Metallic Structures practice questions

Answer: D) To prevent cracks and buckling where the bends meet

• AIncorrect. Rivet locations are laid out separately.
• BIncorrect. Weight savings are small; the purpose is to prevent cracks.
• CIncorrect. Drainage is not the reason for bend relief holes.
• DCorrect. Relief holes give the metal room to move at intersecting bends.

Answer: C) Number 30

• AIncorrect. That hole would be far too large.
• BIncorrect. A #40 drill is for 3/32-inch rivets.
• CCorrect. A #30 drill gives the slight clearance a 1/8-inch rivet needs.
• DIncorrect. That hole is too small.

Answer: A) The rivet is near a sheet edge where the jaws reach both ends and uniform shop heads are wanted

Rivet squeezers form uniform shop heads quickly with one operator, but only where the jaws can reach both ends of the rivet, typically near edges. Elsewhere a rivet gun and bucking bar or blind fasteners are used.

• ACorrect. A squeezer needs both sides of the work within reach of its yoke, which usually means near an edge. Under those conditions it forms uniform, repeatable shop heads with one operator.
• BIncorrect. The squeezer's reach is limited by the depth of its yoke. Rivets far from an edge are normally driven with a rivet gun and bucking bar.
• CIncorrect. A squeezer must contact both the manufactured head and the shank. One-side access calls for blind fasteners.
• DIncorrect. Limited, deep access like this is handled with a rivet gun and a suitably shaped bucking bar, not a squeezer with a fixed yoke.

Answer: C) 100 degrees

• AIncorrect. This is not the standard.
• BIncorrect. 82° is common for hardware-store screws.
• CCorrect. Standard aircraft countersunk rivets (MS20426) have a 100° head.
• DIncorrect. This is not the standard.

Answer: A) Cornice brake

A cornice brake makes straight-line bends across a sheet. Slip rolls, English wheels and shrinker/stretchers form curved shapes.

• ACorrect. A cornice (leaf) brake clamps the sheet and folds it along a straight line across its full width, so it can make long straight bends to a set angle.
• BIncorrect. A slip roll former runs sheet through three rollers to make cylinders and gentle curves, not sharp straight-line bends.
• CIncorrect. An English wheel rolls the sheet between an upper wheel and a lower anvil to stretch it into compound curves, such as fairings and cowl panels.
• DIncorrect. A shrinker/stretcher compresses or stretches an existing flange to curve it. It does not make the original straight bend.

Answer: B) From approved data such as AC 43.13-1B tables listing rivets per inch of width for the sheet and rivet size

Without manufacturer data, the number of rivets in a splice comes from approved data such as AC 43.13-1B Table 4-10. The table gives rivets per inch of width for the sheet alloy, thickness and rivet diameter, so the repair restores the original strength.

• AIncorrect. The number of fasteners removed has no direct relation to the load the splice must carry. The count must come from strength data for the material and rivet size.
• BCorrect. AC 43.13-1B Table 4-10 gives the number of rivets required per inch of splice width, based on sheet alloy, thickness and rivet diameter. This restores the original strength.
• CIncorrect. Extra rivets add weight and holes. Spacing them too closely can weaken the sheet and invite cracking. The count should match the strength required.
• DIncorrect. Rivet diameter is normally about three times the sheet thickness, and rivet count depends on splice width and load, not crack length.

Answer: D) A locking collar

• AIncorrect. Sealant is not the locking feature.
• BIncorrect. Friction-lock rivets differ from mechanically locked ones.
• CIncorrect. Blind rivets don't use cotter pins.
• DCorrect. The collar locks the stem into the rivet sleeve.

Answer: A) O – annealed

The O (annealed) temper is the softest and most ductile condition of aluminum alloy, so it forms most easily. Heat-treated (T3, T6) and strain-hardened (H18) tempers are harder and less formable.

• ACorrect. Annealed (O) material is in its softest, most ductile condition, so it is the easiest to form.
• BIncorrect. T6 is close to the alloy's peak strength and hardness, so it is much harder to form and more likely to crack in tight bends.
• CIncorrect. T3 material has been heat-treated and then strain hardened, so it is much stronger and less ductile than annealed stock.
• DIncorrect. H18 has been strain hardened to the full-hard condition, which gives it very little formability.

Answer: B) Extension of the two flanges' outside surfaces to where they meet

• AIncorrect. Rivet rows are laid out with pitch and edge distance, not mold lines.
• BCorrect. The mold line meets at the mold point, used to measure setback.
• CIncorrect. That is the cut or trim line.
• DIncorrect. Mold lines are geometric reference lines in layout.

Answer: B) A rivet shaver

• AIncorrect. That forms the shop head.
• BCorrect. A microshaver trims flush rivet heads smooth.
• CIncorrect. That installs temporary fasteners.
• DIncorrect. That measures distances.