Ice and Rain Control Systems

Question 1

Why is it important that ice not be allowed to build up on airplane wings in flight?

Answer 1

Ice distorts the shape of the airfoil and destroys the aerodynamic lift. The weight of the ice loads the aircraft down.

Question 2

What is the function of an ice detector when ice is detected?

Answer 2

To illuminate an annunciator light in the flight deck and, in some aircraft, to automatically turn on anti-icing systems.

Question 3

How is ice kept from forming on the pitot tube of an airplane?

Answer 3

Pitot tubes are heated by electric current flowing through heater elements built into them.

Question 4

How is ice prevented from forming on the windshield of modern jet transport airplanes?

Answer 4

The windshield has a heater element embedded in it. Electric current heats the windshield and keeps ice from forming on it.

Question 5

Are pneumatic deicer boots operated before ice forms or after it has formed?

Answer 5

Pneumatic deicer boots are not operated until ice has formed over them. When the boot inflates, it breaks the ice, and the air flowing over the airfoil blows it away.

Question 6

Where does the air come from to operated the pneumatic deicer boots on a reciprocating-engine powered airplance?

Answer 6

From the discharge side of the air pump used to operate the gyro instruments.

Question 7

What is meant by a wet vacuum pump used to power pneumatic deicer boots?

Answer 7

It is a vacuum pump that uses engine oil to lubricate its steel vanes. A dry vacuum pump uses carbon vanes, and it does not require any oil for lubrication.

Question 8

What is the purpose of the oil separator in a deicer system?

Answer 8

Oil separators are used with wet vacuum pumps to remove the lubricating oil from the discharge air before this air is used in the deicer boots.

Question 9

How are rubber deicer boots cleaned?

Answer 9

By washing them with mild soap and water.

Question 10

how are rubber deicer boots attached to the leading edges of aircraft wings and tail surfaces?

Answer 10

They are bonded to the surface with an adhesive. Boots on the older aircraft were attach with machine screws and Rivnuts.

Question 11

What is the sequence of inflation of a deicing boot system?

Answer 11

There are three tubes in a deicer boot, upper, center, and lower. The center tube inflates first with upper and lower tubes a specified number of seconds later.

Question 12

When should rain repellent be used on an airplane windshield?

Answer 12

Only when the windshield is wet with rain.

Question 13

Where can you find the instructions for adjusting the tension for the windshield wiper blades?

Answer 13

In the aircraft maintenance manual.

Question 14

How can you tell, on a preflight inspection, that the pitot heater is operating?

Answer 14

Turn it on for about a minute and then on the walk-around inspection, feel it to see that is warm.

Question 15

Where can you find the correct part number for the electrically heated pitot head used on an aircraft?

Answer 15

In the illustrated parts manual for the aircraft.

Question 16

If the pitot head includes ports for the static air system, what must be done after the head is replaced?

Answer 16

A static system leak test must be performed and the results recorded in the aircraft maintenance records.

Question 17

How can you test if the pitot heat is working?

Answer 17

Briefly turn the pitot heat system on and observe an increased current indication on the ammeter.

Question 18

What might be likely causes for a propeller electrothermal deicer system failure?

Answer 18

A tripped circuit breaker or broken wire to the electrical heating elements.

Question 19

How can a pilot determine if an electrothermal propeller deicer is working?

Answer 19

The pilot should observe an increased ammeter reading when the system is energized.

Question 20

What are two ways rain can be kept from obstructing the pilot’s vision through the windshield or an airplane?

Answer 20

The rain can be blown away by a high velocity blast of compressor bleed air, or it can be wiped away with electrically or hydraulically operated windshield wipers.

Question 21

What risks are associated with testing and maintenance of ice control system?

Answer 21

Running windshield wipers on a dry windshield can damage the windshield. Over-pressurizing deice boots with a ground test system can damage the boots. Follow the maintenance manual procedures whenever testing or servicing ice control systems.

Question 22

What are the dangers of improper handling and storage of deicing fluids?

Answer 22

Deice fluids can be hazardous to health and the environment. Always follow the manufacturer’s recommendations for handling and storage.

Question 23

What are the risks associated with using incorrect cleaning materials on heated windshields?

Answer 23

Using the incorrect cleaning materials can damage windshields and reduce visibility through the windshield. Follow the maintenance manual procedures for cleaning heated windshields.