2026 Jeppesen Airframe Oral

What is the function of a vortex generator?

It is designed to delay or prevent separation of the boundary layer.

What are the three axes of an airplane?

Longitudinal, lateral, and vertical.

What are the three primary flight controls of an aircraft?

The ailerons, elevator, and rudder.

What are secondary flight controls?

Consists of various types to trims tabs such as balance tabs, anti-servo and servo tabs, and spring tabs. They assist the pilot in moving the controls and to trim the aircraft to fly hands-off.

What are auxiliary flight controls?

They consist of high-lift devices such as leading and trailing edge flaps, slats, slots, and speed brakes.

What is a servo trim tab?

An auxiliary control designed to create aerodynamic forces to assist in moving a control surface.

What is a spring tab?

An auxiliary control designed to aid the movement of a primary control at high speeds.

What is a balance trim tab?

An auxiliary control designed to create aerodynamic forces to assist in moving a control surface.

What are the four most common types of high lift devices?

Leading and trailing edge flaps, slats, and slots.

What tools are used to check control surface travel?

A universal propeller protractor or special control surface protractor.

What are three mechanical methods for actuating flight control systems?

Cables, push-pull rods, and torque tubes.

What is a fairlead?

A device to prevent a cable from rubbing on the aircraft structure.

Where are the most likely places for a control cable to wear or break?

Where the cables pass over pulleys or through fairleads.

What is the major type of damage to aluminum structures caused by weather?

Corrosion.

What are methods for forming sheet metal?

Bending or folding, stretching, shrinking, bumping, and crimping.

What are the dimensions of a properly formed rivet head?

The head should be 1 1/2 times the shank diameter in width and 1/2 the shank diameter in height.

What markings are found on the heads of A, B, D, AD, and DD rivets?

A rivets are plain, B rivets have a cross, D rivets have a raised dot, AD rivets have a dimple, and DD rivets have a double dash.

What happens to the stem of a self-plugging rivet when installed?

The stem is pulled until it snaps off and the remaining part is trimmed flush.

What are types of self-plugging mechanical lock rivets?

CherryMAX®, CherryLOCK®, OLYMPIC-LOK®, and Huck Lok® rivets.

What is the difference between tools for CherryLOCK and CherryMAX rivets?

CherryLOCK requires a tool for each size and shape; CherryMAX uses one tool for all sizes.

What is the most common cause of rivet failure?

Shear.

How to determine the size of a 2117 rivet replacing a 2024 rivet?

For 5/32" or smaller diameter, use the next larger size 2117 rivet.

How to determine the total length of a solid rivet for installation?

Add the grip length plus 1 1/2 times the rivet diameter.

What is the minimum edge distance for protruding head rivets?

Not less than two rivet diameters from the edge and not less than three rivet diameters apart.

How to determine if a countersink for a flush rivet should be dimpled or drilled?

By the thickness of the top sheet; thin sheets are dimpled, thick sheets may be countersunk.

What are the three forms of wood used in aircraft construction?

Solid, laminated, and plywood.

What type of wood should be used for splicing plywood webs?

The same type of plywood as originally used.

What types of defects are found in wood?

Knots, checks, splits, pitch pockets, cross grain, curly grain, decay, dry rot.

Can wood with a hard knot be used?

Yes, within specified limits.

What type of glue was used in older wooden aircraft construction?

Casein glue.

What are the three types of glues used in modern aircraft construction?

Resorcinol glue, Phenol-formaldehyde glue, and epoxy resin glue.

Is compression wood acceptable for structural repairs?

No.

Why should the various pieces of wood being joined be kept in the same room for at least 24 hours prior to joining?

To allow the moisture content to equalize, minimizing dimensional changes in the wood.

Why is it important to consider the open-assembly time when gluing wooden structures?

If the maximum open-assembly time is exceeded, the joint may fail as the glue may begin setting up before the joint is assembled.

Why is it important to apply the proper clamping pressure to a glue joint?

Clamping forces air out of the joint, brings the wood surfaces together evenly, and contributes to the strength of the glue line.

