Airframe Oral Exam Questions with Correct Answers
1. What is the function of a vortex generator?Answer: It is designed to delay or prevent separation of the boundary
layer.Explanation: Vortex generators create controlled turbulence, energizing the boundary layer and preventing flow
separation, which improves lift and stall characteristics.
2. What are the three axes of an airplane?Answer: Longitudinal, lateral, and vertical.Explanation: These axes represent the
airplane’s three-dimensional movement: roll around the longitudinal axis, pitch around the lateral axis, and yaw around the
vertical axis.
3. What are the three primary flight controls of an aircraft?Answer: Ailerons, elevator, and rudder.Explanation: These controls
manage roll, pitch, and yaw respectively, enabling the pilot to control the aircraft’s attitude and direction.
4. Name several secondary flight controls and describe their general purpose.Answer: Balance tabs, anti-servo tabs, servo tabs,
and spring tabs; they assist in control movement and trimming the aircraft for hands-off flight.
5. Name several types of auxiliary flight controls and describe their general purpose.Answer: Leading and trailing edge flaps,
slats, slots, and speed brakes; used during low-speed flight to increase lift or reduce speed.
6. What is a servo trim tab?Answer: An auxiliary control positioned by the pilot that creates aerodynamic forces to assist in
moving a control surface, reducing pilot effort.
7. What is a spring tab?Answer: An auxiliary control that aids control surface movement at high speeds when control forces
are high, by using a spring mechanism.
8. What is a balance trim tab?Answer: An auxiliary control that creates aerodynamic forces to help move a control surface,
connected via a control rod to the fixed surface.
9. What are the four most common types of high-lift devices?Answer: Leading edge flaps, trailing edge flaps, slats, and slots.
10. Describe some tools used to check control surface travel.Answer: Universal propeller protractor or specialized control
surface protractor.
11. Name three mechanical methods by which flight control systems may be actuated.Answer: Cables, push-pull rods, and
torque tubes.
12. What is a fairlead?Answer: A device that prevents a control cable from rubbing on the aircraft structure.
,13. What are the most likely places for a control cable to wear or break?Answer: Over pulleys or through fairleads where
bending or friction occurs.
14. What information is required before a cable rigging chart can be used?Answer: Ambient temperature and cable size.
15. What is the function of a cable tension regulator?Answer: It automatically adjusts cable tension to compensate for thermal
expansion and contraction in the aircraft structure.
16. Describe the function of a rotorcraft collective pitch control.Answer: It causes all rotor blades to change pitch angle
equally, increasing or decreasing lift.
17. Describe the function of a rotorcraft cyclic pitch control.Answer: Tilts the main rotor disc by changing the pitch of
individual blades during rotation, controlling the helicopter’s direction.
18. What mechanism most commonly compensates for main rotor torque?Answer: The tail (or anti-torque) rotor.
19. How is the thrust of the tail rotor controlled?Answer: By the pilot’s foot pedals, which tilt the tail rotor blades.
20. Why should control surfaces be locked when an aircraft is parked?Answer: To prevent damage from wind or unintended
movement.
21. What is the major type of damage to aluminum structures caused by weather?Answer: Corrosion.
22. Name several methods for forming sheet metal.Answer: Bending, folding, stretching, shrinking, bumping, and crimping.
23. What are the dimensions of a properly formed rivet head?Answer: About 1.5 times the shank diameter in width and half
the shank diameter in height.
24. Describe the markings on rivet heads:
A rivet with no mark: Plain
B rivet: Cross mark
D rivet: Raised dot
AD rivet: Dimple
DD rivet: Double dash
25. What happens to the stem of a self-plugging rivet during installation?Answer: The stem is pulled until it snaps off, then
,trimmed flush with the head.
26. Name at least three types of self-plugging mechanical lock rivets.Answer: CherryMax, CherryLock, Huck, Olympic-locks.
27. What's the difference between tools for CherryLock and CherryMax rivets?Answer: CherryLock requires different tools for
different sizes and head shapes; CherryMax uses one tool for all sizes.
28. Which stress is most common in rivet failure?Answer: Shear stress.
29. How do you determine the size when replacing a 2024 rivet with a 2117 rivet?Answer: Use the next larger size (e.g.,
5/32"), assuming minimum edge distance and spacing are met.
30. How do you determine the total length of a solid rivet?Answer: Grip length + 1.5 times the rivet diameter.
31. What minimum edge distance and spacing are recommended for single row of protruding head rivets?Answer: At least 2
diameters from the edge and 3 diameters apart.
32. How do you decide whether to dimple or countersink for flush rivets?Answer: Based on the sheet thickness; thin sheets are
dimpled, thick sheets are countersunk.
33. How to prevent cracks when dimpling magnesium or hard sheet metals?Answer: Use hot dimpling equipment to preheat
and soften the metal.
34. What damage can occur if the rivet set does not fit properly?Answer: Damage to the rivet head or sheet metal; too small
causes deformation, too large causes damage.
35. Why use the proper size and weight bucking bar?Answer: To control force, avoid damage, and ensure proper upset of the
rivet.
36. How to remove a solid-shank rivet?Answer: Center punch, drill to the rivet head, then use a pin punch to drive out the
shank.
37. Two special calculations when bending sheet metal?Answer: Bend allowance and setback.
38. Factors to consider for setback?Answer: Metal thickness and bend radius.
39. How do you prevent cracking at a corner where two bends intersect?Answer: Drill relief holes.
40. Why install lightening holes in a wing rib?Answer: To reduce weight and increase stiffness.
41. Describe a joggle and its function:Answer: An offset formed at intersecting sheets to allow stacking and assembly.
42. How to determine what metals to use for repair?Answer: Use the same type and thickness as the original.
1. What is the function of a vortex generator?Answer: It is designed to delay or prevent separation of the boundary
layer.Explanation: Vortex generators create controlled turbulence, energizing the boundary layer and preventing flow
separation, which improves lift and stall characteristics.
