Sheet Metal and Non-Metallic Structures
Threaded rivets (Rivnuts) are commonly used to
Attach parts or components to sheet metal.
Cabin upholstery materials installed in current standard category airplanes must
Be at least flame resistant.
What is the material layer used within the vacuum bag pressure system to absorb excess resin during curing called?
Bleeder.
The markings on the head of a Dzus fastener identify the
Body diameter, type of head, and length of the fastener.
Shallow scratches in sheet metal may be repaired by
Burnishing.
How does acoustic emission testing detect defects in composite materials?
By picking up the "noise" of any deterioration that may be present.
Alloy 2117 rivets are heat treated
By the manufacture and do not require heat treatment before being driven.
Which of the following drill bit types work best when drilling an aramid fiber (Kevlar(c)) composite laminate?
Carbide W-Point.
Rivet gauge, or transverse pitch is the distance between the
Center of Adjacent rows.
Rivet pitch is the distance between the
Center of adjacent rivets in the same row.
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
Crazing.
Most rivets used in aircraft construction have
Dimples.
The classification for fiberglass reinforcement material that has high resistivity and is the most common is
E-glass.
Fiberglass laminate damage not exceeding the first layer or ply can be repaired by
Filling with a putty consisting of a compatible resin and clean, short glass fibers.
Select the alternative which best describes the function of the flute section of a twist drill.
Forms the cutting edges of the drill point.
What is indicated by a black 'smoky' residue streaming back from some of the rivets on an aircraft?
Fretting corrosion is occurring between the rivets and the skin.
The coefficient of expansion of most plastic enclosure materials is
Greater than both steel and aluminum.
Sandwich panels made of metal honeycomb construction are used on modern aircraft because this type of construction
Has a high strength to weight ratio.
One of the best ways to assure that a properly prepared batch of matrix resin has been achieved is to
Have mixed enough for a test sample.
The aluminum alloys used in aircraft construction are usually hardened by which method?
Heat treatment.
Longitudinal (fore and aft) structural members of a semi-monocoque fuselage are called
Langerons and stringers.
Under certain conditions, type A rivets are not used because of their
Low strength characteristics.
When comparing the machining techniques for stainless steel sheet material to those for aluminum alloy sheet, it is normally considered good practice to drill the stainless steel at a
Lower speed with more pressure applied to the drill.
The length of a rivet to be used to join a sheet of .032-inch and .064-inch aluminum alloy should be equal to
One and one-half times the rivet diameter plus .96 inch.
Superficial scars, scratches, surface abrasion, or rain erosion on fiberglass laminates can generally be repaired by applying
One or more coats of suitable resin (room-temperature catalyzed) to the surface.
(1) When performing a ring (coin tap) test on composite structures, a change in sound may be due to damage or to transition to a different internal structure. (2) The extent of separation damage in composite structures is most accurately measured by a ring (coin tap) test. Regarding the above statements,
Only No. 1 is true.
When an MS20470D rivet is installed, its full shear strength is obtained
Only after a period of age hardning.
Repairs or splices involving stringers on the lower surface of stressed skin metal wings are usually
Permitted, but are normally more critical in reference to strength in tension than similar repairs to the upper surface.
When riveting dissimilar metals together, what precautions must be taken to prevent an electrolytic action?
Place a protective separator between area of potential electrical difference.
Hole filling fasteners (for example, MS20470 rivets) should not be used in composite structures primarily because of the
Possibility of causing delimitation.
What precaution, if any, should be taken to prevent corrosion inside a repaired metal honeycomb structure?
Prime the repair with a corrosion inhibitor and seal from the atmosphere.
The most important factors needed to make a flat pattern layout are
Radius, thickness, and degree of the bend.
Aircraft structural units, such as spars, engine supports, etc., which have been built up from sheet metal, are normally
Repairable, using approved method.
The part of a replacement honeycomb core that must line up with the adjacent original is the
Ribbon direction.
Which of the following need not be considered when determining minimum rivet spacing?
Rivet length.
The classification for high tensile strength fiberglass used in aircraft structures is
S-glass
Parts fabricated from Alclad 2024-T3 aluminum sheet stock must have all
Scratches, kits, tools, nicks, etc., must be held to a minimum.
When inspecting a composite panel using the ring test/tapping method, a dull thud may indicate
Separation of the laminates.
Joggles in removed rivet shanks would indicate partial
Shear failure.
The Dzus turnlock fastener consists of a stud, grommet, and receptacle. The stud diameter is measured in
Sixteenth of an inch.
The monocoque fuselage relies largely on the strength of
Skin or covering.
What is the most common method of cementing transparent plastics?
Soak method.
A DD rivet is heat treated before use to
Soften to facilitate riveting.
The identifying marks on the heads of aluminum alloy rivets indicate the
Specific alloy used in the manufacture of the rivets.
Mild steel rivets are used for riveting
Steel parts.
When straightening members made of 2024-T4, you should
Straighten cold and reinforce.
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 surface.
You can distinguish between aluminum and aluminum alloy by
Testing with a 10 percent solution of caustic soda.
When balsa wood is used to replace a damaged honeycomb core, the plug should be cut so that
The grain is perpendicular to the skin.
(Refer to Figure 4.) The amount of material required to make the 90° bend is
0.3436 inch.
Which of the following are generally characteristic of aramid fiber (Kevlar) composites? 1. High tensile strength. 2. Flexibility. 3. Stiffness. 4. Corrosive effect in contact with aluminum. 5. Ability to conduct electricity.
1 and 2.
A potted compound repair on honeycomb can usually be made on damages less than
1 inch in diameter.
(Refer to Figure 2.) Select the preferred drawing for proper countersinking.
1.
