FAA A&P Airframes Oral and Practical Test – Flashcards
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What is the function of a vortex generator?
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It is designed to delay or prevent separation of the boundary layer.
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What are the 3 axis of an airplane?
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Longitudinal, Lateral, and Vertical.
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What are the 3 primary flight controls?
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Ailerons, elevator, and rudder
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Name several types of secondary flight controls and describe thier general purpose.
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Secondary flight controls consist of various types of trim tabs such as balance tabs, anti-servo, servo tabs, and spring tabs. Thier function is to assist the pilot in moving the controls and trimming the aircraft to fly hands off.
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Name several types of auxiliary flight controls and describe thier general purpose.
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The auxiliary flight controls consist of the various high-lift devices used during low-speed flight such as leading and trailing edge flaps, slats, slots, speed brakes, etc.
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What is a servo trim tab?
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It is an auxillary control, positioned by the movement of a control in the cockpit and designed to create aerodynamic forces to assist in moving a control surface.
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What is a spring tab?
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An auxillary control designed to aid the movement of a primary control at high speeds when control forces become too high
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What is a balance trim tab?
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An auxillary control designed to create aerodynamic forces to assist in moving a control surface. The tab is positioned by a control rod on the connected to a fixed surface on the same side as the horn of the tab.
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What are the four most common types of high lift devices?
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Leading and trailing edge flaps, slats, and slots.
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Describe some tools to used to check control surface travel.
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A universal propeller protractor or special control surface protractor.
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Name three mechancial methods by which flight control systems may be actuated.
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Cables, push-pull rods, and torque tubes.
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What is a fairlead?
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A device to prevent a cable form rubbing on the aircraft structure.
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What are the most likey places for a control cable to break?
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Where cables pass over pulleys or through fairleads.
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What infoemation is required before a cable rigging chart can be used?
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The ambient temperature and the cable size.
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What is the function of a cable tension regulator?
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It automatically adjust the cable tension to compensate for expansion and contraction in the aircraft structure.
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Describe the function of a rotorcraft collective pitch control.
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The collective control causes each rotor blade to change its pitch by the same amount, thus increase or decreasing the amount of lift produced by the rotor.
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Describe the function of a rotorcraft cyclic pitch control.
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The cyclic control tilts the main rotor disc by by changing the pitch angle of each rotor blade during its cycle of rotation, which causes the helicopter to move in the direction the rotor tilts.
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What mechanism is most commonly used to compensate for the torque produced by the main rotor of a helicopter?
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The tail (or anti-torque) rotor.
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How is the amont of thrust produced by the tail rotor controled?
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By moving the foot pedals
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Why should control surfaces be locked when an aircraft is parked?
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To prevent damage from the wind.
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What is the major damage to aluminum structures that is caused by exposure to the weather?
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Corrosion.
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Name several methods for forming sheet metal
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Bending or folding, streching, shrinking, bumping, and crimping.
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What are the demensions of a properly formed rivet head?
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The head should be 1 1/2 the diameter in width and 1/2 the shank diameter in height.
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Describe the markings found on the heads of A, B, D, AD and DD rivets.
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A: Plain B: Cross D: Raised Dot AD: Dimple DD: Double Dash
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What happens to the stem of a self plugging (friction lock) rivet when the rivet is installed?
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The stem is pulled until it snaps of and the remaining part is trimmed flush with the head.
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Name at least three types of self plugging mechanical lock rivets
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CherryMAX, CherryLOCK, OYLMPIC-LOC, and HuckLok rivets
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What is the difference between the tools required to pull a CherryLOCK rivet and a CherryMAX rivet?
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CherryLOCK rivet require a a tool for each different size and head shape, one pulling tool willset any size CherryMAX rivet.
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Which of the five stresses is the most common cause of rivet failure?
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Shear
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Ifa 2024 rivet must be replaced with a 2117 rivet, how do you determine the size to be used?
