22 Materials, Hardware & Drawings Practice Questions & Answers

1. 1. On an aircraft drawing, an edge that lies behind another surface and cannot be seen from the direction of view is shown by which line, and how is that line drawn?

   • A.A phantom line, drawn as one long dash alternating with two short dashes.
   • B.A center line, drawn as thin long dashes alternating with short dashes.
   • C.A hidden line, drawn as a series of short dashes of medium thickness.✓ Answer
   • D.A break line, drawn as a thin ruled line with freehand zigzags at intervals.

   Hidden lines represent edges or surfaces that the direction of view conceals, and the convention for them is a series of short, evenly spaced dashes of medium weight. The long-dash-two-short-dash pattern is the phantom line, a thin line of alternating long and short dashes is the center line, and a ruled line interrupted by freehand zigzags is a break line.

   Source: FAA-H-8083-30, Aircraft Drawings — the meaning of lines (hidden, center, phantom, break)Report a problem with this question

2. 2. A cross section of a spar cap is drawn off to one side of the main view, tied to a lettered cutting-plane line, and noted at twice the scale of the rest of the sheet. What is that view, and why may its scale differ?

   • A.A full section, cut entirely through the part and drawn at the stated scale only.
   • B.A revolved section, turned in place on the view and always at the sheet's scale.
   • C.A half section, cut to the center line to show inside and outside at one scale.
   • D.A removed section, set clear of the main view so a small detail can be enlarged.✓ Answer

   A removed (detail) section is drawn away from the view it was taken from and keyed to it by the lettered cutting plane. Because it stands on its own rather than being drawn on the view, it may be enlarged so a small feature can be read, and that different scale is noted with the section. A revolved section is drawn directly on the exterior view, a half section cuts halfway through a symmetrical part, and a full section cuts entirely through.

   Source: FAA-H-8083-30, Aircraft Drawings — sectional views (removed, revolved, half and full sections)Report a problem with this question

3. 3. The title block of a drawing states 'All tolerances ±1/32 inch unless otherwise specified.' One hole on the same drawing is dimensioned 2.000 +0.005 −0.002 inch. Which value governs that hole, and what is the tolerance on it?

   • A.The limits printed at the hole govern, and the tolerance on it is 0.007 inch.✓ Answer
   • B.The note in the title block governs, so the tolerance on the hole is 1/32 inch.
   • C.Both apply, so the tolerance is 1/32 inch added to the 0.007 inch at the hole.
   • D.The limits at the hole govern, but the tolerance is only the 0.005 plus figure.

   A blanket tolerance in the title block applies only to dimensions that do not carry limits of their own; a dimension that states its own allowances governs wherever it appears. Tolerance is the total permissible variation, that is the sum of the plus and the minus allowance, so 0.005 + 0.002 = 0.007 inch, and the part is acceptable between 1.998 and 2.005 inch.

   Source: FAA-H-8083-30, Aircraft Drawings — tolerances and title block notes (tolerance is the sum of plus and minus allowances)Report a problem with this question

4. 4. Which statement about a schematic diagram of an aircraft system is true?

   • A.It shows the components in their true size and shape and in the place each one occupies in the aircraft.
   • B.It shows simple rectangles for each unit, while the block diagram carries the coded electrical wiring.
   • C.It locates each unit in the airframe, while the installation diagram explains the principle of operation.
   • D.It shows the components with respect to each other and how the system works, not where they sit in the aircraft.✓ Answer

   A schematic is a troubleshooting and training tool: it shows each component in relation to the other components of the system and explains the principle of operation, and it deliberately ignores actual size, shape and location in the aircraft. The installation diagram is the one that shows where components are located, the block diagram simplifies relationships with rectangles, and the wiring diagram carries coded electrical circuitry.

   Source: FAA-H-8083-30, Aircraft Drawings — diagrams (installation, schematic, block and wiring)Report a problem with this question

5. 5. A 37-degree single flare has been formed on aluminum alloy tubing. Which condition shows that the flare was formed correctly?

