Airframe Mechanic Flight Control Systems Questions and Answers

Question 1

After a minor repair and repainting of an aileron, what procedure is critical to perform to prevent a potentially catastrophic in-flight failure?

Accepted Answer

Re-balancing the control surface.

Answer

Adding or removing material, such as paint or body filler, can change the weight distribution of a control surface. If the center of gravity shifts aft of the hinge line, it can lead to aerodynamic flutter at high speeds, which is a rapid, uncontrolled oscillation that can destroy the surface and lead to loss of the aircraft. Re-balancing ensures the center of gravity is correctly located relative to the hinge line.

Question 2

A technician is rigging the flight controls of an aircraft and notes that for a left roll command, the left aileron moves 20 degrees up, while the right aileron moves 15 degrees down. What is this design feature called and what is its primary purpose?

Accepted Answer

Differential aileron travel; to counteract adverse yaw.

Answer

This is called differential aileron travel. The downward-deflected aileron creates more lift and, as a byproduct, more drag than the upward-deflected aileron. This drag imbalance can cause the aircraft's nose to yaw in the opposite direction of the turn (adverse yaw). By having the up-going aileron travel a greater distance, its drag is increased, helping to equalize the drag on both wings and create a more coordinated turn.

Question 3

Which of the following are all considered primary flight controls?

Accepted Answer

Ailerons, elevator, and rudder.

Answer

Primary flight controls are those required to safely control the aircraft's movement about its three principal axes: pitch, roll, and yaw. The elevator controls pitch (lateral axis), ailerons control roll (longitudinal axis), and the rudder controls yaw (vertical axis). Flaps, slats, spoilers, and trim tabs are considered secondary controls.

Question 4

In a fly-by-wire (FBW) system, what is the primary function of the Flight Control Computer (FCC)?

Accepted Answer

To process pilot inputs and sensor data, then command actuators to move control surfaces.

Answer

In a fly-by-wire system, the mechanical linkages are replaced by an electronic interface. The Flight Control Computer (FCC) is the brain of this system. It receives electrical signals from the pilot's controls, combines this with data from various aircraft sensors (like airspeed, attitude, etc.), and then sends calculated electrical commands to the actuators that move the flight control surfaces.

Question 5

The primary purpose of an elevator trim tab is to:

Accepted Answer

Relieve the pilot of the need to maintain constant pressure on the control column.

Answer

A trim tab is a small, adjustable surface on the trailing edge of the elevator. By deflecting the trim tab, the pilot creates a small aerodynamic force that holds the main elevator in a position to maintain a desired flight attitude (e.g., level flight, climb, or descent). This allows the pilot to fly 'hands-off' without continuously applying forward or backward pressure on the yoke.

Airframe Mechanic Certification Practice Test

Airframe Mechanic Certification Practice Test

Airframe Mechanic Flight Control Systems Questions and Answers