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151 Cards in this Set
- Front
- Back
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What species of wood is used as a standard for strength properties of other species of wood used in aircraft structures? |
Spruce is used as the standard of which all woods are compared. |
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Is northern white pine an acceptable substitute for Spruce? |
Yes, but only if the pine is a larger size to make up for its lower strength. |
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What type of wood quality must be used in the repair of aircraft structures? |
The wood must be of aircraft quality and equivalent to its original strength or greater. |
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What is the difference between laminated wood and plywood? |
Laminated wood has the grain of all layers approximately parallel. The grain of plywood runs 90° with the adjacent ply. |
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What are two types of glue used for aircraft wood structure repair? |
They are casein and synthetic resin glue. The resin glues that are recommended for a wooden aircraft applications are the resorcinol formaldehyde type glues. |
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What method is used to prepare plywood for bending? |
The wood is soaked in hot water, and then placed in a form until completely dry. |
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What are the results of using insufficient gluing pressure when making a wood joint? |
The results will normally be thick glue lines, which indicate a weak joint. |
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What is the recommended clamping pressure for a glued joint? |
125 to 150 psi. |
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How long should a wood glue joint be kept under pressure before removing the clamps? |
The pressure time will vary depending on the temperature of the curing room. The curing temperatures are from 70°F and up. Higher temperatures will cause the glue to set faster. To be certain that the glue joint a satisfactory, it is recommended that it remain under pressure at about 85°F for a period of at least seven hours. Full joint strength will develop only after conditioning for at least two days. |
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What are some of the various methods used to apply pressure to joints in aircraft gluing operations? |
Brads, nails, screws, clamps, or hydraulic and electric power presses. |
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Why does the strength of a scarf joint depend upon the accuracy of the two beveled surfaces? |
Because an inaccurate bevel will reduce the amount of effective glue area. |
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Why is sanding unacceptable when preparing a joint for splicing? |
Because the dust created from sanding will clog the pores of the wood, preventing proper penetration of glue. |
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What type of patch is preferred for repair of stressed plywood skin and why? |
A properly prepared and inserted scarf patch is the best repair for plywood, and is preferred for most skin repairs. It differs from a splayed patch in that the edges are scarfed to a 12 to 1 slope instead of a 5 to 1 slope, and it uses reinforcements under the patch where the glue joints occur. |
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Are minerals streaks acceptable in aircraft wood? |
Yes, providing careful inspection fails to reveal any decay. |
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How do you check for decay in wood? |
By sticking the wood with a sharp pointed object and prying at the suspected decay. If the wood splinters, there is no decay. However, if the wood comes up as a chunk, then there is sufficient evidence of decay. |
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How can the moisture content of wood be determined? |
One way is to use a moisture meter. |
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What area of the wood spar may not be spliced? |
It may not be spliced under wing attachment fittings, landing gear fittings, engine mount fittings, or lift-and-interplane strut fittings. |
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What type of joint is generally used in splicing structural members in aircraft? |
A scarf joint |
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What is compression wood and why is it not acceptable for aircraft structures? |
Compression wood is wood that is characterized by high specific gravity and has the appearance of an excessive growth of Summer wood (hard, nonporous). This defect is difficult to recognize and is very detrimental to strength. Reject all material containing compression wood. |
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What are three forms of wood? |
Solid, ply, and Laminate. |
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What are two forms of wood that are acceptable for the repair of wooden aircraft skin? |
The plywood and laminated Woods are preferred for this application. |
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What would be the greatest amount of splices placed into one spar? |
Two |
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What is the largest hole diameter that can be repaired in a plywood wing spar when using a fabric patch? |
1 inch |
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What determines the required quality and strength of fabric that is to be used for covering aircraft? |
The required strength and quality of aircraft fabric is determined by the pounds per square foot of wing loading (PSF), and the never exceed airspeed of the aircraft (VNE). |
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When are anti-tear strips recommended and where are they used? |
Anti-tear strips are installed over the ribs, longerons, and stringers but are under the reinforcing tape before the fabric is installed. They are recommended for all areas in the slipstream. |
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What is the maximum permissible deterioration of aircraft fabric before it is considered un-airworthy? |
Fabric covering is considered un-airworthy when it deteriorates more than 30% from its original required tensile strength. |
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What should be the strength of the fabric used for re-covering an aircraft? |
All fabric, surface tape, reinforcing tape, thread and lacing cord used to re-cover or repair an aircraft covering should be of high-grade aircraft textile material. |
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What is the purpose and location of drain grommets in aircraft fabric? |