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For 5/32 or smaller diameter us the next larger size 2117 rivet, assuming that the edge distance and spacing meet the minimum requirements.
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Describe the process for determining the total length ofa solid rivet for a particular installation.
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Add the grip length plus 1 1/2 the diameter of the rivet.
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What minimum edge distance and spacing should be used for a single row of protruding head rivets?
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Not less than two rivet diameters from the edge and not less than three rivet diameters apart.
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How can a mechanic determine wether the countersink for a flush rivet should be dimpled or drilled
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By the thickness of the top sheet; thin sheets are dimpled while thick sheets may be countersunk.
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What actions is taken to prevent cracks from forming while dimpling magnesium or some hard sheet metals?
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Hot dimpling equipment is used to preheat and soften the metal before the dimple is formed.
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What type of damage can occur when using a rivet set that does not properly fit the rivet?
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If the radius of the set is too small, the rivet head may be damaged. An oversized set may cause damage to the sheet metal
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Why is it important to use the proper size and weight bucking bar when performing sheet metal rivevting?
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If a bucking bar is too large or heavy it may be difficult to control and may cause damage to the surrounding structure. If a bucking bar is too light it will not properly upset the rivet before work hardening occurs
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What proceedures should be followed to properly remove a solid shank rivet?
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1. Center punch the rivet 2. Drill to the base of the rivet head with the same size or one smaller drill 3. Use a pin punch to tip off the rivet head and drive the remaining shank out of the hole while supporting the remaining metal.
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What are two special calculations that must be made when bending sheet metal?
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Bend allowance and setback.
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What factors must be considered in order to determine setback?
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Thickness of the metal and bend radius
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What is done to a corner where two bends intersect to prevent cracking?
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Relief holes are drilled in the corner.
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What are two reasons for intalling a lightening hole in a sheet metal wing rib?
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Lightening holes reduce the weight and increase stiffness.
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Describe a joggle, and explain its function.
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A joggle is an offset formed at an intersection of two or more sheets of metal to allow the multiple sheets to be stacked flat against each other.
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When repairing an all-metal aircraft, how do you determine what metals should be used?
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Always use metals of the same type and thickness as the original structure.
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What are the three forms of wood commonly used in aircraft construction?
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Solid, laminated, and plywood.
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What type of wood should be used when splicing or reinforcing plywood webs?
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The same type of plywood as orginally used.
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Name at least four different types of defects found in wood.
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Knots, checks, splits, pitch pockets, cross grain, curly grain, decay, dry rot, ect.
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Can a section wood containing a hard knot be used?
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Yes, within specified limits.
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What type of glue may have been used in older wooden aircraft construction that requires careful inspection to detect deterioration?
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Casein Glue
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What are the three types of glue used in mordern aircraft repair and construction?
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Resorcinol glue, Phenol-formaldehyde glue, and epoxy resin glue.
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Is compression wood acceptable for structural repairs?
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No
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What should the various pieces of wood being joined together be kept in the same room for at least 24 hours?
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To allow the moisture content to equalize, thereby minimizing dimensional changes in the wood.
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Why is it imprtant to consider the open assembly time when gluing wooden structures?
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If the maximum open assembly time is exceeded the joint my fail since the glue may begin setting before the joint is assembled.
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Why is it important to apply the the proper clamping pressure to a glue joint?
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Clamping forces the air out of the joint, brings the wood surfaces together evenly, and is partly responsible for the strength of the glue line.
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Describe some of the methods used to apply pressure to glue joints.
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Clamps, nailing joints, power presses, brads, nails, and small screws.
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What minimum curing temperature should be observed when joining wood with various adhesives?
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70 Degrees F or as specified by the glue manufacturer.
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When inspecting wood structures why might it be important to consider stains and discolored areas?
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Stains and discoloration usually accompany decay and/or rot.
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Describe the acceptable methods used to repair elongated bolt holes found in a wooden wing spar.
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Remove the section containing the elongated bolt holes and splice in a new section, or replace the entire spar.
