Aircraft Wood, Plastic, Sealing, Coverings, and Finishes questions

Part 147 test for Airframe.

What is the most common method of cementing transparent plastics? 

Soak Method

The coefficient of expansion of most plastic enclosure materials is 

greater than both steel and aluminum. 

Select the alternative which best describes the function of the flute section of a twist drill. 

Forms the cutting edges of the drill point

When installing transparent plastic enclosures which are retained by bolts extending through the plastic material and self-locking nuts, the nuts should be

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

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

Which is an identifying characteristic of acrylic plastics?

Zinc chloride will have no effect

What type of bit should be used to drill holes in Plexiglas?

A specially modified twist drill bit

Which is considered good practice concerning the installation of acrylic plastics? 

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

A category of plastic material that is capable of softening or flowing when reheated
is described as a 

Thermoplastic

If no scratches are visible after transparent plastic enclosure materials have been cleaned, their surfaces should be 

Covered with a thin coat of wax

The strength classification of fabrics used in aircraft covering is based on

tensile strength

When and how is finishing tape applied on a fabric-covered aircraft? 

Doped on after the 1st or 2nd coat

 The determining factor(s) for the selection of the correct weight of textile fabric to be used in covering any type of aircraft is the

speed of the aircraft and the maximum wing loading. 

Finishing tape (surface tape) is used for what purpose? 

To provide additional wear resistance over the edges of fabric forming structures. 

How many fabric thicknesses will be found in a French-fell seam? 

4

Machine-sewn seams in aircraft covering fabrics may be of which of the following types?

Folded-fell, French-fell, or plain lapped. 

When testing the strength of Grade A cotton fabric covering an aircraft that requires only intermediate grade, the minimum acceptable strength the fabric must have is

70 percent of the original strength for intermediate fabric. 

When dope-proofing the parts of the aircraft structure that come in contact with doped fabric, which of the following provide an acceptable protective coating? 

Aluminum foil and cellulose tape. 

Moisture, mildew, chemicals, and acids have no effect on

Glass fabric

 For doped and overlapping span-wise seams on a wing's leading edge, overlap the fabric at least 4 inches, and

cover with finishing tape at least 4 inches wide, with the tape centered at the outside edge of the overlap seam. 

The best method of repair for a fabric-covered surface which has an L-shaped tear, each leg of which is approximately 14 inches long, is to 

sew with a baseball stitch from the center of the tear out toward the extremity of each leg and then dope on a patch.

Fungicide and mildewicide additives are important for fabric covered aircraft, such as 

cotton and linen

Which type of coating typically includes phosphoric acid as one of its components at the time of application? 

wash primer

A correct use for acetone is

remove grease from fabric. 

If masking tape is applied to an aircraft, such as for trim spraying, and is left on for several days and/or exposed to heat, it is likely that the tape will

cure to the finish and be very difficult to remove. 

When humidity is low, what is likely to occur if hydrated wash primer is applied to unpainted aluminum and then, 30 to 40 minutes later, a finish top coat is applied? 

A glossy, blush-free finish. 

Which properly applied finish topcoat is the most durable and chemical resistant? 

Polyurethane

Aluminum pigment in dope is used primarily to

provide a silver color

Which statement is true regarding paint system compatibility? 

Old wash primer coats may be overcoated directly with epoxy finishes. 

Which of the following is a hazard associated with sanding on fabric covered surfaces during the finishing process? 

Static electricity buildup

Which defect in aircraft finishes may be caused by adverse humidity, drafts, or sudden changes in temperature? 

Blushing

When humidity is low, what is likely to occur if unhydrated wash primer is applied to unpainted aluminum and then, about 30 to 40 minutes later, a finish topcoat is applied? 

Corrosion. 

Fungicidal dopes are used in aircraft finishing as the

first coat to prevent fabric rotting and are applied thin enough to saturate the fabric. 

What is the usual cause of runs and sags in aircraft finishes? 

Too much material applied in one coat. 

Before applying a protective coating to any unpainted clean aluminum, you should

avoid touching surface with bare hands

What is used to slow the drying time of some finishes and to prevent blush? 

Retarder

If registration numbers are to be applied to an aircraft with a letter height of 12 inches, what is the minimum space required for the registration mark N1683C?
Note:
2/3 x height = character width.
1/6 x height = width for 1.
1/4 x 2/3 height = spacing.
1/6 x height = stroke or line width. 

52”

Laminated wood spars may be substituted for solid rectangular wood spars

if the same quality wood is used in both. 

The strength of a well-designed and properly prepared wood splice joint is provided by the 

glue

Where is information found concerning acceptable species substitutions for wood materials used in aircraft repair? 

AC 43.13-1B

In cases of elongated bolt holes in a wood spar or cracks in the vicinity of bolt holes, 

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

A faint line running across the grain of a wood spar generally indicates 

compression failure

Any wooden member that has been overstressed is subject to which type of failure? 

compression

Which statement about wood decay is correct?

Decay is not acceptable in any form or amount. 

Which statement concerning wood decay is correct? 

Any form or amount of decay is not permitted.

Which of the following conditions will determine acceptance of wood with mineral streaks? 

Careful inspection fails to reveal any decay. 

The I-beam wooden spar is routed to

reduce weight. 

Pin knot clusters are permitted in wood aircraft structure provided 

they produce a small effect on grain direction. 

The cantilever wing uses

no external bracing

Laminated wood is sometimes used in the construction of highly stressed aircraft components. This wood can be identified by its 

parallel grain construction

When patching a plywood skin, abrupt changes in cross-sectional areas which will develop dangerous stress concentration should be avoided by using 

circular or elliptical patches

Glue deterioration in wood aircraft structure is indicated 

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

 Compression failures in wood aircraft structures are characterized by buckling of the fibers that appear as streaks on the surface 

at right angles to the grain.

Corrosion occurs when any two ________ metals are placed together in an environment that may be exposed to moisture, gasses, salts, oils, or solid or liquid chemicals.

dissimilar

It is the natural tendency of all metals to

Return to their natural state

True or False: Sealants are used in many areas of the airplane to prevent movement of liquid, gas, or other fluids between areas in the airplane.

True

Why is the main cabin sealed?

To maintain comfortable atmospheric pressure in the cabin

How does sealing the joints and fasteners on a wing aid in fuel retention?

Prevents fuel leaks

How does sealing the joints and fasteners on the outer skin of the airplane aid in aerodynamics?

Allows the air to flow over the flush and smooth surfaces

Anywhere two surfaces come together, such as in a butt joint, lap, or fay surface, there is potential for

air or fuel leakage.

Sealing between the pressurized cabin and non-pressurized areas of the airplane maintains comfortable atmospheric pressure

in the pressurized areas

Because so many different materials are used in the construction of an airplane, there is very _____ potential that corrosion will occur.

big

Which of the following is not a function of sealants?

Lubricate the connection between two surfaces

Metals will corrode when exposed to gaseous materials like acid vapors, formaldehyde gas, ammonia gas, and _____

sulfur-containing gases.

___ is a chemical reaction of a metal with another metal in the presence of an electrically conductive fluid, causing one to erode.

Electrolysis