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Sample questions from the 211-question bank, with answers and explanations.
Physics, Math and Fluid Lines
D. 3/8 inch
AN dash numbers indicate tubing outside diameter in sixteenths of an inch. A -6 fitting equals 6/16 inch, which reduces to 3/8 inch.
Physics, Math and Fluid Lines
D. 1.25 gal
The concentrate portion is 25% of the total 5 gallons: 5 × 0.25 = 1.25 gallons of concentrate, with the remaining 3.75 gallons being water.
Physics, Math and Fluid Lines
A. 22.4 gallons
Convert dimensions to feet: 2 ft × 1.5 ft × 1 ft = 3 cubic feet. Then convert to gallons: 3 ft³ × 7.48 gal/ft³ = 22.44 gallons.
Physics, Math and Fluid Lines
A. 59.6 psia
This is Gay-Lussac's Law: P1/T1 = P2/T2, using absolute temperature in Rankine (°F + 460). T1 = 520°R, T2 = 620°R. P2 = 50 × (620/520) = 59.6 psia.
Regulations, Records and Human Factors
C. Fatigue
Fatigue results from extended work hours or insufficient rest, impairing attention, memory, and judgment—directly explaining the missed torque step after repeated long shifts.
Aircraft Drawings, Weight and Balance
C. Bill of Materials
The Bill of Materials (also called a parts list) lists every part used in the drawing along with its part number, description, and quantity required. The title block instead identifies the drawing number, scale, and drafter, not quantities of individual parts.
Materials, Hardware and Processes
A. To distribute the clamping load and prevent the rotating nut from damaging the aluminum surface
A plain flat washer spreads the bearing load over a larger area and protects the softer aluminum surface from being scored or dented as the nut is torqued, but it does not provide any locking function.
Materials, Hardware and Processes
A. 0.25 inch
Standard practice calls for a minimum edge distance of two times the rivet shank diameter. For a 0.125-inch rivet: 2 × 0.125 = 0.25 inch. Less than this risks the sheet cracking or the rivet pulling through the edge.
Ground Operations and Servicing
C. The intake suction hazard zone that can pull a person into the engine
Turbine engine intakes create powerful suction (FOD/intake danger zone) that can pull loose objects, clothing, or even personnel into the engine at high power settings; ground crews must stay clear of this forward intake hazard area per the aircraft's ground safety diagram. Jet blast is a hazard behind the engine, not in front, and propeller hazards apply to piston/turboprop aircraft, not turbofan intakes.
Regulations, Records and Human Factors
C. A structural repair to the fuselage skin
Section 65.81 limits a mechanic's privileges to the ratings held. An Airframe-only mechanic may perform and approve maintenance on the airframe, such as fuselage skin repair, but may not approve powerplant-related work like engine overhauls, propeller components, or engine mounts.
Regulations, Records and Human Factors
B. Lack of Teamwork
Lack of Teamwork occurs when individuals fail to work together and coordinate responsibilities on a shared task, causing gaps like an item both assumed the other had completed.
Aircraft Drawings, Weight and Balance
C. Empennage
Aircraft zone charts divide the airframe into major numbered zones for maintenance reference; by common convention (ATA iSpec 2200 style numbering), the 300 series is assigned to the empennage (tail section), while 100/200 cover the fuselage, 400 covers powerplants, and 500/600 cover the wings.
Materials, Hardware and Processes
B. Add one or more washers under the nut to make up the difference in grip length
When an exact-grip-length bolt is unavailable, standard practice allows the use of one or more washers (typically up to three) under the nut to make up the difference, ensuring the bolt shank—not the threads—bears within the clamped material. Bolt threads should never bear within the joint's grip area.
Materials, Hardware and Processes
B. Intergranular corrosion
Intergranular corrosion progresses along the grain boundaries of a metal, often due to improper heat treatment, and is difficult to detect visually since surface pitting may be minimal even as internal strength is severely compromised.
Regulations, Records and Human Factors
B. A statement of the type of inspection, date, aircraft total time, and signature/certificate number of the approving mechanic
Under 14 CFR 43.11, a person performing a required inspection must record the type of inspection, date, aircraft total time in service, and their signature, certificate number, and kind of certificate held. A detailed component-by-component description is not required for a satisfactory finding.
Materials, Hardware and Processes
C. Cracking or fracture on the outer surface of the bend
Minimum bend radius specifications exist because bending sheet metal tighter than the material can withstand overstresses and stretches the outer fibers of the bend beyond their elastic/plastic limit, causing cracking or fracture at the bend's outer surface.
Materials, Hardware and Processes
C. NAS (National Aerospace Standard)
NAS bolts are manufactured to closer tolerances and often higher strength levels than standard AN bolts, and are used in critical structural applications where precise fit and higher load capability are required. AN hardware is general-purpose aviation hardware with standard tolerances.
Fundamentals of Electricity and Electronics
B. From the positive terminal to the negative terminal
Conventional current theory assumes current flows from the positive terminal, through the external circuit, to the negative terminal, opposite to actual electron flow. This is the convention used on most schematics and in most aviation maintenance training materials.