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What type of joint is used to splice a solid or rectangular wood spar?
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A scarf joint.
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In what areas are splices to a wood spar prohibited?
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Under an attachment fitting for the wing root, landing gear, engine mount, lift, or inter-plane strut.
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What is the maximum number of splices allowed for any single spar?
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Two.
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Describe the characteristics of a scarf joint.
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The pieces to be joined are tapered or beveled on a slope of 1:10 or 1:12
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Why must the bevel be accurate on both pieces of wood being repaired with a scarfed joint?
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The two pieces must match exactly to ensure a tight glue joint.
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What are the two primary uses for plywood in aircraft construction?
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Gusset plates and aircraft skin.
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Provide examples of at least three types of plywood skin repairs.
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1. Splayed Patches 2. Surface Patches 3. Plug Patches 4. Scarfed Patches
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What type of patch should be used to repair small holes in thin plywood skin, if the skin is less than 1/10th inch thick?
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A splayed patch may be used if the hole can be cleared out to a diameter of less than 15 thicknesses of the skin.
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What should be done to prevent a plywood patch and the pressure plate from sticking together if the glue is extruded from the joint?
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Place a piece of waxed paper or vinyl plastic between the patch and the pressure plate.
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Why are lightweight steel bushings sometimes used in wooden structure?
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Bushings prevent the wood from being crushed when bolts are tightened.
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What is the purpose of large surface area washers when used on wooden structures?
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Large washers provide additional bearing area for hardware to help perclude damage to the wood when hardware is tightened
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Name several facings and core materials used in bonded honeycomb structures intended for special applications.
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Stainless steel, magnesium, plywood, glass, nylon and cotton cloth.
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Describe the construction of a bonded honeycomb structure.
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It is a laminated structure that has a solid facing bonded to either side of a core consisting of open six-sided cells
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What must be done to the damaged area in a bonded honeycomb structure prior to begining repairs?
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The damaged area must be completely removed.
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A drill bit must have an included angle of how may degrees?
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135 Degrees
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What are the most common causes for delamination of a composite structure?
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Sonic vibration, expansion of internal moisture, liquid leakage, and a manufacturing error.
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What type of defect in, or damage to, a bonded honeycomb structure, can be repaired using the potted repair method?
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Filling a hole.
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Name some of the factors that cause crazing in transparent plastic windows and windshields.
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1. Exposure to UV light 2. Stress 3. Solvents 4. Improper handling
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How should a hole be drilled in Plexiglas to avoid damage to the hole when the drill breaks through to the underside?
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Back up the plastic with a piece of wood and feed the drill slowly.
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Name the 3 principle types of welding
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Gas Welding Electric arc welding Electric resistance welding
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What are some of the advantages of gas shielded arc welding?
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The weld is sronger, more ductile, and more corrosion resistant.
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Which method of welding is less likely to cause buckling or warping of thin metal sheets?
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Electric arc (TIG) welding.
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What is the purpose of shielding an arc weld with an inert gas?
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The gas prevents atmospheric oxygen and/or nitrogen from contaminating the weld.
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What is common method for controlling expansion when welding a joint?
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Place tack welds along the length of the joint.
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What is the effect of inadequate penatration on a weld?
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The weld will be weak.
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What is the purpose of the flux used with brazing and silver soldering?
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The flux cleans the base metal by removing any oxide film.
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What type of flame is used when torch brazing or silver soldering?
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A neutral flame.
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What must be done to a soldering iron tip to increase the amout of heat transferrred from the tip to the work?
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The tip must be free of all contaminates and properly tinned.
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What is the perferred method for welding aluminum?
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TIG Welding
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What is the perferred method for welding magnesium?
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TIG Welding
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What precautions must be observed in order to weld titanium?
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All traces of oxygen and nitrogen must kept away from the welded area.
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Describe one type of repair that could be made to a dented steel tube cluster joint.
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A formed steel plate could be welded over the damaged area.