They allow the condensed moisture to leave the aircraft as well as furnish ventilation. Drain grommets are located on the underside of airfoils at the trailing edge as close to the rib as practical, and at the lowest point along the center of the underside of each fuselage bay. |
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How are drain grommets installed in aircraft fabric? |
Brass grommets should be mounted on fabric patches and then doped to the covering. Plastic grommets are doped directly to the covering. Both types are installed with a second coat of dope, and the drain holes are open by cutting out the fabric in the center of the grommet. |
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Name the methods of applying fabric to an aircraft wing. |
Blanket and envelope method |
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What is the purpose of reinforcing tape? |
Reinforcing tape is used over all stitching and prevents the stitching cord from tearing through the fabric. |
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What type of fabric is not affected by moisture or mildew? |
Fiberglass fabric is not affected by moisture, mildew, chemicals, and most acids. |
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What methods are used to check the strength of doped fabric. |
A fabric punch test(Maul Test), if found marginal, A lab test should be performed. |
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What type of machine-sewed seems are used in aircraft covering? |
Plain overlap seams, folded-fell seams, and French-fell seams. |
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What should be done with structure that will come in contact with doped fabric? |
Treat all parts of the structure that will come in contact with dope fabric with a protective coating such as aluminum foil, dope proof paint, or cellulose tape. |
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If the original rib stitch spacing cannot be determined when re-covering an aircraft, where can you find the rib stitch spacing that should be used? |
Use the rib stitch spacing chart in the AC 43.13–1B. |
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What is the standard tie-off knot used during rib stitching? |
A modified seine knot is used to tie off all stages except the starting stitch |
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What do you call the edge of cloth, tape, or webbing that has been woven to prevent raveling? |
Selvage edge. |
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The type of fabric used for covering aircraft are organic and synthetic. Name two organic and two synthetic types. |
The organic fibers are cotton and linen. The synthetic fibers include fiberglass and heat shrinkable synthetic fiber such as nylon and Dacron. |
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When covering aircraft, where is surface tape used? |
Sewed seams, lapped edges, and all stitching is covered with surface tape. |
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Name the advantages of using the envelope method to cover fabric aircraft. |
It saves labor because practically all sewing is done by machine. |
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How are wrinkles removed from cotton fabric? |
By wetting the wrinkles and allowing it to dry. |
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When is finishing tape applied? |
After the second coat of dope is dry, and the nap has been sanded away. |
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How wide should surface tape be when used to cover the trailing edge of an aircraft wing? |
3 inches. |
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What is the recommended type of repair for an L-shaped tear when the legs are more than 14 inches long? |
A doped on patch, as long as the never-exceed velocity is less than 150 mph. |
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Name the safety and health precautions to be observed in operating a dope room, including storage of material. |
The Dope room should be well lit and ventilated using spark proof motors, lights, and switches. All flammable material should be stored in fire proof containers in protected areas. Dope and paint rooms that are not located in a separate building should be isolated from the rest of the building by metal partitions and fireproof doors. |
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What primer is used when maximum protection of the metal is desired? |
Epoxy |
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What type of test can be performed to identify existing paint finishes? |
Apply a coat of engine oil to a small area. Nitrocellulose will soften in a few minutes, but acrylic and epoxy will show No effects. If not identified, next wipe down a small area with MEK. MEK will pick up pigment from an acrylic finish, but will not affect an epoxy coating. |
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What causes blushing when applying dope or lacquer, and how can it be prevented? |
Humid conditions. The condition may be eliminated by heating the room to decrease humidity or by using a blush-retarding thinner to increase the drying time. |
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What is the purpose of using fungicidal dope when finishing aircraft fabric? |
To prevent micro-biological deterioration(rotting) of fabric. |
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What are the identification marking requirements for United States registered fixed wing aircraft? |
The Roman capital letter (N) followed by the registration number must be displayed on both sides of the fuselage, or on both sides of the vertical tale surfaces. |
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What should the color of registration markings be? |
The color of markings should contrast their background. |
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What are two types of dope used in aircraft finishes? |
They are nitrate and butyrate. |
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What is the advantage of butyrate over nitrate? |
Less flammable. |
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What would happen if dope was ever used over paint or enamel? |
It would have the tendency to lift and remove such materials. |
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What is applied to metallic surfaces as a common resistant covering before the application of enamel or lacquer? |
Zinc chromate primer is normally used for this purpose. |
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What can be done to the surface of components to prevent filiform corrosion? |
Ensure that the primer is completely cured. |