What methods are used to apply pressure to glue joints?

Clamps, nailing strips, power presses, brads, nails, and small screws.

What minimum curing temperature should be observed when joining wood with various adhesives?

70 degrees Fahrenheit or as specified by the glue manufacturer.

Why is it important to consider stains and discolored areas when inspecting wood structures?

Stains and discoloration usually accompany decay and/or rot.

What are the three principal types of welding?

Gas welding, electric arc welding, and electric resistance welding.

What are some advantages of gas shielded arc welding?

The weld is stronger, more ductile, and more corrosion resistant.

Which method of welding is less likely to cause buckling or warping of thin metal sheets?

Electric arc (or TIG) welding.

What is the purpose of shielding an arc weld with an inert gas?

The gas prevents atmospheric oxygen and/or nitrogen from contaminating the weld.

What is a common method of controlling expansion when welding a joint?

Place tack welds along the length of the joint.

What is the effect of inadequate penetration on a weld?

The weld will be weak.

What is the purpose of the flux used with brazing and silver soldering?

The flux cleans the base metal by removing any oxide film.

What type of flame is used when torch brazing or silver soldering?

A neutral flame.

What must be done to a soldering iron tip to increase the amount of heat transferred from the tip to the work?

The tip must be clean of all contaminants and properly tinned.

What is the preferred method for welding aluminum?

Tungsten Inert Gas (TIG) welding.

What precautions must be observed in order to weld titanium?

All traces of oxygen and nitrogen must be kept away from the weld area.

Describe one type of repair that could be made to a dented steel tube cluster joint.

A formed steel patch plate could be welded over the damaged area.

How can a soft flame be obtained without reducing the heat output of the torch?

Use a larger tip and adjust the gas pressure accordingly.

What factors determine the amount of heat delivered by a gas welding torch?

The size of the torch tip and the gas pressure.

What materials are aircraft covering fabrics made from?

Organic materials and synthetic materials.

How would you determine the strength requirements for fabric used to re-cover an aircraft?

The fabric must be of at least the quality and strength of the fabric used by the original manufacturer.

What two types of organic fibers are used for covering aircraft?

Cotton and linen.

What is meant by warp, weft, and bias in fabric?

Warp is the direction along the length of the fabric, weft is the direction across the fabric at right angles to the warp, and bias is a direction at a 45 degree angle to the warp and weft.

What is the purpose of the selvage edge on a roll of fabric?

It prevents the fabric from unraveling.

What identification marking is found on the selvage edge, and in which direction is the warp applied?

The FAA-PMA stamp is found on the selvage edge and the warp is applied parallel to the line of flight.

How are the fabric type and strength requirements determined for fabric-covered aircraft?

The original manufacturer determines the fabric type, and the strength requirements are a function of the never-exceed speed and wing loading.

What types of synthetic fibers are used for covering aircraft?

Fiberglass and heat-shrinkable polyester fibers.

Which type of fabric is unaffected by moisture and mildew?

Fiberglass.

What is the function or purpose of reinforcing tape?

Reinforcing tape is used between the fabric and the rib stitching to prevent the lacing cord from cutting through the fabric.

Where would you use surface tape?

Over rib stitching and sewed seams, over lapped edges, around corners, and along leading and trailing edges.

How should the edges of drainage, inspection, and ventilation holes be reinforced?

With plastic, aluminum, or brass grommets.

What are the principal methods used to test the condition of fabric?

Punch testers such as the Maule or Seybolt tester, and laboratory pull-testing.

What information is required before a cable rigging chart can be used?

The ambient temperature and the cable size

What is the function of a cable tension regulator?

It automatically adjusts the cable tension to compensate for expansion and contraction in the aircraft structure.

Describe the function of a rotorcraft collective pitch control.

Causes each rotor blade to change its pitch angle by the same amount, thus increasing or decreasing the lift produced by the rotor.

Decribe the function of a rotorcraft cyclic pitch control.

The cyclic control tilts the main rotor disc by changing the pitch angle of each rotor blade during its cycle of rotation, which causes the helicpter to move in the direction the rotor tilts.

