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162 Cards in this Set

  • Front
  • Back

What is the recommended taper for a splayed patch in plywood aircraft skin

5 to 1

What is the recommended taper for a scarf patch in a plywood skin

12 to 1

What is the largest hole in a plywood skin that can be repaired with a fabric patch?

One inch diameter

How long should a glue joint be kept under pressure?

7 hours

Which area of a wooden aircraft wing spar must not contain a splice?

There must be no splice under wing-attach fittings, landing gear fittings, engine mount fittings, or lift and interplane strut fittings

How is compression wood identified?

It has a high specific gravity, it appears to have an excessive growth in summer wood

What is done to a splice in a wooden aircraft wing spar to strengthen the splice?

Reinforcing plates are glued to both sides of the splice

Why must abrupt changes in the cross-sectional area of a wooden structural member be avoided?

Concentrate stresses and can cause failure

What are three types of fabric that can be used to cover an aircraft?

Cotton, synthetic, and glass

What is the preferred seam used for machine-sewing pieces of aircraft fabric together?

French Fell seam

What type of material is used for inter-rib bracing in a fabric covered aircraft?

Cotton reinforcing tape

What type of knot is used for locking the stitches that are used for rib lacing on a fabric wing?

A modified seine knot

What determines the spacing of the rib lacing stitches on a fabric-covered aircraft wing?

Never-exceed speed

When is the finishing tape applied to a fabric covered wing?

After the second coat of dope and the nap of the fabric has been sanded off

What type of hand-sewing stitch is used when sewing in a panel of new fabric on an aircraft wing?

Baseball stitch, locked every eight to ten stitches

What type of rib lacing cord is recommended

Waxed linen cord

When are drainage grommets applied?

They are laid into the third coat of dope, at the same time the surface ape is applied

What can be done to remedy blushing that has formed on a doped surface that has just been sprayed?

Spray a very light mist coat of a mixture of one part retarder to two parts of thinner over the blushed area. Allow it to dry and spray on another coat. If this does not remove the blush, the blushed dope will have to be sanded off

What are three types of primer that may be used when painting an aircraft?

Zinc chromate primer, wash primer, and epoxy primer

What are two types of dope?

Nitrate dope and butyrate dope

What kind of dope is used on polyester synthetic fabric that has been heat-shrunk on an aircraft structure?

Nontautening butyrate dope

What type of thinner is used with zinc chromate primer?

Toluol or toluene

What are three requirements for a repair to a piece of sheet metal aircraft structure?

Must restore strength and rigidity, and must not change aerodynamic shape

What is the main function of a throatless shear?

Cut mild carbon steel up to 10-gage, stainless steel up to 12-gage, and cut irregular curves in metal

What is the purpose of a sight line when laying out sheet metal to be bent in a cornice brake?

The sight line allows the jaws of a cornice brake to be positioned so the bend made by the brake will start at the bend tangent line.

What kind of metal forming can be done by a slip roll former?

Simple curves with a large radius

What kind of metal forming is done by bumping?

Compound curves in sheet metal

What must be done to the flanges of an angle for it to be curved?

The flanges must be stretched for a convex curve and shrunk for a concave curve

what determines the minimum bend radius that can be used with a piece of sheet metal?

The thickness and hardness of the metal

What is meant by setback when bending a piece of sheet metal in a cornice brake?

Setback is the distance the jaws of the brake must be setback from the mold line to form the bend

What is meant by a joggle in a piece of sheet metal?

A joggle is a small offset near the edge of a piece of sheet metal that allows the sheet to overlap another piece of metal

What is the recommended transverse pitch to use when making a riveted two-row splice in a piece of sheet metal?

Three fourths the pitch of the rivets in the row

What type of metal should be hot-dimpled?

7075-T6, 2024-T81 aluminum alloys, and magnesium alloys should be hot-dimpled

What kind of repair can be made to a small damage of the core material and one face sheet of a piece of aluminum alloy honeycomb structure?

A potted compound repair

How is the point of a twist drill ground that is to be used for drilling transparent acrylic material?

The cutting edge should be dubbed to zero rake angle, and the included angle of the tip should be ground to 140 degrees

Why is TIG welding preferred over oxyacetylene welding for building and repairing welded steel tube?

The heat is concentrated in the weld and does not cause as much distortion as gas welding

What are two types of electric resistance welding?

Spot welding and seam welding

Why is it important for the pressure of the gas in an acetylene cylinder be kept low?

Acetylene becomes unstable when stored up 15 psi

Why must thick plates of metal be preheated before they are welded?

Controls expansion and contraction of the metal

Why should welding flux be removed?


What is the difference between brazing and welding?

In brazing the base is not melted, and in welding the base is melted

What is used as the electrode in TIG welding?