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What are the most common methods of applying aircraft finishes? |
They are dipping, brushing, or spraying. |
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What type of paint maybe used over any paint system that is in good condition? |
Epoxy topcoats will adhere to all paint systems that are in good condition and may be used as a general touch up, including touch up of defects in baked enamel coatings. |
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What is normally the cause of runs and sags in a spray application of paint finish? |
Holding the gun too long in one place or holding the gun too close can cause too much paint to be applied in one area. |
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What causes an “orange peel” or “pebble” finish? |
Incorrect spray gun setting, incorrect air pressure, incorrect paint viscosity, and holding the gun too far from the work. |
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What causes fisheyes in paint? |
Surface contamination. |
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What is used to thin chromate primer? |
Toluene |
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Which federal regulation prescribes the size and location requirements for aircraft identification numbers? |
FAR part 45. |
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What type of materials should be thoroughly protected when using paint remover? |
Synthetic rubber surfaces, aircraft tires, fabric, and acrylics must be protected against possible contact with paint remover. |
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What instructions should be followed when covering an aircraft with material specified in an STC? |
The instructions that are included in the STC. |
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What is the grip length of a rivet? |
The grip length Is the combined thickness of the materials to be joined by the rivet. |
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Where are special rivets, such as Huck or Cherry locked rivets used? |
They are used in places where access to both sides of the riveted structure is impossible, or where limited space will not permit the use of a bucking bar. |
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What is bonded honeycomb (sandwich) construction? |
It is laminar construction consisting of a combination of alternating disimilar materials |
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What type of materials are used in honeycomb construction? |
Honeycomb construction may employ stainless steel, titanium, magnesium, plywood, resin impregnated paper, E glass, nylon, or cotton cloth in various combinations. |
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Where are sandwich construction assemblies used? |
They are used for such areas as bulk heads, control surfaces, fuselage panels, wing panels, radomes, empennage skins, or shear webs. |
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What procedures should be used to prevent damage to the hole when drilling through plexiglass? |
The plexiglass should be backed with wood and the feed slowed as the drill point Breaks through the underside of the sheet. |
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What calculations must be made when bending sheet metal? |
Bend allowance and set back must be determined. Set back depends on two factors: (1) radius, (2) thickness.Bend allowance depends on four factors: 1) the degree of bend, 2) the radius of the bend 3) the thickness of the metal, and 4) the type of metal used. |
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What factors are used to determine set back? |
The radius of the bend and the thickness of the material. Setback = radius + fitness |
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When bending sheet metal, how should the grain be in relation to the bend? |
The grain should be perpendicular to the bend. |
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What is a bend tangent line? |
The line at which the metal starts to bend. |
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What is a joggle? |
A joggle is an offset near the edge of a piece of sheet metal to allow clearence for a sheet or extrusion. |
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What are several methods used in forming sheet metal? |
Folding, bumping, cramping, shrinking, and stretching. |
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What kind of metal forming is done by bumping? |
Compound curves |
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What is crazing and how does it occur? |
Crazing is hairline cracking in the surface of plastic. It is caused by uneven heating or subjecting plastic to large stresses and exposure to harmful solvents. |
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Briefly describe the anodizing process and what purpose it serves. |
Aluminum alloys are placed in an electrolytic bath which causes a thin film of hydroxide to form on the surface of the aluminum. This anodized coating not only provides excellent resistance to corrosion, but it is also an excellent bond for paint. |
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What are the proper dimensions for the shop head of a rivet? |
1 and 1/2 times the diameter in width and 1/2 times the diameter in height after bucking. |
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When inspecting plexiglass, what should you look for? |
Crazing and discoloration. |
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What causes honeycomb structure to delaminate? |
Moisture |
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What are the acceptable repair methods for bonded honeycomb structure that has been damaged? |
One is the potted repair method the other is the laminated glass fabric cloth overlay which is applied to honeycomb damage which exceeds the repair limitations of the potted compound method. |
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What size drill should be used for the common shank rivet diameters of 3/32 inch, 4/32inch, and 5/32 inch? |
For a 3/32 rivet , a number 40. For a 4/32 rivet, a number 30. For a 5/32 rivet, a number 21. |
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What is used for hole filling in a bonded honeycomb repair? |
Potting compound. |
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What is a lightning hole? |
Lightning holes are cut into rib sections, fuselage frames, and other structural parts to decrease weight. Flanges are pressed around the holes for strength. |
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What special precautions should be observed when repairing a radome? |
The repair must retain its strength and electrical transparency. |
