One purpose of the freewheeling unit required between the engine and the helicopter transmission is to
automatically disengage the rotor from the engine in case of an engine failure. disconnect the rotor from the engine to relieve the starter load. permit practice of auto rotation landings.
If an aircraft's transparent plastic enclosures exhibit fine cracks which may extend in a network over or under the surface or through the plastic, the plastic is said to be:
hazing. brinelling. crazing.
Hydraulic system thermal relief valves are set to open at a:
lower pressure than the system relief valve. higher pressure than the system relief valve. lower pressure than the system pressure regulator.
The presence of fuel stains around a fuel nozzle would indicate:
too much fuel pressure. excessive airflow across the venturi. clogged fuel nozzle.
During inspection of the terminal strips of an aircraft electrical system, it should be determined that:
only locknuts have been used for terminal attachment to the studs. the terminal studs are anchored against rotation. only plain nuts and lockwashers have been used for terminal attachment to the studs.
The vapor pressure of aviation gasoline is:
lower than the vapor pressure of automotive gasoline. higher than the vapor pressure of automotive gasoline. approximately 20 PSI at 100°F.
If it is necessary to adjust several pressure regulating valves in a hydraulic system, what particular sequence, if any, should be followed?
Units most distant from the hydraulic pump should be adjusted first. Units with the highest pressure settings are adjusted first. Units are independent of each other, and therefore, no particular sequence is necessary.
A voltage regulator controls generator output by:
introducing a resistance in generator-to-battery lead in the event of overload. shorting out field coil in the event of overload. varying current flow to generator field coil.
The lubber line on a directional gyro is used to:
represent the nose of the aircraft. align the instrument glass in the case. represent the wings of the aircraft.
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.
If a fire-extinguisher cartridge is removed from a discharge valve for any reason, it:
must be pressure checked. is recommended that the cartridge be used only on the original discharge valve assembly. cannot be used again.
Hydraulic fluid filtering elements constructed of porous paper are normally:
cleaned and reused. discarded at regular intervals and replaced with new filtering elements. not approved for use in certificated aircraft.
For use in pressurized aircraft, which is generally the least complicated and requires the least maintenance?
Chemical oxygen generator systems. High-pressure oxygen systems. Low-pressure oxygen systems.
(1) An antiskid system is designed to apply enough force to operate just below the skid point. (2) A warning lamp lights in the cockpit when the antiskid system is turned off or if there is a system failure. Regarding the above statements,
only No. 1 is true. only No. 2 is true. both No. 1 and No. 2 are true.
What method would be used to check for internal leakage of a fuel valve without removing the valve from the aircraft?
Place the valve in the OFF position, drain the strainer bowl, and with boost pump on, watch to see if fuel flows to the strainer bowl. Remove fuel cap(s), turn boost pump(s) on, and watch for bubbling in the tanks. Apply regulated air pressure on the downstream side of the fuel pump and listen for air passing through the valve.
The shielding gases generally used in the Gas Tungsten Arc (GTA) welding of aluminum consist of:
a mixture of nitrogen and carbon dioxide. nitrogen or hydrogen, or a mixture of nitrogen and hydrogen. helium or argon, or a mixture of helium and argon.
Which of the following copper electrical cable sizes should be selected to replace a No. 6 aluminum electrical cable?
No. 4. No. 6. No. 8.
When used in fire-detection systems having a single indicator light, thermal switches are wired in:
parallel with each other and in series with the light. series with each other and the light. series with each other and parallel with the light.
What safety device is actuated by the compression and extension of a landing gear strut?
Uplock switch. Downlock switch. Ground safety switch.
Which valve installed in a hydraulic system will have the highest pressure setting?
Pressure regulator valve. Main relief valve. Thermal relief valve.
Under certain conditions, type A rivets are not used because of their:
low strength characteristics. high alloy content. tendency toward embrittlement when subjected to vibration.
After installation of a rebuilt hydraulic hand pump, it is found that the handle cannot be moved in the pumping direction (pressure stroke). The most likely cause is an incorrectly installed:
hand pump inport check valve. inport/outport orifice check valve. hand pump outport check valve.
When repairing a small hole on a metal stressed skin, the major consideration in the design of the patch should be:
the shear strength of the riveted joint. to use rivet spacing similar to a seam in the skin. that the bond between the patch and the skin is sufficient to prevent dissimilar metal corrosion.
Fuel-boost pumps are operated:
to provide a positive flow of fuel to the engine. primarily for fuel transfer. automatically from fuel pressure.
One method of inspecting a laminated fiberglass structure that has been subjected to damage is to:
strip the damaged area of all paint and shine a strong light through the structure. use dye-penetrant inspection procedures, exposing the entire damaged area to the penetrant solution. use an eddy current probe on both sides of the damaged area.
What is the purpose of the free-wheeling unit in a helicopter drive system?
It disconnects the rotor whenever the engine stops or slows below the equivalent of rotor RPM. It releases the rotor brake for starting. It relieves bending stress on the rotor blades during starting.
The metering pins in oleo shock struts serve to:
lock the struts in the DOWN position. retard the flow of oil as the struts are compressed. meter the proper amount of air in the struts.
What is indicated by a black smoky residue streaming back from some of the rivets on an aircraft?
The rivets were excessively work hardened during installation. Exfoliation corrosion is occurring inside the structure. Fretting corrosion is occurring between the rivets and the skin.
An aircraft pressurization cycle is normally considered to be:
one complete series of events or operations that recur regularly. one take off and one landing. when the fuselage reaches its maximum pressure differential one time.
The preferred way to make permanent repairs on composites is by:
bonding on metal or cured composite patches. riveting on metal or cured composite patches. laminating on new repair plies.
Static dischargers help eliminate radio interference by dissipating static electricity into the atmosphere at:
low current levels. high voltage level. high current levels.
What should be checked when a shock strut bottoms during a landing?
Air pressure. Packing seals for correct installation. Fluid level.
Hole filling fasteners (for example, MS20470 rivets) should not be used in composite structures primarily because of the:
possibility of causing delamination. increased possibility of fretting corrosion in the fastener. difficulty in forming a proper shop head.
Oxygen systems in unpressurized aircraft are generally of the:
continuous-flow and pressure-demand types. pressure-demand type only. portable-bottle type only.
On some cabin pressurization systems, pressurization on the ground is restricted by the:
main landing gear operated switch. cabin pressure regulator. negative pressure-relief valve.
If an aircraft hydraulic system requires mineral base hydraulic fluid, but phosphate ester base hydraulic fluid is used, what will be the effect on the system?
No effect. System will be contaminated, fluids will not blend, and the seals will fail. System will be contaminated, fluids will not blend, but there will be no seal problem.
When must the radio station license be displayed in an aircraft equipped with a two-way radio?
When the aircraft is operated outside the U.S. When the aircraft is returned to service. When the aircraft is certified for IFR flight.
Which of these methods may be used to inspect fiberglass/honeycomb structures for entrapped water?
1. Acoustic emission monitoring.
2. X-ray.
3. Backlighting.
1 and 2. 1 and 3. 2 and 3.
A high-speed aircraft tire with a sound cord body and bead may be recapped:
a maximum of three times. only by the tire manufacturer. an indefinite number of times.
The voltage in an ac transformer secondary that contains twice as many loops as the primary will be:
greater and the amperage less than in the primary. greater and the amperage greater than in the primary. less and the amperage greater than in the primary.
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