Airframe Mechanic Certification Ice and Rain Control Systems 3

Question 1

Electrothermal ice protection systems on helicopter rotor blades typically use which power source?

Accepted Answer

Dedicated 400 Hz AC generators

Answer

Helicopter rotor blade heaters typically use 400 Hz AC power from dedicated generators to handle the high power demands of blade deicing.

Question 2

What is 'runback ice' and why is it a concern?

Accepted Answer

Water melted by the anti-ice system that refreezes further aft on an unheated surface

Answer

Runback ice forms when melted water from a heated zone flows aft and refreezes on an unprotected surface, potentially creating a dangerous ridge.

Question 3

Which component in a hot air wing anti-icing system regulates the temperature of bleed air delivered to the leading edge?

Accepted Answer

Precooler or mixing valve

Answer

A precooler or mixing valve blends hot bleed air with cooler air (or ambient) to maintain the leading edge at an effective but safe temperature.

Question 4

During a ground run-up, at what condition should wing thermal anti-ice normally NOT be operated for extended periods?

Accepted Answer

At high power settings with no airflow over the wings

Answer

Without airflow to cool the leading edge skins, extended ground operation of wing thermal anti-ice can cause overheating and structural damage.

Question 5

What is the primary reason windshield anti-icing systems use a thin conductive coating or embedded resistance wires rather than bleed air?

Accepted Answer

Electrical systems provide uniform, controllable heating without disturbing vision

Answer

Electrical heating elements provide precise, even temperature distribution across the windshield without the optical distortion that hot air impingement could create.

Airframe Mechanic Certification Practice Test

Airframe Mechanic Certification Practice Test

Airframe Mechanic Certification Ice and Rain Control Systems 3