ACRM - Jeppesen Chapter 3

A faint line running across the grain of a wood spar generally indicates A compression failure. B shear failure. C decay.

A compression failure.

If no scratches are visible after transparent plastic enclosure materials have been cleaned, their surfaces should be A covered with a thin coat of wax. B buffed with a clean, soft, dry cloth. C polished with rubbing compound applied with a damp cloth.

A covered with a thin coat of wax.

(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 struc tures is most accurately measured by a ring (coin tap) test. Regarding the above statements, A only No. 1 is true. B only No. 2 is true. C both No. 1 and No. 2 are true.

A only No. 1 is true.

Composite inspections conducted by means of acoustic emission monitoring A pick up the "noise" of corrosion or other deterioration occurring. B create sonogram pictures of the areas being inspected. C analyze ultrasonic signals transmitted into the parts being inspected.

A pick up the "noise" of corrosion or other deterioration occurring.

The length of time that a catalyzed resin will remain in a workable state is called the A pot life. B service life. C shelf life.

A pot life.

The I beam wooden spar is routed to A reduce weight. B increase strength. C obtain uniform strength.

A reduce weight.

Fiberglass laminate damage that extends completely through one facing and into the core A requires the replacement of the damaged core and facing. B can be repaired by using a typical metal facing patch. C cannot be repaired.

A requires the replacement of the damaged core and facing.

When inspecting a composite panel using the ring test/tap-ping method, a dull thud may indicate A separation of the laminates. B an area of too much matrix between fiber layers. C less than full strength curing of the matrix.

A separation of the laminates.

One method of inspecting a laminated fiberglass structure that has been subjected to damage is to A strip the damaged area of all paint and shine a strong light through the structure. B use an eddy current probe on both sides of the dam-aged area. C use dye penetrant inspection procedures, exposing the entire damaged area to the penetrant solution.

A strip the damaged area of all paint and shine a strong light through the structure.

When balsa wood is used to replace a damaged honeycomb core, the plug should be cut so that A the grain is perpendicular to the skin. B the grain is parallel to the skin. C it is about 1/8-inch undersize to allow sufficient bonding material to be applied.

A the grain is perpendicular to the skin.

The strength and stiffness of a properly constructed composite buildup depends primarily on A the orientation of the plies to the load direction. B the ability of the fibers to transfer stress to the matrix. C a 60 percent matrix to 40 percent fiber ratio

A the orientation of the plies to the load direction.

When installing transparent plastic enclosures which are retained by bolts extending through the plastic material and self-locking nuts, the nuts should be A tightened to a firm fit, then backed off one full turn. B tightened to a firm fit, plus one full turn. C tightened to a firm fit

A tightened to a firm fit, then backed off one full turn.

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. A 1, 3, and 5. B 1 and 2. C 2, 3 and 4.

B 1 and 2.

A potted compound repair on honeycomb can usually be made on damages less than A 2 inches in diameter. B 1 inch in diameter. C 4 inches in diameter.

B 1 inch in diameter.

When repairing puncture type damage of a metal faced laminated honeycomb panel, the edges of the doubler should be tapered to A whatever is desired for a neat, clean appearance. B 100 times the thickness of the metal. C two times the thickness of the metal.

B 100 times the thickness of the metal.

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. A 1, 3, and 5. B 2, 3, and 4. C 1 and 3

B 2, 3, and 4.

What is the material layer used within the vacuum bag pressure system to absorb excess resin during curing called? A Release. B Bleeder. C Breather

B Bleeder

Which of the following conditions will determine acceptance of wood with mineral streaks? A Local irregularities do not exceed limitations specified for spiral and diagonal grain. B Careful inspection fails to reveal any decay. C They produce only a small effect on grain direction.

B Careful inspection fails to reveal any decay.

What is the most common method of cementing transpar-ent plastics? A Bevel method. B Soak method. C Heat method.

B Soak method.

In cases of elongated boltholes in a wood spar or cracks in the vicinity of boltholes, A it is permissible to ream the hole, plug with hard-wood, and redrill. B a new section of spar should be spliced in or the spar replaced entirely. C the spar may be reinforced by using hardwood rein-forcing plates

B a new section of spar should be spliced in or the spar replaced entirely.