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What is a warp line? |
A highlighted strand in the fabric used for lay orientation. |
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What does “Pot life” mean? |
The length of time a resin will remain workable after the catalyst has been added. |
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What type of weld joint must be used to weld magnesium? |
Only butt welds are used to weld magnesium. This is to prevent the possibility of trapping contaminates . |
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Why must all flux be removed from the metal after welding magnesium? |
Any flux left on the metal will result in severe corrosion. |
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What must be done in order to successfully weld titanium? |
The weld must be shielded with inert gas such as helium or argon. |
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What is shielded arc welding? |
A gas is used as a covering shield around the arc to prevent the atmosphere from contaminating the weld. |
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What are the advantages of gas shielded arc welding? |
It results in a stronger, more ductile, and more corrosion resistant weld |
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What shielding gases are used for gas tungsten arc (TIG) welding? |
Helium and argon |
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What is an advantage of electric arc welding over gas welding? |
It causes less buckling and warping of the welded material. |
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What determines the amount of heat that will be applied to the work when welding by the Oxy- acetylene method? |
The torch tips orifice size or diameter |
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What is meant by a soft flame? |
A soft flame is when the torch adjusted so the flame makes no noise, and doesn’t push the weld puddle. |
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When gas welding, what should be turned off first? |
Acetylene. |
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What will be the result of using a torch tip that is too large or too small? |
If the torch tip is too large, the heat will be too great and holes may be burned in the metal. If the torch tip is too small, the heat provided may be insufficient to produce penetration to the proper depth causing a low strength weld |
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How do you determine the correct size filler rod to be used in welding? |
The diameter of the rod to be used is governed by the thickness of the metals being joined. |
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What is the function of flux when used in soldering? |
Flux erodes corrosion from the surface of the metal when it is heated so the solder can form a strong bond. |
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Why must acid core solder never be used on electrical wire? |
Any acid flux there is leftover will cause severe corrosion to the wire. |
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What is brazing? |
Brazing is a metal joining process in which the bonding material is a nonferrous metal with a melting point lower than that of the metals being used. It includes silver soldering, copper brazing, and aluminum brazing. It can be used to join metals that are damaged by high heat. |
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What is one method of controlling expansion when welding a joint? |
By tach welding at intervals along the joint. |
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Why is it especially desirable to use a soft flame when welding aluminum? |
To avoid blowing holes in the metal when the puddle is formed. |
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What fuel is used for gas welding aluminum? |
Oxygen and hydrogen |
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What is the purpose of using flux when welding aluminum? |
Aluminum welding flux is designed to remove the aluminum oxide by chemically combining with it. |
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What is the maximum safe pressure for Acetylene gas when welding? |
When acetylene gas is compressed in a container to pressure greater than 15 psi, it becomes dangerously unstable. At 29.4 psi, acetylene is Self explosive and only a slight shock can cause it to ignite. |
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How can dents at a steel tube cluster joint be repaired? |
Weld the specially formed steel patch over they dented area and surrounding tubes. |
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What type of flame should be used when silver soldering? |
The flame should be neutral. |
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What are the procedures for preparing a metal fuel tank for welding? |
The interior of the tank should be washed with hot water and detergent, and then steamed for minimum of 30 minutes. This procedure will vaporize and remove any residual fuel in the tank. Then fill the tank with CO2 gas from a fire extinguisher and seal the tank except for a small vent hole. |
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When splicing tubing by the inner sleeve method, what method can be used to insert a tight fitting inner sleeve into the replacement tube? |
The inner sleeve can be chilled with dry ice or in Coldwater, and the outer sleeve can be heated. This will allow for a tighter fit Repair. |
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Why is flux used on silver Solder? |
It cleans the base metal of oxide to ensure a good bond. |
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What are three types of commonly used flight control systems? |
They are the cable, the push pull tubes, and the torque tube systems. |
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What is used in large metal aircraft to keep control cable tension within acceptable limits? |
Because there is a considerable difference in temperature expansion between the aluminum aircraft structure and the steel control cables, some large aircraft incorporate cable tension regulators in the control cable systems. |
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What is a fairlead? |
It is a cable guide used to guide the cables in a straight line through or between structural members of the aircraft. |
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How much cable deflection is acceptable due to a fairlead? |
3° |
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Where does failure of control cables occur most frequently? |
Breakage of wire strands occur most frequently where cables pass over pulleys and through fairleads. |