The dimensions of an MS20430AD-4-8 rivet are
1/8 inch in diameter and 1/2 inch long.
The flat layout or blank length of a piece of metal from which a simple L-shaped bracket 3 inches by 1 inch is to be bent depends upon the radius of the desired bend. The bracket which will require the greatest amount of material is one which has a bend radius of
1/8 inch.
When repairing puncture-type damage of a metal faced laminated honeycomb panel, the edges of the doubler should be tapered to
100 times the thickness of the medal.
What should be the included angle of a twist drill for hard metal?
118°
A single-lap sheet splice is to be used to repair a section of damaged aluminum skin. If a double row of 1/8-inch rivets is used, the minimum allowable overlap will be
13/16 inch.
When drilling stainless steel, the drill used should have an included angle of
140° and turn a low speed.
A piece of flat stock that is to be bent to a closed angle of 15° must be bent through an angle of
165°
Which part of the 2017-T36 aluminum alloy designation indicates the primary alloying agent used in its manufacture?
2
Which of these methods may be used to inspect fiberglass/honeycomb structures for entrapped water? 1. Acoustic emission monitoring. 2. X-ray. 3. Backlighting.
2 and 3.
How many of the following are benefits of using microballoons when making repairs to laminated honeycomb panels? 1. Greater concentrations of resin in edges and corners. 2. Improved strength to weight ratio. 3. Less density 4. Lower stress concentrations
2, 3, and 4.
Which of the following are generally characteristic of carbon/graphite fiber composites? 1. Flexibility. 2. Stiffness. 3. High compressive strength. 4. Corrosive effect in contact with aluminum. 5. Ability to conduct electricity.
2, 3, and 4.
(Refer to Figure 6.) What is dimension D? Setback = .252 Bend allowance = .345
4.182
(Refer to Figure 7.) What is dimension F? Setback at D = .095 Setback at E = .068 Bend allowance at D = .150 Bend allowance at E = .112
5.936.
A sheet metal repair is to be made using two pieces of 0.0625-inch aluminum riveted together. All rivet holes are drilled for 1/8-inch rivets. The length of the rivets to be used will be
5/16 inch.
The length of rivet to be chosen when making a structural repair that involves the joining of 0.032-inch and 0.064-inch aluminum sheet, drilled with a No. 30 drill, is
5/16 inch.
Which rivet is used for riveting magnesium alloy structures?
5056 aluminum.
How many MS20470 AD-4-6 rivets will be required to attach a 10 x 5 inch plate, using a single row of rivets, minimum edge distance, and 4D spacing?
56
(Refer to Figure 5.) What is the flat layout dimension?
6.8 inches
What should be the included angle of a twist drill for soft metals?
90°
What type of bit should be used to drill holes in Plexiglas?
A specifically modified twist drill.
(Refer to Figure 6.) Determine the dimensions of A, B, and C in the flat layout. Setback = .252 Bend allowance = .345
A= .748, B= 1.496, C= 1.248
The purpose of a joggle is to
Allow clearance for a sheet or extrusion.
Clad aluminum alloys are used in aircraft because they
Are less subject to corrosion than uncoated aluminum alloys.
When a piece of aluminum alloy is to be bent using a minimum radius for the type and thickness of material,
The layout should be made so that the bend will be 90° to the grain of the sheet.
What is the minimum edge distance allowed for aluminum alloy single lap sheet splices containing a single row of rivets as compared to a joint with multiple rows, all rivets being equal in diameter?
The minimum edge for the single row is equal to that for the multiple row.
The strength and stiffness of a properly constructed composite buildup depends primarily on
The orientation of the plies to the load load direction.
One of the main advantages of Hi-Lok type fasteners over earlier generations is that
They can be installed with ordinary tools.
What is one of the determining factors which permits machine countersinking when flush riveting?
Thickness of the material is greater than the thickness of the rivet head.
What is the minimum spacing for a single row of aircraft rivets?
Three times the diameter of the rivet shank.
The general rule for finding the proper rivet diameter is
Three times the thickness of the thickest sheet.
What is the purpose of refrigerating 2017 and 2024 aluminum alloy rivets after heat treatment?
To retard age hardening.
What is the minimum edge distance for aircraft rivets?
Two times the diameter of the rivet shank.
What reference tool is used to determine how the fiber is to be oriented for a particular ply of fabric?
Warp clock (or compass).
Composite fabric material is considered to be the strongest in what direction?
Warp.
When necessary, what type of cutting fluid is usually acceptable for machining composite laminates?
Water only.
Which is an identifying characteristic of acrylic plastics?
Zinc chloride will have no effect.
MS20426AD-6-5 indicates a countersunk rivet which has
an overall length of 5/16 inch.
Fiberglass laminate damage that extends completely through one facing and into the core
requires the replacement of the damaged core and facing.
If a streamline cover plate is to be hand formed using a form block, a piece of dead soft aluminum should first be placed over the hollow portion of the mold and securely fastened in place. The bumping operation should be
started by tapping the aluminum lightly around the edges and gradually working down to the center.
On a sheet metal fitting layout with a single bend, allow for stretching by
subtracting the setback from both legs.
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.
Which is correct concerning the use of a file?
Apply pressure on the forward stroke, only, except filling very soft metals such as lead or aluminum.
The sharpest bend that can be placed in a piece of metal without critically weakening the part is called the
Minimum radius bend.
Which rivet is used for riveting nickel-steel alloys?
Monel.
When bending metal, the material on the outside of the curve stretches while the material on the inside of the curve compresses. That part of the material which is not affected by either stress is the
Neutral line.
A main difference between Lockbolt/Huckbolt tension and shear fasteners (other than their application) is in the
Number of locking collar grooves.
The shop head of a rivet should be
One and one-half times the diameter of the rivet shank.