Compression failures in wood aircraft structures are characterized by buckling of the fibers that appear as streaks on the surface A at right angles to the growth rings. B at right angles to the grain. C parallel to the grain.

B at right angles to the grain.

The strength of a well designed and properly prepared wood splice joint is provided by the A bearing surface of the wood fibers. B glue. C reinforcement plates.

B glue.

The coefficient of expansion of most plastic enclosure materials is A greater than steel but less than aluminum. B greater than both, steel and aluminum. C less than either steel or aluminum.

B greater than both, steel and aluminum.

Sandwich panels made of metal honeycomb construction are used on modern aircraft because this type of construction A may be repaired by gluing replacement skin to the inner core material with thermoplastic resin. B has a high strength to weight ratio. C is lighter than single sheet skin of the same strength and is more corrosion resistant.

B 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 A perform a chemical composition analysis. B have mixed enough for a test sample. C test the viscosity of the resin immediately after mix-ing.

B have mixed enough for a test sample.

Fiberglass damage that extends completely through a laminated sandwich structure A must be filled with resin to eliminate dangerous stress concentrations. B may be repaired. C may be filled with putty which is compatible with

B may be repaired.

The cantilever wing uses A the skin to carry most of the load to the wing butt. B no external bracing. C external struts or wire bracing

B no external bracing

Superficial scars, scratches, surface abrasion, or rain erosion on fiberglass laminates can generally be repaired by applying A a piece of resin impregnated glass fabric facing. B one or more coats of suitable resin (room temperature catalyzed) to the surface. C a sheet of polyethylene over the abraded surface and one or more coats of resin cured with infrared heat lamps.

B one or more coats of suitable resin (room temperature catalyzed) to the surface.

Laminated wood is sometimes used in the construction of highly stressed aircraft components. This wood can be identified by its A similarity to standard plywood construction. B parallel grain construction. C perpendicular grain construction.

B parallel grain construction.

A category of plastic material that is capable of softening or flowing "when reheated is described as a A thermoset. B thermoplastic. C thermocure

B thermoplastic.

Pin knot clusters are permitted in wood aircraft structure provided A no pitch pockets are within 12 inches. B they produce a small effect on grain direction. C they have no mineral streaks.

B they produce a small effect on grain direction.

Laminated wood spars may be substituted for solid rectangular wood spars A only in certain instances where the primary load is shared by one or more other original structural mem-ber. B only upon specific approval by the manufacturer or the FAA. C if the same quality wood is used in both.

C if the same quality wood is used in both.

The preferred way to make permanent repairs on compos-ites is by A Bonding on metal or cured composite patches. B riveting on metal or cured composite patches. C laminating on new repair plies.

C laminating on new repair plies.

The part of a replacement honeycomb core that must line up with the adjacent original is the A cell edge. B cell side. C ribbon direction.

C ribbon direction.

When holes are drilled completely through Plexiglas, a A Wood drill should be used. B standard twist drill should be used. C specially modified twist drill should be used.

C specially modified twist drill should be used.

When repairing large, flat surfaces with polyester resins, warping of the surface is likely to occur. One method of reducing the amount of warpage is to A use less catalyst than normal so the repair will be more flexible. B add an extra amount of catalyst to the resin. C use short strips of fiberglass in the bonded repair.

C use short strips of fiberglass in the bonded repair.

Which of these methods may be used to inspect fiber-glass/honeycomb structures for entrapped water? 1. A coustic emission monitoring. 2. X-ray. 3. Backlighting. A 1 and 2. B 2 and 3. C 1 and 3.

A 1 and 2.

Proper pre-preg composite lay-up curing is generally accomplished by 1. applying external heat. 2. room temperature exposure. 3. adding a catalyst or curing agent to the resin. 4. applying pressure. A 1 and 4. B 2 and 3. C 1, 3, and 4.

A 1 and 4.

Which fiber to resin (percent) ratio for advanced composite wet lay-ups is generally considered the best for strength? A 60:40. B 40:60. C 50:50.

A 60:40.

The classification for fiberglass reinforcement material that has high resistivity and is the most common is A E B G C S

A E

When making repairs to fiberglass, cleaning of the area to be repaired is essential for a good bond. The final cleaning should be made using A MEK (methyl ethyl ketone). B a thixotropic agent. C soap, water, and a scrub brush.