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Which flight control surfaces are considered the primary group? |
The elevators, the ailerons, and the rudder . |
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Which flight controls are considered the secondary group? |
The trim tabs, Spring tabs, wing flaps, servo tabs, and the anti servo tabs. |
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Which flight controls are in the auxiliary group? |
This group consist of the flaps, speedbrakes, spoilers, slats, leading edge flaps, and slots. |
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How do wingflaps affect landing speed and approach angle of an aircraft? |
The use of flaps increase the camber of a wing and there for the lift of the wing, making it possible for the speed of the aircraft to be decreased without decreasing the lift produced by the wing. this permits a steeper glide angle and lower speed to be obtained for the landing approach. |
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What is a balance tab? |
It is an auxiliary control with fixed linkage that is designed in such a way that when the primary control surface is moved the tab moves in the opposite direction. Arrow dynamic forces acting on the tab assist the pilot in moving the control service. |
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What is a trim tab? |
It is an auxiliary control attached to the trailing edge of the primary control surface that is positioned by the movement of the cockpit control to reduce the workload on the pilot in maintaining a desired flight attitude. |
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What is the purpose of the collective pitch control in a helicopter? |
It is used to change the pitch of the main rotor blades therefore increasing or decreasing lift. |
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Why is it important for the blades of a helicopter rotor system to be tracked? |
To reduce vertical vibrations. |
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What is the most efficient way to check a helicopter rotor for dynamic balance? |
Use of a balance/analyzer computer |
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What unit on a helicopter is used to compensate for torque created by the main rotor? |
The tail rotor |
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What control operates the helicopter tail rotor? |
The anti-torque pedals |
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What are the three axis of an aircraft, and which control surfaces cause the aircraft to move about each axis? |
They are the longitudinal, the lateral and the vertical. The longitudinal axis extends from nose to tail and uses ailerons for roll. The lateral axis extends from wingtip to wingtip using the elevators for pitch. The vertical axis passes through the center of the airframe from top to bottom and use the rudder for yaw. |
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When installing an aircraft bolt, what precaution would you take regarding the position of the bolt? |
Where possible, the bolt head should be positioned on top when a bolt is installed vertically, and the bolt head should be forward when it is installed horizontally. |
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How is the propeller torque corrected for during assembly and rigging in some single engine aircraft? |
Some aircraft have the leading edge of the vertical stabilizer offset to the longitudinal centerline to counteract engine torque. |
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What reference publication should be used to rig aircraft, including the control system? |
You should refer to the aircraft specifications or type certificate data sheets issued by the FAA, and also to the maintenance manuals issued by the manufacturer. |
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What are vortex generators? |
Small, lower aspect ratio air force mount it on the upper surface of wings. |
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What is a servo tab? |
A cockpit controlled adjustable tab attached to the trailing edge of a primary control surface. |
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What factors are used to determine the proper cable tension? |
The size of cable and outside temperature. |
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Where can you find instructions for jacking one wheel of an aircraft to change a tire? |
The aircraft maintenance manual |
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Why are control surfaces statically balanced? |
Because an out of balance control surface can cause severe flutter. |
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What needs to be done to prepare an aircraft for an annual or 100 hour inspection? |
Remove or open all necessary inspection plates, access doors, fairings and cowlings. Then thoroughly clean the aircraft and engine. |
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What is the difference between an annual and 100 hour inspection? |
The time in-between inspections and the person who can sign it off. |
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Who has the authority to sign off and return to service a 100 hour Inspection? |
An appropriately rated mechanic |
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What are the operating conditions which make the 100 hour inspection mandatory? |
The 100 hour inspection is required for aircraft that carry persons for hire or is used to give flight instruction for hire. |
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Where can you find a checklist for the 100 hour inspection? |
FAR part 43, appendix D |
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Where would you find the recommended statement for recording the approval or disapproval for return to service of an aircraft after a 100 hour inspection? |
In FAR Part 43.11 |
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Who can approve an aircraft returned or service after an annual inspection? |
In A&P mechanic who holds an inspection authorization certificate. |
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Who can approve an aircraft for return to service after a progressive inspection has been performed? |
A certified mechanic holding an inspection authorization, the aircraft manufacturer, or a certified repaired station |
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Does an aircraft being operated under a Progressive inspection program require a 100 hours inspection if it is used to give flight instruction for hire? |
No |
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What is the maximum time that a 100 hour inspection may be extended? |
Not more than 10 hours. The 10 hours may only be used to ferry the aircraft to the next inspection site. |