What mechanism is most commonly used to compensate for the torque produced by the main rotor of a helicopter?

The tail rotor.

How is the amount of thrust produced by the tail rotor controlled?

By moving the foot pedals

Why should control surfaces be locked when an aircraft is parked?

To prevent damage from the wind.

What action is taken to prevent cracks from forming while dimpling magnesium or some hard sheet metals?

Hot dimpling equipment is used to preheat and soften the metal before the dimple is formed.

What type of damage can occur when using a rivet set that does not properly fit the rivet?

If too small, the rivet head may be damaged, and with an over-sized radius may cause damage to the sheet metal.

Why is it important to use the proper size weight buking bar when performing sheet metal riveting?

Too large or heavy will be difficult to control and may cause damage to the surrounding structure & too light will not properly upset the rivet before work hardening occurs.

What procedures should be followed to properly remove a solid-shank rivet?

Center punch the rivet and then drill just to the base of the rivet head with the same size or one size smaller drill. Once drilled, use a pin punch to tip off the rivet head and drive the remaining shank out of the hole while supporting the surrounding metal.

What are the two special calculations that must be made when bending sheet metal?

Bend allowance and setback.

What factors must be considered in order to determine setback?

The thickness of the metal and the bend radius.

What is done to a corner where two bends intersect to prevent cracking?

Relief holes are drilled in the corner.

What are the two reasons for installing a lightening hole in a sheet metal wing rib?

Lightening holes reduce the weight and increase stiffness.

Describe a joggle and explain its function.

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.

When repairing an all-metal aircraft, how do you determine what metals should be used?

Always use metal of the same type and thickness as the original structure.

Describe the acceptable methods used to repair elongated bolt holes found in a wooden wing spar.

Remove the section containing the elongated bolt holes and splice in a new section or replace the entire spar.

What type of joint is used to splice a solid or rectangular wood spar?

A scarf joint

What is the maximum number of splices allowed for any single spar?

Two

Describe the characteristics of a scarf joint.

The pieces are tapered or beveled on a slope of 1 to 10 or 1 to 12

Why must the beveled cut be accurate on both pieces of wood being repaired with a scarfed joint?

The two pieces must match exactly to ensure a tight glue joint.

What are the two primary uses for plywood in aircraft construction?

Gusset (or reinforcing) plates and aircraft skin.

Provide examples of at least 3 types of plywood skin repairs.

Splayed patches, surface patches, plug patches and scarfed patches.

What should be done to prevent a plywood patch and the pressure plate from sticking together if glue is extruded from the joint?

Place a piece of waxed paper or vinyl plastic between the patch and pressure plate

Why are lightweight steel bushings sometimes used in wooden structures?

Bushings prevent the wood from being crushed when bolts are tightened.

What is the purpose of large surface area washers when used on wooden structures?

Large washers provide additional bearing area for hardware to help preclude damage to the wood when the hardware is tightened.

Name several facings and core materials used in bonded honeycomb structures intended for special applications.

Stainless steel, titanium, magnesium, plywood, glass, nylon, and cotton cloth.

Describe the construction of a bonded honeycomb structure.

It is a laminated structure that has a solid facing bonded to either side of a core consisting of open, six-sided cells.

What must be done with a damaged area in a bonded honeycomb structure prior to beginning repairs?

The area must first be inspected to determine the damaged area before completely removing the damaged material.

A drill bit used for drilling composites should operate at approximately what speed?

Use an air-driven tool capable of a free speed of up to 20,000 rpm.

What are the most common causes for delamination of a composite structure?

Sonic vibration, expansion of internal moisture, liquid leakage and a manufacturing error.

What type of defect in, or damage to, a bonded honeycomb structure can be repaired using the potted repair method?

Filling a hole

Name some of the factors that cause crazing in transparent plastic windows and windshields?

Exposure to ultraviolet light, stress, solvents and improper handling

How should a hole be drilled in Plexiglas to avoid damage to the hole when the drill breaks through to the underside?

Back up the plastic with a piece of wood and feed the drill slowly.