Ice and Rain Control Systems

Question 1

What methods are used to supply heat for thermal anti-icing systems?

Answer 1

Turbine compressor hot air, engine exhaust heat exchangers and ram air heated by a combustion heater.

Question 2

How is the temperature maintained in a termal anti-icing system?

Answer 2

By mixing heated air with ambiente air.

Question 3

What happens to the termal anti-icing airflow after it has heated a leading edge surface?

Answer 3

The airflow is exhausted to the atmosphere

Question 4

How can an electrically heated pitot tube with an ammeter installed in the system be checked for operation?

Answer 4

It can be verified by noting the current consumption when the heater is turned on.

Question 5

What are two methods of inflating pneumatic deicer boots?

Answer 5

An engine-driven vacum pump and bleed air from a turbine-engine compressor.

Question 6

What normally keeps deicer boots held down in flight?

Answer 6

Suction is supplied to the boots during flight.

Question 7

What is the function of the oil separator used in some deicer boot systems?

Answer 7

Remove oil before it reaches the boots damaging the rubber.

Question 8

How are deicer boots attached to the leading edges of wing and tail surfaces?

Answer 8

Bonding, fairing strips and screws, or a combination of both.

Question 9

What must be accomplished to a deicer boot prior to a cold patch repair?

Answer 9

Relieve the installed tension.

Question 10

What is the purpose of the electronic timer in a pneumatic deicer boot system?

Answer 10

It controls the operating sequence and time intervals.

Question 11

Why is a windshield rain repelent system not operated when the windshield is dry?

Answer 11

Reduces visbility and its hard to remove when dry.

Question 12

Name at least two methods used to remove rain from a windshield:

Answer 12

Whipers, pneumatic blast, chemical rain repeler, hydrophobic seal coating.

Question 13

What powers windshield wiper systems?

Answer 13

Electrical or hydraulic Power.

Question 14

What are the two inherent problems associated with windshield wipers, when operated in flight?

Answer 14

(1)Aerodynamic forces reduce blade pressure (2) Failure to achieve fast enough wiper operations.

Question 15

How does a pneumatic rain removal system work?

Answer 15

The air blast breaks the rains drops into small particles that are then blow away.

Question 16

What prevents overheating of the leading edges of a thermal anti-ice system operated by engine bleed air?

Answer 16

Overheat sensors signal the anti-icing valves to close and shunt off the hot air.

Question 17

Why is it necessary to provide overheat protection for anti-icing systems that use turbine engine bleed air?

Answer 17

The air is too hot and can damage the aircraft estruture.

Question 18

What are the effects of arcing on an electrically heated windshield?

Answer 18

Localized overheating and damage to the windshield.

Question 19

Describe several potential problems associated with electrically heated windshields:

Answer 19

Arcing, delamination, scratches and discolorations.

Question 20

What important step should be taken prior to making a cold-patch repair to a deicer boot?

Answer 20

Consuslt the manufacturer’s service manual.

Question 21

Where would you find information on the acceptable limits of windshield delamination?

Answer 21

In the reference material provided by the manufacturer.