In-flight Icing Conditions Quiz

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What happens to the contacts when ice forms on the diaphragm?

They close, supplying current to an ice warning light and a heater. (correct)

They short-circuit, activating the rotor-driven motor.

They become non-functional until the ice melts.

They open, causing the crew to take de-icing action.

What is the purpose of the heater in the probe mentioned in the text?

To melt any ice formed on the probe. (correct)

To activate the micro-switch for the warning light.

To enhance the current draw of the electric motor.

To increase pressure on the diaphragm.

How is a warning light signal activated in case enough ice forms on the rotor?

By decreasing the motor speed.

By increasing the motor torque and twisting it slightly. (correct)

By turning off the detection probe heater.

By activating the diaphragm contacts.

Why does ice forming on the rotor cause an increase in motor torque?

To shave off the formed ice. Signup and view all the answers

How is icing cessation detected in relation to the rotor-driven motor?

By sensing an increase in current draw. Signup and view all the answers

What happens when the drum slows down and draws more current?

The current draw is sensed by a current metre. Signup and view all the answers

What source of power is used to supply the drain mast heater circuit when the ground handling bus is powered?

42.5 volts AC from the drain mast heater transformer Signup and view all the answers

What happens to the windshield wipers on the aircraft when the windshield is dry?

They stop working to avoid damaging the windshield Signup and view all the answers

Which motor type is NOT commonly used to power aircraft windshield wipers?

Steam motor Signup and view all the answers

What voltage is supplied to the heaters of the drain mast when the aircraft is in operation?

115 volts AC from the ground service transfer bus Signup and view all the answers

What is the purpose of ensuring that the windshield is clear of foreign matter before operating the wipers?

To prevent damage to the windshield Signup and view all the answers

Which relays control the supply of power to the drain mast heaters when power is provided to the main airplane buses?

R8277 and R731 Signup and view all the answers

What is the purpose of inflating the de-ice boots on an aircraft?

To break the ice by protruding out Signup and view all the answers

How long do the de-ice boots inflate for during a 'cold' sequence?

6 seconds Signup and view all the answers

What is the timeframe for deflating the de-ice boots in a 'warm' sequence?

2 minutes and 54 seconds Signup and view all the answers

How should de-icer boots be cleaned according to the text?

Using mild soap and water Signup and view all the answers

What is used to remove oil and grease from the surface of de-icer boots?

White spirit or lead-free gasoline Signup and view all the answers

Why is it important to keep de-icer boots clean?

To prevent damage to the aircraft surface Signup and view all the answers

Where are the worst continuous icing conditions typically found?

In stratified clouds near the freezing level Signup and view all the answers

At what altitude range do most catastrophic in-flight icing accidents occur?

Between 3,700 m and 4,900 m ASL Signup and view all the answers

In which type of clouds can structural icing occur at altitudes above 30,000 ft?

Cumuliform clouds with strong updrafts Signup and view all the answers

What is the main reason that icing is rare above altitudes of 16,000 ft?

Cloud droplets at those altitudes are already frozen Signup and view all the answers

What is a characteristic of glaze or clear ice?

It is transparent and smooth Signup and view all the answers

What can distort the freezing level in cumuliform clouds causing severe icing potential?

Both strong updrafts and downdrafts Signup and view all the answers

What component changes the rotary motion of the motor to the oscillating motion required by the wiper blades?

Converter Signup and view all the answers

Which part determines the stroke arc of the wiper blades?

Converter Signup and view all the answers

What part keeps the wiper blade vertical and governs the wiper pattern?

Guide arm Signup and view all the answers

How is the spring tension against the windshield obtained?

Using a steel pin inserted through a pinhole in the arm Signup and view all the answers

What supports the end of the guide arm?

Pivot stud Signup and view all the answers

How can one remove the wiper for maintenance?

Inserting a 1/8-inch-diameter steel pin through a pinhole in the arm Signup and view all the answers