   • A.It shows fine radial splits at the lip, which are closed and sealed as the nut is drawn up tight on the cone.
   • B.It is smooth and concentric, and its outside diameter seats on the cone without passing the sleeve edge.✓ Answer
   • C.Its outside diameter is smaller than the cone, so only the outer edge of the lip touches the fitting.
   • D.Its outside diameter reaches past the sleeve, giving the nut extra metal to squeeze against the cone.

   A correctly formed flare is smooth, concentric and of even wall thickness, and free of cracks, splits, scratches or die marks. Its outside diameter must be large enough for the flare to seat fully on the fitting cone, yet not so large that it extends past the outside diameter of the sleeve or nut seat, since the sleeve has to bear evenly on the back of the flare. Any split at the lip means the flare is cut off and remade; tightening cannot seal it.

   Source: FAA-H-8083-30, Fluid Lines and Fittings — flaring tubing; AC 43.13-1, tube flares and flared fittingsReport a problem with this question

6. 6. A flareless fitting whose sleeve was preset on the tube earlier is being reinstalled. After the nut is run up by hand until a rise in torque is felt, how much further is it turned?

   • A.About one-sixth turn further, and never more than one-third turn, then check the joint for leaks.✓ Answer
   • B.About one and one-quarter turns further, the same amount used when the sleeve was first preset.
   • C.Until the wrench will turn no further, since a sleeve already preset cannot be overtightened on the tube.
   • D.A full turn and a half further, so the sleeve cuts a new bite into the tube ahead of the cone.

   Presetting is what makes the sleeve bite the tube; reinstallation only reseats that bite. The nut is run up until a definite rise in torque shows the sleeve has contacted the fitting cone, then turned about one-sixth turn — one flat — and never beyond one-third turn. Turning further collapses the tube behind the sleeve and the joint will leak or fail, so the amount of turn, not wrench feel, is the control.

   Source: FAA-H-8083-30, Fluid Lines and Fittings — flareless tube fittings, presetting and installationReport a problem with this question

7. 7. Which statement about installing a flexible hose assembly is true?

   • A.It is fitted with 5 to 8 percent slack because it shortens under pressure, and a spiralled lay line means it is twisted.✓ Answer
   • B.It is fitted drum tight because it lengthens under pressure, and a spiralled lay line means it flexed normally in use.
   • C.It is fitted with slack because it lengthens under pressure, and the lay line marks the smallest bend radius allowed.
   • D.It is fitted with slack only to damp vibration, and the lay line shows the direction of fluid flow through the hose.

   A flexible hose contracts in length, by as much as 8 percent, when it is pressurized, so it is installed with roughly 5 to 8 percent slack; a hose pulled tight would load its end fittings and the structure when the system comes up to pressure. The lay line printed lengthwise on the hose is a straightness reference: if it spirals around the hose after installation, the hose was twisted and must be loosened and reinstalled straight.

   Source: FAA-H-8083-30, Fluid Lines and Fittings — flexible hose installation (slack and lay line); AC 43.13-1, hose installation practicesReport a problem with this question

8. 8. Electrochemical corrosion cannot take place unless four conditions exist at the same time. Which set is correct?

   • A.An anode, a cathode, a metal temperature above 70 °F, and an oxidizing atmosphere at the surface.
   • B.An anode, a cathode, an electrolyte in contact with both, and a conductive path between them.✓ Answer
   • C.Two unlike metals, an electrolyte, direct sunlight on the joint, and moisture trapped in a crevice.
   • D.An anode, an electrolyte, an organic paint film, and relative humidity higher than 78 percent.

   Electrochemical attack is a small battery on the metal: an anodic area, a cathodic area, an electrolyte wetting both, and a conductive path for electrons to travel from anode to cathode. It is the anodic material that is destroyed, because it is the member that gives up electrons, and removing any one of the four conditions — usually the electrolyte, by sealing, draining or coating — stops the cell.