2. What are the three axes of an airplane?Answer: Longitudinal, lateral, and vertical.Explanation: These axes represent the
airplane’s three-dimensional movement: roll around the longitudinal axis, pitch around the lateral axis, and yaw around the
vertical axis.
3. What are the three primary flight controls of an aircraft?Answer: Ailerons, elevator, and rudder.Explanation: These controls
manage roll, pitch, and yaw respectively, enabling the pilot to control the aircraft’s attitude and direction.
4. Name several secondary flight controls and describe their general purpose.Answer: Balance tabs, anti-servo tabs, servo tabs,
and spring tabs; they assist in control movement and trimming the aircraft for hands-off flight.
5. Name several types of auxiliary flight controls and describe their general purpose.Answer: Leading and trailing edge flaps,
slats, slots, and speed brakes; used during low-speed flight to increase lift or reduce speed.
6. What is a servo trim tab?Answer: An auxiliary control positioned by the pilot that creates aerodynamic forces to assist in
moving a control surface, reducing pilot effort.
7. What is a spring tab?Answer: An auxiliary control that aids control surface movement at high speeds when control forces
are high, by using a spring mechanism.
8. What is a balance trim tab?Answer: An auxiliary control that creates aerodynamic forces to help move a control surface,
connected via a control rod to the fixed surface.
9. What are the four most common types of high-lift devices?Answer: Leading edge flaps, trailing edge flaps, slats, and slots.
10. Describe some tools used to check control surface travel.Answer: Universal propeller protractor or specialized control
surface protractor.
11. Name three mechanical methods by which flight control systems may be actuated.Answer: Cables, push-pull rods, and
torque tubes.
12. What is a fairlead?Answer: A device that prevents a control cable from rubbing on the aircraft structure.
,13. What are the most likely places for a control cable to wear or break?Answer: Over pulleys or through fairleads where
bending or friction occurs.
14. What information is required before a cable rigging chart can be used?Answer: Ambient temperature and cable size.
15. What is the function of a cable tension regulator?Answer: It automatically adjusts cable tension to compensate for thermal
expansion and contraction in the aircraft structure.
16. Describe the function of a rotorcraft collective pitch control.Answer: It causes all rotor blades to change pitch angle
equally, increasing or decreasing lift.
17. Describe the function of a rotorcraft cyclic pitch control.Answer: Tilts the main rotor disc by changing the pitch of
individual blades during rotation, controlling the helicopter’s direction.
18. What mechanism most commonly compensates for main rotor torque?Answer: The tail (or anti-torque) rotor.
19. How is the thrust of the tail rotor controlled?Answer: By the pilot’s foot pedals, which tilt the tail rotor blades.
20. Why should control surfaces be locked when an aircraft is parked?Answer: To prevent damage from wind or unintended
movement.
21. What is the major type of damage to aluminum structures caused by weather?Answer: Corrosion.
22. Name several methods for forming sheet metal.Answer: Bending, folding, stretching, shrinking, bumping, and crimping.
23. What are the dimensions of a properly formed rivet head?Answer: About 1.5 times the shank diameter in width and half
the shank diameter in height.
24. Describe the markings on rivet heads:
A rivet with no mark: Plain
B rivet: Cross mark
D rivet: Raised dot
AD rivet: Dimple
DD rivet: Double dash
25. What happens to the stem of a self-plugging rivet during installation?Answer: The stem is pulled until it snaps off, then
,trimmed flush with the head.
26. Name at least three types of self-plugging mechanical lock rivets.Answer: CherryMax, CherryLock, Huck, Olympic-locks.
27. What's the difference between tools for CherryLock and CherryMax rivets?Answer: CherryLock requires different tools for
different sizes and head shapes; CherryMax uses one tool for all sizes.
28. Which stress is most common in rivet failure?Answer: Shear stress.
29. How do you determine the size when replacing a 2024 rivet with a 2117 rivet?Answer: Use the next larger size (e.g.,
5/32"), assuming minimum edge distance and spacing are met.
30. How do you determine the total length of a solid rivet?Answer: Grip length + 1.5 times the rivet diameter.
31. What minimum edge distance and spacing are recommended for single row of protruding head rivets?Answer: At least 2
diameters from the edge and 3 diameters apart.
32. How do you decide whether to dimple or countersink for flush rivets?Answer: Based on the sheet thickness; thin sheets are
dimpled, thick sheets are countersunk.
33. How to prevent cracks when dimpling magnesium or hard sheet metals?Answer: Use hot dimpling equipment to preheat
and soften the metal.
34. What damage can occur if the rivet set does not fit properly?Answer: Damage to the rivet head or sheet metal; too small
causes deformation, too large causes damage.
35. Why use the proper size and weight bucking bar?Answer: To control force, avoid damage, and ensure proper upset of the
rivet.
36. How to remove a solid-shank rivet?Answer: Center punch, drill to the rivet head, then use a pin punch to drive out the
shank.
37. Two special calculations when bending sheet metal?Answer: Bend allowance and setback.
38. Factors to consider for setback?Answer: Metal thickness and bend radius.
39. How do you prevent cracking at a corner where two bends intersect?Answer: Drill relief holes.
40. Why install lightening holes in a wing rib?Answer: To reduce weight and increase stiffness.
41. Describe a joggle and its function:Answer: An offset formed at intersecting sheets to allow stacking and assembly.
42. How to determine what metals to use for repair?Answer: Use the same type and thickness as the original.
