxyacetylene welding aluminum?
Painted only on the surface to be welded. Painted on the surface to be welded and applied to the welding rod. Applied only to the welding rod.
Which of the following need not be considered when determining minimum rivet spacing?
Rivet diameter. Rivet length. Type of material being riveted.
The basic difference between an autosyn and a magnesyn indicating system is the:
rotor. transmitter. receiver.
Why are jet fuels more susceptible to water contamination than aviation gasoline?
Jet fuel has a higher viscosity than gasoline. Jet fuel is lighter than gasoline; therefore, water is more easily suspended. Condensation is greater because of the higher volatility of jet fuels.
What is the condition of the refrigerant as it leaves the condenser of a vapor-cycle cooling system?
Low-pressure liquid. High-pressure liquid. High-pressure vapor.
Which of the following should be accomplished in the installation of aircraft wiring?
Support the bundle to structure and/or solid fluid lines to prevent chafing damage. Provide adequate slack in the wire bundle to compensate for large changes in temperature. Locate the bundle above flammable fluid lines and securely clamp to structure.
Hot compressor bleed air operates the conditioned air system on some turbine aircraft, how is cold air supplied?
By the air cycle machine turbine. By the flow control unit. By the ram cycle cooling unit.
If the liquid level gauge in a vapor-cycle cooling system indicates a low freon charge, the system should:
be operated and a pressure check performed. be operated for a period of time to reach a stable condition and then the freon level rechecked. not be operated until freon and oil have been added.
Glue deterioration in wood aircraft structure is indicated:
when a joint has separated and the glue surface shows only the imprint of the wood with no wood fibers clinging to the glue. when a joint has separated and the glue surface shows pieces of wood and/or wood fibers clinging to the glue. by any joint separation.
Heat exchanger cooling units are required in some aircraft hydraulic systems because of:
fluid flammability. high pressures and high rates of fluid flow. the high heat generated from braking.
Which is a characteristic of synthetic base hydraulic fluid?
Low moisture retention. High flash point. Low flash point.
If it is determined that spongy brake action is not caused by air in the brake system, what is the next most likely cause?
Worn brake lining. Internal leakage in the master cylinder. Deteriorated flexible hoses.
(1) Gas-turbine-engine fuel systems are very susceptible to the formation of ice in the fuel filters. (2) A fuel heater operates as a heat exchanger to warm the fuel. Regarding the above statements,
only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
What is the principal advantage of the series wound dc motor?
High starting torque. Suitable for constant speed use. Low starting torque.
What condition would most likely cause excessive fluctuation of the pressure gauge when the hydraulic pump is operating?
Accumulator air pressure low. Inadequate supply of fluid. System relief valve sticking closed.
What is the purpose of a mixing valve in a compressor bleed air air-conditioning system?
Control the supply of hot, cool, and cold air. Distribute conditioned air evenly to all parts of the cabin. Combine ram air with conditioned air.
What will occur if an aircraft attitude is changed by its autopilot system in order to correct for an error and the involved control surfaces are returned to streamline by the time the aircraft has reached its correct position?
Overshoot and oscillation. Undershoot and oscillation. Normal operation.
In which control element of an autopilot system is an attitude indicator?
Command. Sensing. Input.
The major advantages of alternating current (AC) over direct current (DC) is the fact that its current and voltage can easily be increased or decreased:
by means of a inverter. by means of a rectifier. by means of a transformer.
To what depth is the mica insulation between the commutator bars of a dc generator undercut?
One half the width of the mica. Equal to twice the width of the mica. Equal to the width of the mica.
The air that is expended and no longer needed when an actuating unit is operated in a pneumatic system is:
exhausted or dumped, usually overboard. returned to the compressor. charged or pressurized for use during the next operating cycle.
The general rule for finding the proper rivet diameter is:
three times the thickness of the materials to be joined. two times the rivet length. three times the thickness of the thickest sheet.
When swinging a magnetic compass, the compensators are adjusted to correct for:
magnetic influence deviation. compass card oscillations. magnetic variations.
Which type of dc generator is not used as an airplane generator?
Externally grounded. Series wound. Compound wound.
If any one generator in a 24-volt do system shows low voltage, the most likely cause is:
an out-of-adjustment voltage regulator. shorted or grounded wiring. a defective reverse current cutout relay.
Teflon hose that has developed a permanent set from being exposed to high pressure or temperature should:
not be straightened or bent further. not be reinstalled once removed. be immediately replaced.
What type of remote-reading fuel quantity indicating system has several probes installed in each fuel tank?
Electromechanical. Electronic. Direct reading.
What action, if any, should be taken when there is a difference of more than 5 pounds of air pressure in tires mounted as duals?
Replace both tires. Correct the discrepancy and enter in logbook. Replace the tire with the lowest pressure.
Mild steel rivets are used for riveting:
nickel-steel parts. magnesium parts. steel parts.
(1) Use solder to attach bonding jumpers on radio equipment. (2) Radio equipment is bonded to the aircraft in order to provide a low-impedance ground and to minimize radio interference from static electrical charges.
Regarding the above statements,
only No. 1 is true. both No. 1 and No. 2 are true. only No. 2 is true.
Fiberglass damage that extends completely through a laminated sandwich structure:
may be repaired. must be filled with resin to eliminate dangerous stress concentrations. may be filled with putty which is compatible with resin.
Why should a chemical rain repellent not be used on a dry windshield?
It will etch the glass. It will restrict visibility. It will cause glass crazing.
When installing a DME antenna, it should be aligned with the:
null position. angle of incidence. centerline on the airplane.
If a pilot reports that an airplane flies left wing heavy, this condition may be corrected by:
increasing the angle of incidence of the left wing, or decreasing the angle of incidence of the right wing, or both. increasing the dihedral angle of the left wing, or decreasing the dihedral angle of the right wing, or both. increasing the dihedral angle of the left wing, or decreasing the dihedral angle of the right wing, or both.
When testing the strength of Grade A cotton fabric covering an aircraft that requires only intermediate grade, the minimum acceptable strength the fabric must have is:
70 percent of its original strength. 70 percent of the original strength for intermediate fabric. 56 pounds per inch warp and fill.
Cherrymax and Olympic-Lok rivets:
utilize a rivet gun, special rivet set, and bucking bar for installation. utilize a pulling tool for installation. may be installed with ordinary hand tools.
Differential control on an aileron system means that:
the down travel is more than the up travel. the up travel is more than the down travel. one aileron on one wing travels further up than the aileron on the opposite wing to adjust for wash-in and wash-out.
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