   Source: FAA-H-8083-30, Cleaning and Corrosion Control — electrochemical attack (anode, cathode, electrolyte, conductive path)Report a problem with this question

9. 9. An extruded 7075-T6 spar cap has its surface lifting in leaves, with the layers of metal forced apart by a bulky white deposit between them. Which form of corrosion is this, and what lifts the layers?

   • A.Filiform corrosion, whose wormlike traces run beneath the finish and undercut the paint film into flakes.
   • B.Surface corrosion, whose general etching roughens the outer skin and loosens the top layer of the metal.
   • C.Exfoliation, an advanced intergranular attack whose swelling corrosion products push the grain layers apart.✓ Answer
   • D.Fretting corrosion, whose rubbing between tightly fitted parts wears the surface into loose thin flakes.

   Exfoliation is intergranular corrosion that has advanced far enough that its corrosion products, which take up more volume than the metal they replaced, force the elongated grains apart and lift the surface in leaves or flakes. It shows up most often in extruded sections such as spar caps, where the grain is drawn out in the direction of extrusion, and its extent is confirmed with ultrasonic or eddy current inspection.

   Source: FAA-H-8083-30, Cleaning and Corrosion Control — forms of corrosion (exfoliation of extruded high-strength alloys)Report a problem with this question

10. 10. Which statement about filiform corrosion is true?

    • A.It runs as wormlike lines under an organic finish, occurs below 70 percent relative humidity, and is prevented by storage above 78 percent.
    • B.It appears as a white powdery bloom on bare metal, occurs only in salt spray, and is prevented by a fresh water rinse.
    • C.It appears as a green film on bare copper alloy, occurs above 90 percent relative humidity, and is prevented by oiling.
    • D.It runs as wormlike lines under an organic finish, occurs at 78 to 90 percent relative humidity, and is prevented below 70 percent.✓ Answer

    Filiform is an oxygen concentration cell corrosion that grows as fine wormlike filaments beneath an organic coating, and it takes hold when relative humidity is between about 78 and 90 percent and the surface is slightly acidic. The two humidity figures are not the same: the attack occurs in that band, while prevention is storage below 70 percent relative humidity. On aluminum the traces cross one another, which deepens the damage, and left alone the attack can develop into intergranular corrosion around fasteners and seams.

    Source: FAA-H-8083-30, Cleaning and Corrosion Control — filiform corrosion (occurs at 78–90% RH; prevented by storage below 70% RH)Report a problem with this question

11. 11. A 7075-T6 forged fitting is suspected of corrosion along its grain boundaries following an improper heat treatment, and nothing can be seen at the surface. Which statement is correct?

    • A.Intergranular attack always shows as surface pitting first, so a close visual check with a magnifier will find it.
    • B.Intergranular attack can exist with no surface evidence, so eddy current or ultrasonic inspection is used to find it.✓ Answer
    • C.Intergranular attack occurs only where two dissimilar metals touch, so opening the joint and inspecting it finds it.
    • D.Intergranular attack is confined to the outermost grains, so a dye penetrant inspection will reliably reveal it.

    Intergranular corrosion attacks along the grain boundaries of an alloy whose structure is not uniform, which is why high-strength alloys such as 2014 and 7075 are susceptible when heat treatment was improper, and it can be well advanced with no visible evidence at the surface. Because the damage is below the surface it must be found by a method that reads below it — eddy current or ultrasonic; penetrant only shows discontinuities that are open to the surface.

    Source: FAA-H-8083-30, Cleaning and Corrosion Control — intergranular corrosion; AC 43.13-1, corrosion inspection and NDI methodsReport a problem with this question

12. 12. Corrosion is found under a strip of tape left on a bare aluminum panel, and along the faying edge of a joint between two pieces of the same alloy. Which form is this, and why does it occur where the metals are alike?

    • A.Concentration cell corrosion; unequal ion or oxygen levels across the wetted surface make one area anodic.✓ Answer
    • B.Galvanic corrosion; the adhesive on the tape behaves as a dissimilar metal and drives current in the joint.
    • C.Surface corrosion; direct chemical attack by the tape adhesive etches the bare metal evenly under it.
    • D.Stress corrosion cracking; the clamp-up load plus trapped moisture opens cracks along the joint edge.