Small diameter tungsten wire

What is the function of the flux in brazing and soldering?

Flux covers the cleaned and heated metal to keep oxygen away from it.

What kind of solder is recommended for soldering electrical wires?

60/40 resin-core solder

What kind of flame should be used in welding aluminum?

A soft, neutral oxy-hydrogen flame is recommended

What is an acceptable acetylene line pressure to use when welding with an ocyacetylene rig?

5 psi

What kind of flame should be used when gas welding stainless steel?

A slightly carburizing flame

How much should the bead penetrate the material when welding two pieces of steel with a butt weld?

The joint should have 100% penetration

What is met by a soft flame?

Pressures low enough that the flame does not make noise or blow the puddle

What must be done to an aircraft fuel tank before it can be welded?

The gas fumes must all be purged from the tank by running live steam through it for at lease 30 minutes, by soaking it in hot water, or by filling it with nitrogen or carbon dioxide

What causes parasite drag on an airplane?

The friction of the air flowing over the surface

What causes dissymmetry of lift produced by the rotor of a helicopter?

The forward speed of the helicopter produces dissymmetry of lift. The rotor blade which is traveling forward as the helicopter is flying produces more lift than the blade that is traveling rearward

Why is it important that the leading edge of a super-sonic airplane wing be kept free from dents and damage?

A sharp leading edge allows an oblique shock wave to attach to the airfoil in supersonic flight. If the leading edge is dented or blunt, a normal shock wave will form and slow the air immediately behind it to a subsonic velocity

What is the purpose of vortex generators on the wing of a high-speed airplane?

Vortex generators pull high-energy air down to the surface of the wing and keep shock-induced separation from occurring

Why is it important that the blades of a helicopter rotor system be in track?

Vertical vibration can develop

Where can you find the recommended statement to use for recording the approval or disapproval of an aircraft for return to service after a 100-hour inspection?

14 CFR 43.11

Under what conditions can an aircraft be operated with a 100-hour inspection overdue?

It can be operated for no more than 10 hours after an inspection is overdue for the purpose of flying it to a place where the inspection can be performed.

Under what conditions can an aircraft that is due an annual inspection be operated?

It can only be flown with a special flight permit

What is the difference between an annual inspection and a 100-hour inspection?

There is no difference in the actual inspection

What certification is required for a mechanic to conduct a progressive inspection?

A&P with IA

Where can you find the requirements for inspecting the altimeter and static system of aircraft that are operated under IFR?

14 CFR Part 43, Appendix E

Where can you find the requirements for inspecting the ATC transponder that is installed in an aircraft?

14 CFR Part 43, Appendix F

What is the purpose of the debooster in a hydraulic power brake system?

The debooster decreases the pressure and increases the volume of the fluid going to the brakes

How is the correct amount of air in an oleo shock strut determined?

By the amount the strut extends out of the cylinder when the weight of the aircraft is on it

Where can you find the correct inflation pressure for the tires on an aircraft?

Aircraft service manual

What is the purpose of the compensator port in the master cylinder of aircraft brakes?

The compensator port in the master cylinder opens the brake reservoir to the wheel cylinders when the brakes are off, this will prevent the brakes from dragging

What is the purpose of the shuttle valve in the brake system?

The shuttle valve is an automatic transfer valve, it allows the brakes to be operated by hydraulic system pressure under all normal conditions, but if pressure is lost, it allows the brakes to be operated by the emergency backup system

What are the two basic types of hydraulic fluid that are used in modern aircraft?

Mineral base fluid and phosphate ester base fluid

What kind of filter is a micronic filter?

A filter with a special paper element

Does the main hydraulic pump take its fluid from the bottom of the reservoir, or from the standpipe?


Why are some hydraulic reservoirs pressurized?

Pressurization ensures that fluid will be supplied to the inlet of the pumps at high altitude where there is not enough atmospheric pressure to this

What is a double-action pump?

A pump that delivers fluid with the movement of the pump handle in both directions

What does an unloading valve do in a hydraulic system?

Controls system pressure by shifting pump outlet fluid from the pressurized system back into the reservoir when the system pressure is high enough

What is the purpose of the accumulator in an aircraft hydraulic system?

The accumulator holds pressure on the hydraulic fluid in the system

What is the purpose of an orifice check valve?

An orifice check valve allows full flow of fluid in one direction through the valve, but restricts the flow in the opposite direction

Where are line-disconnect fittings normally located in an aircraft hydraulic system?

Normally in the lines that connect the engine-driven pump to the hydraulic system

What is meant by a single-action hydraulic actuating cylinder?

Uses fluid to move the piston in only one direction, a spring is used for return

What kind of device is used to control the speed of movement of the piston in a pneumatic actuator?