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How can a soft flame be obtained without reducing the heat output of the torch?
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Use a larger tip and adjust the gas pressure accordingly.
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What factors determine the amount of heat delivered by a gas welding torch?
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The size of the torch tip and the gas pressure.
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When an oxyacetylene torch is extinguished which valve is turned off first?
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Turn off the acetylene gas valve first.
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When a gas welding project is completed, what safety percautions should be accomplished?
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All the valves are turned off and the gas pressures are relieved.
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What should be done to a heat treated aluminum part after welded repairs are completed?
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The part must be re-heat treated.
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Welding magnesium can createe a serious safety hazard. What is the nature of this hazard?
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Magnesium burns with a very hot flame and is very hard to extinguish.
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What technique might be used to enable a tight-fitting inner sleeve to be inserted into a tubular repair?
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The inner tube could be chilled with dry ice or in a freezer while the outer tube could be heated slightly with a torch.
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Aircraft covering fabrics are made of materials from what two sources?
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Organic materials and synthetic materials
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How would you determine the strength requirements for fabric used to re-cover an aircraft?
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The fabric must be of at least the quality and strength of the fabric used by the original manufacturer.
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What two types of organic fibers are used for covering an aircraft?
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Cotton and linen
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What is meant by warp, weft, and bias?
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Warp is the direction along the length of the fabric. Weft is the direction across the fabric at right angles to the Warp Bias isa direction at a 45 Degree angle to the warp and weft.
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What is the purpose of the selvage edge on a roll of fabric?
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It prevents the fabric from unraveling.
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What identification markingis found on the selvage edge and in which direction is the warp applied?
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The FAA-PMA stamp is found on the selvage edge and the warp is applied parrallel to the line of flight.
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How are the fabric type and strength requirements determined for fabric covered aircraft?
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The original manufacturer determines the fabric type and the strength requirements are a function of the never exceed speed and wing loading.
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What type of synthetic fibers are used for covering aircraft?
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Fiberglass and heat shrinkable polyester fibers
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Which of the several types of fabric is unaffected by moisture and mildew?
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Fiberglass
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What is the function or purpose of reinforcing tape?
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Reinforcing tape is used between the fabric and the rib stiching to prevent the lacing cord from cutting through the fabric.
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Where would you use surface tape?
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Over rib stiching and sewed seems, Over lapped edges Around corners Along leading and trailing edges
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How should the edges of drainage, inspection, and ventilation holes be reinforced?
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With plastic, aluminum, or brass grommets.
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What are the principle methods used to test the condition of fabric?
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Punch testers auch as the Maule or Seybolt tester, and labratory pull testing.
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Fabric is considered unairworthy when it has deteriorated to what percentage of its orginal strength?
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Less than 70%
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How should structure that will be covered with doped fabric be prepared following inspection and prior to covering?
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Treat it with a protective coating of paint or varnish as appropriate.
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What is a principle advantage of the envelope method for covering wings?
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Almost all the seams are machine sewed by the envelope supplier.
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What is a tie-off knot?
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A standard modified seine knot used on all stitches except the starting stitch.
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Name the three common types of machine sewed seams.
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Plain overlap, folded fell, and French fell.
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Where are anti-tear strips used?
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Under wing rib stitching when the never-exceed speed is greater than 250 mph.
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How would you determine the correct spacing for rib stiching if the orginal spacing was unknown?
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Consult the chart in the AC 43.13-1B
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Why is butyrate dope safer to use than nitrate dope?
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It is much less flammable
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What are the two types of dopes used for fabric finishes?
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Cellulose Nitrate Cellulose Acetate Butyrate
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What is the appearance of a blushing paint finish?
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Chalky or cloudy
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What finishing defect is the result of paint room temperature that is too warm?
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Pinholes or blisters
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What causes dope to blush?
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High humidity Moistutre in the spray system Application over a damp surface
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What factors cause spary paint sags and runs?