    Concentration cell, or crevice, corrosion needs only one metal. Where the film of electrolyte differs from point to point in dissolved metal ions or in dissolved oxygen — under tape, dirt or debris, or in the tight crevice of a joint — the starved area becomes anodic to the rest of the surface and corrodes. That is exactly why it appears at faying edges between two pieces of identical alloy, where galvanic action between unlike metals cannot be the cause.

    Source: FAA-H-8083-30, Cleaning and Corrosion Control — concentration cell (crevice) corrosion, metal-ion and oxygen cellsReport a problem with this question

13. 13. An aluminum alloy bracket is bolted directly against a graphite/epoxy panel and the joint is wetted by condensation. Which member corrodes, and why?

    • A.The graphite, because carbon fiber is anodic to aluminum and gives up electrons to the bracket.
    • B.Neither one, because graphite is not a metal and cannot form a galvanic couple with an aluminum alloy.
    • C.The aluminum, because it is anodic to carbon fiber and gives up electrons to the more cathodic graphite.✓ Answer
    • D.Both about equally, because the two sit close together in the galvanic series of airframe materials.

    Carbon fiber conducts and sits near the noble, cathodic end of the galvanic series, far from aluminum, so in a wetted joint the aluminum is the anode: it gives up electrons and it is the member that is destroyed. The wider the separation in the series, the faster the attack, and it is worse still when the anodic aluminum area is small relative to the composite. The couple is broken by separating the two with sealant, primer, a fiberglass ply or tape.

    Source: FAA-H-8083-30, Cleaning and Corrosion Control — dissimilar metal (galvanic) corrosion and protection of dissimilar material contactsReport a problem with this question

14. 14. Light surface corrosion is to be removed from a 2024-T3 Alclad skin. Which statement is correct?

    • A.Use steel wool or a steel wire brush, which cut faster and leave the cladding brighter than aluminum does.
    • B.Sand through the cladding into the core alloy, since the core carries the load and the cladding adds none.
    • C.Use aluminum wool or a pad kept only for aluminum, and work lightly so the pure aluminum cladding stays.✓ Answer
    • D.Leave an alkaline cleaner on the skin, which lifts the corrosion without attacking the cladding under it.

    Alclad carries a layer of nearly pure aluminum about 5.5 percent of the sheet thickness on each side, and that layer protects the core alloy both as a barrier and electrolytically, so removal must be light enough to leave it intact. Steel wool and steel wire brushes are prohibited on aluminum because embedded steel particles start dissimilar metal corrosion, alkaline cleaners attack aluminum, and the reworked area is treated with a chemical conversion coating afterward.

    Source: FAA-H-8083-30, Cleaning and Corrosion Control — corrosion removal from aluminum and Alclad surfacesReport a problem with this question

15. 15. What does the designation 2024-T3 tell a mechanic about the material?

    • A.Copper is the main alloying element, and the metal was solution heat treated, cold worked, and then aged.✓ Answer
    • B.Zinc is the main alloying element, and the metal was solution heat treated and then artificially aged.
    • C.Manganese is the main alloying element, and the metal was strain hardened only, with no heat treatment.
    • D.Magnesium is the main alloying element, and the metal was annealed after forming to relieve stresses.

    In the four-digit wrought aluminum system the first digit names the principal alloying element: 1xxx is 99 percent aluminum, 2xxx copper, 3xxx manganese, 4xxx silicon, 5xxx magnesium, 6xxx magnesium and silicon, 7xxx zinc. The letter in the suffix names the basic temper — F as fabricated, O annealed, H strain hardened, T heat treated — and T3 specifically means solution heat treated, cold worked, and naturally aged to a substantially stable condition.

    Source: FAA-H-8083-30, Aircraft Materials — aluminum alloy four-digit designations and temper designationsReport a problem with this question

16. 16. Why are 2017-T and 2024-T rivets held in a refrigerator after solution heat treatment while 2117-T rivets are not?