A variable orifice

Why do most high-pressure pneumatic systems include a moisture separator?

When the pressure of stored air is reduced to the value needed, the temp drops enough to freeze any water that is in the air

What is used to flush a hydraulic system that uses Skydrol hydraulic fluid?


What is used to flush a hydraulic system that uses mineral base hydraulic fluid?

Naphtha, varsol, or stoddard solvent

What must be done to the lines that are disconnected when servicing an aircraft hydraulic system?

They must be capped with the correct fluid line cap or plug

What are two ways aircraft hydraulic reservoirs may be pressurized?

By an aspirator in the fluid return line or by bleed air from one of the engine compressors

Why do some hydraulic pressure gauges have a snubber installed between them and the hydraulic pump?

Keeps the gauges from fluctuating

How is cabin pressure controlled in a pressurized aircraft?

More pressure than is needed is pumped into the aircraft cabin, and the pressure controller modulates the outflow valve to maintain the correct pressure in the cabin

What is meant by the isobaric mode of cabin pressurization?

The isobaric mode of cabin pressurization is the mode that keeps the cabin altitude constant as the aircraft changes its flight altitude

What is meant by the constant differential mode of cabin pressurization?

After the pressure in the aircraft cabin reaches the maximum value that is allowed by structural considerations, the constant differential mode of operation is the mode that holds the pressure inside the cabin a constant amount above the outside air pressure

What is the function of the cabin outflow valve on a pressurized aircraft?

Maintains the correct amount of pressure inside the cabin, controlled by the pressure controller

What are two types of air conditioning systems that may be installed on an aircraft?

Air-cycle systems and vapor-cycle systems

What happens to a combustion heater if the flow of ventilating air is restricted?

Limit switch will cause the fuel to be shut off to the heater

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

What produces the cool air in a vapor-cycle cooling 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

Why 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 form of fog, this moisture is trapped in the moisture separator before the air is released into the cabin

What is used as refrigerant in a vapor-cycle cooling system?

A freon-type liquid know as Refrigerant 12 or R-134a

What are three ways oxygen can be carried in an aircraft?

high pressure gas, liquid form, or a solid chemical candle

What kind of gaseous oxygen must be used to service an aircraft oxygen system?

Only aviators breating oxygen

What is used to check an oxygen system for leaks?

A special leak detector liquid that is in the form of a non-oily soap

What is a continuous flow oxygen system?

an oxygen system that continuously flows a metered amount of oxygen into the mask

What is a pressure-demand oxygen system?

Flows oxygen to the mask only when the wearer inhales

What identification must be stamped on an oxygen bottle that is carried in an aircraft?

The identification DOT 3AA or TOT 3HT, the date of manufacture, and the date of all of the hydrostatic tests

Why are many of the the electrical instruments mounted in steel cases?

A steel case concentrates the flux produced by magnets in the instruments and keeps it from affecting other nearby intruments

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 kerosine

What is the maximum amount of deviation error that is allowed when a magnetic compass is installed?

10 degrees

What is the maximum static leakage for IFR aircraft?

100 feet per minute

What is the difference between a two-minute and four-minute turn and slip indicator?

A two-minute turn and slip indicator gives a one needle-width deflection for a standard rate turn, and a four-minute turn and slip indicator gives a one needle-width deflection for a half-standard rate of turn

What is used as the sensor in the fuel tank for an electronic-type fuel quantity indicating system?

Tubular capacitors which extend across the fuel tank from top to bottom

In what units is a tachometer on a turbine calibrated?

In percent of takeoff rpm

What kind of system is used to measure exhaust gas temperature of a turbine engine?

An averaging system of thermocouples arranged on the inside of the exhaust duct

What is used as a flowmeter for most of the small horizontally opposed fuel injected aircraft engines?

A pressure gauge that measures the pressure drop across the injector nozzles

What two sources of power are used to operate the gyro instruments?

Vacuum or pressure, or electric

Which frequency band is used for most aircraft comm

VHF band, between 30 and 300 meahertz

Which frequency band does the VOR equipment operate?

VHF band, between 108 and 117.95

What is the preferred location of ta VOR antenna on an airplane?

On top of the aircraft

Which component of the instrument landing system shares the antenna with the VOR?

The ILS localizer

In what frequency band does the DME equipment operate?

UHF band, between 962 and 1024 megahertz and between 1151 and 1213 meahertz

What is the preferred location of the DME antenna?

Along the center line of the belly of the aircraft far from the other antennas

On what frequency is the marker beacon signal transmitted?


What do the three marker beacon lights indicate to the pilot?

Blue is passage over the outer, amber is passage over the middle, and white is passage over any other location specified on approach

What precautions should be observed working around aircraft radar?

