Airframe Mechanic Aircraft Assembly and Rigging Questions and Answers

Question 1

After replacing a flight control cable, a technician must adjust its tension. Why is it critical to consider the ambient temperature when using a tensiometer?

Accepted Answer

The airframe and cable have different coefficients of thermal expansion.

Answer

Aircraft fuselages, typically made of aluminum alloy, expand and contract at a different rate than steel control cables when the temperature changes. Aircraft maintenance manuals provide temperature-tension charts to ensure the cable is tensioned correctly for a standard temperature (usually 70°F), regardless of the ambient temperature during adjustment. This ensures proper control feel and prevents flutter without overstressing the system at temperature extremes.

Question 2

A technician is performing a static balance check on an aileron that has just been repainted. The procedure involves supporting the aileron on a knife-edge fixture at its hinge line. Which of the following conditions indicates the aileron is properly balanced?

Accepted Answer

The aileron remains in a horizontal position or exhibits a slight nose-down tendency.

Answer

Proper static balance requires the control surface's center of gravity (CG) to be at or slightly ahead of the hinge line. When placed on a knife-edge at the hinge line, a balanced surface will remain horizontal or show a slight tendency to be nose-down. A trailing-edge-heavy condition (underbalance) is undesirable as it can lead to control surface flutter at high speeds.

Question 3

Which of the following is the primary purpose of incorporating dihedral in an aircraft's wing design?

Accepted Answer

To enhance lateral stability around the roll axis.

Answer

Dihedral is the upward angle of the wings from the horizontal. Its primary purpose is to provide positive lateral stability (stability in roll). When an aircraft with dihedral is disturbed and one wing drops, a sideslip occurs. This sideslip causes the lower wing to experience a greater angle of attack and generate more lift, creating a rolling moment that tends to restore the aircraft to a wings-level attitude.

Question 4

When safety wiring a turnbuckle using the double-wrap method, what is the generally accepted rule regarding the number of threads that may be exposed at either end of the barrel?

Accepted Answer

No more than three threads.

Answer

To ensure adequate thread engagement and structural integrity, standard aviation practice dictates that no more than three threads of the turnbuckle terminal should be exposed outside the barrel after tensioning and before safetying. This ensures the connection is strong enough to handle its rated load.

Question 5

A post-maintenance flight test reveals an aircraft has a persistent tendency to roll to the left. Before resorting to trimming devices, the mechanic should perform which of the following rigging checks?

Accepted Answer

A symmetry and incidence check of the wings.

Answer

A tendency to roll indicates an asymmetry in the lift being produced by the wings. This can be caused by improper wing rigging, where one wing has a slightly different angle of incidence (the angle at which the wing is attached to the fuselage) or if the wings are not symmetrical with respect to the aircraft's longitudinal axis. A symmetry and incidence check is required to verify and correct these angles.

Airframe Mechanic Certification Practice Test

Airframe Mechanic Certification Practice Test

Airframe Mechanic Aircraft Assembly and Rigging Questions and Answers