A MEK (methyl ethyl ketone).

What precaution, if any, should be taken to prevent corro-sion inside a repaired metal honeycomb structure? A Prime the repair with a corrosion inhibitor and seal from the atmosphere. B Paint the outside area with several coats of exterior paint. C None. Honeycomb is usually made from a man made or fibrous material which is not susceptible to corro-sion.

A Prime the repair with a corrosion inhibitor and seal from the atmosphere.

The classification for high tensile strength fiberglass used in aircraft structures is A S. B G. C E.

A S.

How many of the following are benefits of using micro balloons when making repairs to laminated honeycomb panels? 1. Greater concentrations of resin in edges and comers. 2. Improved strength to weight ratio. 3. Less density. 4. Lower stress concentrations. A Three. B Four. C Two.

A Three.

What is the purpose of a gusset or gusset plate used in the construction and repair of aircraft structures? A To join and reinforce intersecting structural members. B To provide access for inspection of structural attachments. C To hold structural members in position temporarily until the permanent attachment has been completed.

A To join and reinforce intersecting structural members.

When necessary, what type of cutting fluid is usually acceptable for machining composite laminates? A Water only. B Water displacing oil. C Water soluble oil.

A Water only.

Which is considered good practice concerning the installation of acrylic plastics? A When rivets are used, adequate spacer or other satisfactory means to prevent excessive tightening of the frame to the plastic should be provided. B When rivets or nuts and bolts are used, slotted holes are not recommended. C When nuts and bolts are used, the plastic should be installed hot and tightened to a firm fit before the plastic cools

A When rivets are used, adequate spacer or other satisfactory means to prevent excessive tightening of the frame to the plastic should be provided.

Which is an identifying characteristic of acrylic plastics? A Zinc chloride will have no effect. B Has a yellowish tint when viewed from the edge. C Acetone will soften plastic, but will not change its color.

A Zinc chloride will have no effect.

Repairing advanced composites using materials and techniques traditionally used for fiberglass repairs is likely to result in A an unairworthy repair. B improved wear resistance to the structure. C restored strength and flexibility.

A an unairworthy repair.

When patching a plywood skin, abrupt changes in cross sectional areas which will develop dangerous stress concentration should be avoided by using A circular or elliptical patches. B square patches. C doublers with any desired shaped patches

A circular or elliptical patches.

Glue deterioration in wood aircraft structure is indicated A when a joint has separated and the glue surface shows only the imprint of the wood with no wood fibers clinging to the glue. B by any joint separation. C when a joint has separated and the glue surface shows pieces of wood and/or wood fibers clinging to the glue.

A when a joint has separated and the glue surface shows only the imprint of the wood with no wood fibers clinging to the glue.

Which of the following, when added to wet resins, provide strength for the repair of damaged fastener holes in com-posite panels? 1. Microballoons. 2. Flox. 3. Chopped fibers. A 1 and 3. B 1, 2, and 3. C 2 and 3.

C 2 and 3.

Where is information found concerning acceptable species substitutions for wood materials used in aircraft repair? A Technical Standard Orders. B Aircraft Specifications or Type Certificate Data Sheets. C AC43.13-1B.

C AC43.13-1B.

Which statement about wood decay is correct? A Decay that occurs before the wood is seasoned does not affect the strength of the finished piece. B A limited amount of certain kinds of decay is accept-able in aircraft woods since decay affects the binding between the fibers and not the fibers themselves. C Decay is not acceptable in any form or amount.

C Decay is not acceptable in any form or amount.

What reference tool is used to determine how the fiber is to be oriented for a particular ply of fabric? A Fill clock (or compass). B Bias clock (or compass). C Warp clock (or compass).

C Warp clock (or compass).

Composite fabric material is considered to be the strongest in what direction? A ill. B Bias. C Warp.

C Warp.

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 A brinelling. B hazing. C crazing.

C crazing.

Fiberglass laminate damage not exceeding the first layer or ply can be repaired by A sanding the damaged area until aerodynamic smoothness is obtained. B trimming the rough edges and sealing with paint. C filling with a putty consisting of a compatible resin and clean, short glass fibers.

C filling with a putty consisting of a compatible resin and clean, short glass fibers.