    • A.Those two alloys age harden at room temperature, and cold storage holds them soft until they are driven.✓ Answer
    • B.2117 age hardens faster than they do, so it is driven straight from the bin before it can harden further.
    • C.Chilling anneals those two alloys, while 2117 is annealed at the mill and needs no softening in the shop.
    • D.Those two alloys take up moisture that starts corrosion, and dry cold storage keeps them free of water.

    2017-T and 2024-T begin to age harden at room temperature as soon as they are solution heat treated and quenched, and refrigeration retards that natural aging, which is why they are called icebox rivets; kept below freezing they stay driveable for about two weeks. Once taken out they must be driven quickly — 2017-T within roughly an hour and 2024-T within 10 to 20 minutes — or they must be heat treated again. 2117-T develops its properties without that, is driven as received, and is therefore the common field rivet.

    Source: FAA-H-8083-30, Aircraft Hardware — solid shank rivets, icebox rivets and 2117-T field rivetsReport a problem with this question

17. 17. A bolt carries the part number AN4-7A. What does that number tell the mechanic?

    • A.A shank 4/8 inch in diameter, a grip 7/16 inch long, and a head drilled in three places for wire.
    • B.A shank 1/4 inch in diameter, a grip 7/8 inch long, and a shank not drilled for a cotter pin.✓ Answer
    • C.A shank 4/32 inch in diameter, a grip 7/8 inch long, and a shank drilled to take a cotter pin.
    • D.A shank 1/4 inch in diameter, an overall length of 7 inches, and an aluminum alloy shear bolt.

    In the AN hex head bolt series AN3 through AN20, the number following AN gives the shank diameter in sixteenths of an inch, so AN4 is 4/16 or 1/4 inch. The dash number gives grip length in eighths of an inch, so -7 is 7/8 inch, and grip should match the thickness of the material being bolted. A letter A after the dash number means the shank is undrilled; with the A omitted the shank is drilled for a cotter pin.

    Source: FAA-H-8083-30, Aircraft Hardware — AN bolt identification and part numbering (diameter in 1/16 in., grip in 1/8 in., suffix A undrilled)Report a problem with this question

18. 18. In which installation is a fiber insert self-locking nut prohibited?

    • A.On a bolt that clamps the inner race of a control pulley bearing so that the race cannot turn on it.
    • B.On a bolt in a bracket attachment that is torqued to the value given in the current maintenance manual.
    • C.On a bolt at an accessory mount that is well away from the engine exhaust and from its radiated heat.
    • D.On a hinge bolt at a control surface, where the bolt itself turns in the fitting as the surface moves.✓ Answer

    Self-locking nuts, the fiber insert type included, must not be used at any joint that subjects the nut or the bolt to rotation, because the locking action depends on friction against the threads and rotation wears it away until the nut no longer locks. A bolt that turns in a fitting as a control surface moves is exactly that condition. They may be used at antifriction bearings and control pulleys only when the bolt and nut clamp the inner race so the race cannot turn, and the fiber type is also barred where temperatures are high.

    Source: AC 43.13-1, Aircraft Hardware — self-locking nuts, prohibited applications (joints subject to rotation)Report a problem with this question

19. 19. A nut must receive 600 inch-pounds of torque. A 5-inch drive-end extension is fitted in line between the torque wrench drive and the socket, and the wrench itself measures 10 inches from its drive to the center of the handle grip. What should the wrench read?

    • A.300 inch-pounds, because the indicated value is halved whenever an extension is used.
    • B.900 inch-pounds, because the reading is raised in proportion to the length added.
    • C.600 inch-pounds, because an extension in line with the handle changes nothing.
    • D.400 inch-pounds, because the extension lengthens the lever arm working on the nut.✓ Answer

    An extension at the drive end lengthens the lever arm between the hand and the fastener, so the fastener receives more torque than the wrench shows and the wrench must be set lower. With L the wrench length and A the extension, indicated = desired x L / (L + A) = 600 x 10 / 15 = 400 inch-pounds. An extension added at the handle end alone does not change the reading on a ratchet or rigid wrench, and none is ever used on a flexible beam wrench.