Regulations, Records and Human Factors
C. From the moment the aircraft leaves the surface until it touches down at the next landing
14 CFR 1.1 defines 'time in service' as the time from the moment an aircraft leaves the surface (takeoff) until it touches down at the next point of landing. This 'wheels off to wheels on' time is used to calculate inspection and component life intervals, not total engine run time.
Materials, Hardware and Processes
D. Eddy current inspection
Eddy current inspection induces alternating electrical currents into a conductive material and detects disruptions caused by surface or near-surface cracks; it works well on nonferrous conductive metals like aluminum and can often be performed through thin paint coatings.
Aircraft Drawings, Weight and Balance
A. The hole may be machined between 0.250 and 0.255 inch, but not smaller than 0.250
A unilateral tolerance of +0.005/–0.000 means the dimension can only vary in the positive direction, so the acceptable range is from the nominal 0.250 inch up to 0.255 inch, with no undersize allowed. This is common for hole sizes where undersizing could prevent fastener insertion.
Fundamentals of Electricity and Electronics
A. 24 V
Transformer secondary voltage is found using the turns ratio: Vs = Vp × (Ns/Np) = 120V × (20/100) = 24 volts.
Ground Operations and Servicing
B. Halon or CO2 extinguisher, rated for electrical (Class C) fires
Electrical fires (Class C) require a non-conductive extinguishing agent such as Halon or CO2 that will not conduct electricity back to the operator and won't damage sensitive electronics as much as water or foam. Water is conductive and dangerous on live electrical fires, and Class D powder is specifically for combustible metal fires like magnesium.
Aircraft Drawings, Weight and Balance
B. Break line
A break line (long break) is a jagged or S-shaped line used to show that a uniform middle portion of a long part has been omitted from the drawing to save space, while the true dimension is still noted for the full length.
Fundamentals of Electricity and Electronics
C. The rate of change of magnetic flux through the loop
Faraday's Law states that induced EMF is proportional to the rate of change of magnetic flux linking the circuit. Moving the loop faster through the field increases this rate of change, increasing the induced voltage.
Tap a card to flip it. 209 flashcards in the full deck.
AN fitting and tubing dash numbers represent the outside diameter of the tube in sixteenths of an inch.
To find a component's quantity in a mixture, multiply the total volume by the required percentage expressed as a decimal.
To convert a tank's cubic volume to gallons, calculate volume in cubic feet and multiply by 7.48 gallons per cubic foot.
For a fixed volume of gas, pressure is directly proportional to absolute temperature: P1/T1 = P2/T2.
Physical or mental exhaustion reducing a technician's alertness and performance, often from long hours or inadequate rest.
A table on an engineering drawing listing every part number, description, material, and quantity required for the assembly.
A plain steel or aluminum washer placed under a bolt head or nut to distribute bearing load and protect the structure surface, and sometimes used for shimming grip length.
The minimum distance from a rivet hole center to the sheet edge, typically 2 times the rivet shank diameter, to prevent edge cracking or rivet pull-through.
The area forward of a running turbine engine where suction can ingest loose objects, tools, or personnel, causing FOD or injury.
Defines that a mechanic may perform and approve for return to service only maintenance within the scope of the rating(s) held (Airframe and/or Powerplant).
A human factor describing failure to work cooperatively and coordinate tasks/responsibilities with others on a shared job.
A standardized method of dividing an aircraft into numbered zones so maintenance personnel can quickly locate structure, systems, and components referenced in manuals.
The grip length of a bolt should closely match the thickness of the material being joined so that the smooth shank—not the threads—bears within the joint; washers may be added to compensate for slight mismatches.
A form of corrosion that progresses along the grain boundaries of a metal, often caused by improper heat treatment, and is difficult to detect visually despite significant internal weakening.
14 CFR 43.11 specifies what must be recorded when a required inspection (annual, 100-hour, progressive, etc.) is performed, separate from general 43.9 maintenance entries.
The smallest radius to which a sheet metal part can be bent without cracking, determined by material thickness, alloy, and temper.
National Aerospace Standard hardware manufactured to closer tolerances and higher strength than standard AN hardware, used in critical structural applications.
A theoretical convention stating current flows from the positive terminal through the external circuit to the negative terminal, opposite to actual electron movement.
The time from the moment an aircraft leaves the surface of the earth until it touches down at the next point of landing; used to compute inspection and overhaul intervals.
A nondestructive testing method that induces alternating currents into a conductive material to detect surface and near-surface cracks, corrosion, or conductivity changes.
A tolerance that allows variation in only one direction from the basic dimension, expressed as plus or minus but not both.
A transformer changes voltage between primary and secondary windings based on the ratio of turns, following Vs/Vp = Ns/Np.
Fire extinguishers are matched to fire class: A (ordinary combustibles), B (flammable liquids), C (electrical), D (combustible metals).
A line, often drawn jagged or S-shaped, used on a drawing to indicate that a uniform middle portion of a long part has been left out to conserve space, while overall length is still dimensioned.
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