Radar should never be operated when there are people or buildings within 100 of the antenna sweep, and it must not be operated when the aircraft is being fueled or defueled

Which frequency band is used for long range comm?

High frequency (2-25 megahertz)

What two frequencies doe the ELT operate on?

121.5 and 243.0 megahertz

What three components of an Instrument Landing System are installed in an aircraft?

The receivers for the localizer, glide slope, and marker beacons

What kind of antenna is used for VHF communications?

A vertically polarized whip antenna

What kind of antenna is used for the ATC transponder?

A UHF stub antenna

What is the preferred location for the ATC transponder antenna?

On the belly away from other antennas

What kind of conductor is used to connect a VHF or UHF antenna?

Coaxial Cable

What two types of antennas are used with most ADF receivers?

A directional loop antenna and a nondirectional sense antenna.

Why are doublers installed with antennas mounted on the skin?

To prevent the skin from flexing and cracks

Where are fuel system strainers located?

Outlet of 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?

Produce fuel pressure for starting the engine, keep fuel vapor from locking at high altitude, and transfer fuel from one tank to another

What is met by a compensated engine-driven fuel pump?

The pumps pressure relief valve is acted on by the atmosphere, the pump varies its outlet fuel pressure so it will stay a constant amount higher than the pressure of the air entering the carburetor

Why must an aircraft fuel valve have a detent in its operating mechanism?

The detent gives the pilot a positive feel when the selector valve is in the on or off position

What characteristic is measured with the mass-flow fuel flowmeter that is used with turbine engine aircraft?

Density of fuel

What is used as a flowmeter for a fuel-injected, horizontally opposed aircraft engine?

A pressure gage that measures the pressure drop across the injector nozzles in the engine

How is a fuel leak indicated?

The dye in the fuel

What is the purpose of a drip gauge?

The drip gauge allows a mechanic to check the fuel level in a tank from the bottom of the tank

What markings must appear near the filler opening of the fuel tanks on reciprocating-engine-powered aircraft, and on a turbine-powered aircraft?

Recip-FUEL and minimum grade

Turbine-FUEL, permissible fuel designations, the maximum permissible fueling supply pressure, and maximum permissible defueling pressure

What two things must be taken into account when selecting aircraft wire size?

Current carrying capability and voltage drop

What kind of clamp is used to secure a wire bundle to the aircraft structure?

A cushioned clamp

What size generator must be used in an aircraft electrical system if the connected electrical load is 30 amps, and there is no way of monitoring the generator output?

The total continuously connect electrical load must be no more than 80% of the rated generator output

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

What kind of fault can be found in a generator armature with a growler?

Shorted coils

What is the main disadvantage of aluminum wire over copper wire for use in an aircraft electrical system?

Aluminum wire is more brittle than copper, more subject to breakage when nicked or is subject to vibration

What kind of rectifier is used in the small DC alternators installed in most light aircraft?

Six silicon diodes arranged in a three-phase, full-wave rectifier

What kind of instrument would you use to measure very high resistance?

A Megger

When is it important that aircraft electrical system wire bundles be enclosed in some type of conduit?

Any time a wire bundle is routed in an area where it is subject to abrasion or rough handling

What size aluminum wire would be proper to replace a piece of four-gauge copper wire?

Two gage, you use a wire that is two gage numbers larger

What is the smallest size aluminum wire that is approved for use in aircraft electrical systems?


What three things must be synchronized before an aircraft AC generator is placed on the same bus with another AC generator?

Voltage, frequency, and phase rotation

How can the direction of rotation of the armature of a DC shunt-wound electric motor be reversed?

By reversing the connections to the shunt field coil with reference to the armature

What is the annunciator panel in an aircraft?

A single location that contains all the warning and condition lights

Which device would likely cause the brakes to fail to release when a skid developed?

A malfunctioning antiskid valve

Where are the skid detectors located in an antiskid brake system?

In the center of the wheel hub

Where is the landing gear safety switch normally located?

On the landing gear shock struts

Where does the air come from to operate the pneumatic deicer boots on a reciprocating-engine powered airplane?

From the discharge side of the air pump that is used to operate the gyro instruments

What is met by a wet vacuum pump?

A wet pump uses engine oil, and a dry pump uses carbon vanes

How does a thermal anti-icing system operate?

Hot compressor bleed air

What is used to remove frost from aircraft?

A mixture of isopropyl alcohol and ethylene glycol

When should rain repellent be used on an airplane windshield?

Only when the windshield is wet

How are rubber deicer boots attached to the leading edges of aircraft wings and tail surfaces?

Machine screws with rivnuts or bonded to the surface with adhesive

What keeps an electrically heated windshield from overheating?

Heat sensors built into the windshield control the current that is used to heat the windshield