Ice and Rain Control Systems Flashcards
7 cards from real Airframe Mechanic Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Ice and Rain Control Systems flashcards as text
Electrothermal ice protection systems on helicopter rotor blades typically use which power source?
Answer: Dedicated 400 Hz AC generators
Helicopter rotor blade heaters typically use 400 Hz AC power from dedicated generators to handle the high power demands of blade deicing.
What is 'runback ice' and why is it a concern?
Answer: Water melted by the anti-ice system that refreezes further aft on an unheated surface
Runback ice forms when melted water from a heated zone flows aft and refreezes on an unprotected surface, potentially creating a dangerous ridge.
Which component in a hot air wing anti-icing system regulates the temperature of bleed air delivered to the leading edge?
Answer: Precooler or mixing valve
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.
During a ground run-up, at what condition should wing thermal anti-ice normally NOT be operated for extended periods?
Answer: At high power settings with no airflow over the wings
Without airflow to cool the leading edge skins, extended ground operation of wing thermal anti-ice can cause overheating and structural damage.
What is the primary reason windshield anti-icing systems use a thin conductive coating or embedded resistance wires rather than bleed air?
Answer: Electrical systems provide uniform, controllable heating without disturbing vision
Electrical heating elements provide precise, even temperature distribution across the windshield without the optical distortion that hot air impingement could create.
A propeller electric deicing system shows uneven heating between blades. Which component is most likely at fault?
Answer: The slip ring and brush block assembly
The slip ring and brush assembly transfers electrical power from the stationary airframe to the rotating propeller; worn brushes or a dirty slip ring cause uneven or intermittent power delivery.
Which meteorological condition is most likely to produce clear (glaze) ice on an airframe?
Answer: Freezing drizzle with large supercooled water droplets just below 0°C
Freezing drizzle contains large supercooled droplets that spread and freeze slowly on impact, forming a clear, dense glaze ice layer.