Airframe Mechanic Ice and Rain Control Systems Questions and Answers

Question 1

A turbine-powered aircraft's thermal anti-icing system for the wing leading edges is indicating a fault. The system uses engine bleed air. Which of the following is the most likely cause for the system to fail to operate correctly?

Accepted Answer

The anti-ice valve has failed to open.

Answer

Thermal anti-icing systems on turbine aircraft typically use hot bleed air from the engine's compressor section. This hot air is ducted to the leading edges of the wings and tail surfaces. A critical component in this system is the anti-ice valve, which controls the flow of bleed air. If this valve fails to open, hot air cannot reach the leading edges, rendering the system inoperative and triggering a fault indication.

Question 2

When inspecting a pneumatic de-icing boot, which condition would most likely require replacement of the boot rather than a repair?

Accepted Answer

Damage that exposes the underlying stitch-line threads.

Answer

While minor cracks, abrasions, and some punctures can often be repaired according to the manufacturer's instructions, damage that is severe enough to expose the internal stitch-line threads compromises the structural integrity of the boot. Such damage can lead to catastrophic failure of the boot during inflation and requires replacement.

Question 3

What is the primary principle of operation for chemical rain repellent systems on an aircraft windshield?

Accepted Answer

It creates a super-slick surface that prevents water from adhering, causing it to bead up and be blown away.

Answer

Chemical rain repellent works by applying a chemical film to the windshield. This film creates a hydrophobic surface, which significantly reduces the adhesion of water. As a result, raindrops that hit the windshield draw up into beads instead of spreading out, allowing the aerodynamic forces of the slipstream to easily blow them away, improving visibility.

Question 4

During an operational check of an electric windshield wiper system, the wipers operate correctly at both high and low speeds but fail to return to the 'park' position when the switch is turned off. Which component is most likely malfunctioning?

Accepted Answer

The park switch or associated circuit.

Answer

Aircraft windshield wiper systems have a mechanism to automatically return the blades to a parked position, out of the pilot's line of sight, when turned off. This is controlled by a dedicated park switch or a specific part of the control circuit. If the motor runs at normal speeds but fails to park, it indicates that the main motor is functional, but the circuit that should keep the motor running just until the blades are parked is faulty.

Question 5

Which of the following is a critical maintenance practice for pneumatic de-icing boots to ensure their longevity and proper function?

Accepted Answer

Regularly cleaning the boots with soap and water and performing visual inspections.

Answer

Proper care for pneumatic de-icing boots includes regular cleaning with approved mild soap and water to remove insects and contaminants that can degrade the rubber. This is followed by a thorough visual inspection for damage such as cracks, cuts, abrasions, or signs of delamination. This routine maintenance is crucial for identifying issues early and extending the service life of the boots.

Airframe Mechanic Certification Practice Test

Airframe Mechanic Certification Practice Test

Airframe Mechanic Ice and Rain Control Systems Questions and Answers