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Inadequate surface preparation Paint sprayed on too thickly
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What components or parts of the airframe must be protected form damage when using paint stripper?
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Windshields and windows, plastics, composites, synthetic rubber, and fabrics.
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What is the function of zinc chromate or wash primers
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Inhibit Corrosion Provide a good bond between the metal and the top coats
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Name serveral common types of paint used on aircraft.
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Zinc-chromate and wash primers, synthetic enamels, acrylic lacquer, and polyyurethane.
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What is the proper thinner to use with zinc chromate primer?
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Toluene
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What health and safety precautions must be observed when using the toxic solvents and thinners that are part of modern finishing systems?
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Respirators and/or masks must be worn when spraying finishes.
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If spray painting dust causes a surface to appear dry and rough, what are the most likely causes?
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Too much air pressure or the spray gun is too far from the surface being painted.
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What causes orange peel?
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Sparay pressure too high Thinner that drys too fast Cold temperatures A damp draft over the surface.
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What regulation governs the application of teh registration numbers to aircraft registered in the United States?
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FAR Part 45
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Other than appearance, what is another reason for touching up painted surfaces?
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Reduction or elimination of general corrosion problems
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What references should be used to determine if a control surface must be checked and/or rebalanced after painting?
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The manufactures service manual.
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What would be the effect if dope was used over paint or enamel?
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The dope tends to dissolve these materials.
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What are the 3 most common methods of applying paint?
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Dipping, brushing, and spraying.
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What is the effect on paint finishes if too much drier is added to the paint?
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The paint film will be brittle and tend to crack and peel.
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What paint systems mabe used with epoxy topcoats?
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Any paint system in good condition.
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What would cause an AC electric motor to run too fast?
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Excessive applied voltage or shorted field windings
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What tool is used to check a motor or a generator armature for shorts and opens under load conditions?
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A growler.
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When using a growler what indication will occur when a short exists between an armature segment?
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When a metal blade is held over the armature and a short exists in the segmant, the blade will begin to chatter.
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How is the output voltage of an alternator controlled?
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By varying the field current that excites the alternator.
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What instruments are used to monitor electrical system loads?
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Ammeters and voltmeters
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How would you identify a specific wire in a wire bundle?
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By the identification code marked on the wire.
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What tool would you use to determine the size of an unmarked wire?
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A wire gauge
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What color are the navigation lights on the wing tips?
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Left: Red Right: Green
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Name several types of electrical devices that would be considered intermittent loads on an electrical system
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Landing gear Cowl and wing flap motors Radio transmitters
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Why would it be necessary to analyze an electrical system before increasing the load on the system?
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To determine the generator capacity, wire size, and protective device capacity will not be exceeded.
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What factors should be considered when determining the wire size for a particular application?
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The system voltage Permissable voltage drop Current to be carried Wire length Continuous or intermittant load
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What is the relationship between the inside diameter od a conduit and the outside diameter of a wire bundle?
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The conduit must be 25% larger than the wire bundle
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what is the maximum number of terminal lugs that can be placed on a single terminal strip stud?
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4
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What is the proper length for a terminal jumper?
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A short as practical, but long enough to allow for free movement of the component.
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Under what conditions must a switch be derated from ir nominal rating?
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When used with inductive circuits; Circuits with high in-rush current; DC Motors
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At what point do electric motors draw the most current?
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When starting
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Circuit breakers are designed to open befre what condition occurs?
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Before the wire emits smoke
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At what point in the circuit should the protective device be located?
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As close to the power source as possible
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What type of circuit breaker may not be used in an aircraft?
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An automatic restting one.
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What part of the aircraft is identified by a white light?
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The tail
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What could cause an AC electric motor to run too slowly?
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Lack of lubrication, defective wiring, or low applied voltage.
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What should be done to make bonding or grounding connections between dissimilar metals?
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Use a suitable washer so that any corrosion will occur on the washer.
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Prior to making a continuity check, what msut be done to an electrical cicuit?
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The power must be turned off.