    Source: AC 43.13-1, torque wrench use with a drive-end extension (torque conversion formula)Report a problem with this question

20. 20. Which statement about published torque values and the condition of the threads is true?

    • A.They assume lightly oiled threads, and a dry fastener pulled to the same reading ends up under-tensioned.
    • B.They apply to threads in any condition, because a torque wrench reads bolt tension rather than friction.
    • C.They assume clean dry threads, and oiling the threads makes the same reading give far more bolt tension.✓ Answer
    • D.They assume dry threads, but oil lowers the tension reached, so the value read must then be increased.

    A torque wrench measures the twisting effort applied, not the tension produced in the bolt, and most of that effort is spent overcoming friction in the threads and under the bearing face. Published values therefore assume clean, dry, unlubricated threads. Oil or antiseize cuts the friction, so the same wrench reading puts far more tension into the bolt and can stretch or fail it. Lubricate only where the maintenance data specifically calls for it, or on corrosion-resistant steel parts where that is specified.

    Source: AC 43.13-1, torque values and lubrication of threaded fasteners (values apply to clean, dry threads)Report a problem with this question

21. 21. Two widely spaced bolt heads are being safetied by the double twist method. Which practice is correct?

    • A.Use new wire, route it so the pull on each bolt resists tightening, and leave a pigtail of about 2 inches.
    • B.Use new wire, route it so the pull on each bolt is toward tightening, and leave a pigtail of 1/4 to 1/2 inch.✓ Answer
    • C.Reuse sound wire, route it so the pull is toward tightening, and leave a pigtail long enough to grip.
    • D.Use new wire, take in as many as six bolts in one run, and cut the pigtail off flush with the last twist.

    Safety wire is always new wire, never reused, and it must be routed so that any tendency of a fastener to loosen puts the wire in tension in the tightening direction — wire run the other way lets the fastener back off before the wire even comes taut. The pigtail is 1/4 to 1/2 inch, three to six twists, bent back against the part so it cannot snag. For widely spaced units no more than three may be safetied in one series.

    Source: AC 43.13-1, safetying methods — safety wire, double twist method (new wire, pull toward tightening, 1/4 to 1/2 in. pigtail, maximum three widely spaced units)Report a problem with this question

22. 22. A cast aluminum alloy component is suspected of a flaw lying just below its surface. Which inspection method fits the part and the flaw, and why?

    • A.Magnetic particle, because it shows subsurface flaws in any metal once the part is magnetized two ways.
    • B.Eddy current, because it works on any metal that conducts and shows surface and subsurface flaws alike.✓ Answer
    • C.Visual with a borescope, because a flaw under the surface distorts it enough to be seen in strong light.
    • D.Dye penetrant, because the developer draws the penetrant out of subsurface flaws as well as open ones.

    Magnetic particle works only on ferromagnetic material, so an aluminum casting rules it out, and penetrant reveals only discontinuities that are open to the surface, so a flaw lying below it produces no indication. Eddy current is applicable to any electrically conductive material, needs no couplant, and detects both surface and subsurface discontinuities. Ultrasonic or radiography could also reach a subsurface flaw, but ultrasonic requires a couplant and a reference standard, and radiography does not indicate the depth of the discontinuity.

    Source: FAA-H-8083-30, Inspection Concepts and Techniques — nondestructive inspection methods (eddy current, magnetic particle, penetrant, ultrasonic, radiography)Report a problem with this question

Practice questions based on 14 CFR Parts 43 and 65 and the FAA Aviation Maintenance Technician Handbook—General (FAA-H-8083-30). This site is not affiliated with or endorsed by the Federal Aviation Administration. This bank covers the GENERAL written test only; the Airframe and Powerplant written tests and the oral and practical exams are separate. Torque values, servicing quantities, corrosion rework limits, and inspection criteria always come from the manufacturer's current maintenance data and the applicable airworthiness directives — never from a practice test. Confirm current eligibility and testing requirements with the FAA before you test. About the A&P mechanic certificate →