ice and rain controls systems

Name one of the most common anti-icing systems in use.

The most common anti-icing systems used are thermal pneumatic, thermal electric, and chemical.

Describe the operating principle of inflatable deicer boots.

Pneumatic deicing systems use rubber inflatable boots attached to the leading edge of the wings and stabilizers. During operation, the tubes are inflated with pressurized air and deflated in an alternating cycle.This inflation and deflation cause the ice to break off and it is carried away by the air stream. Both wings inflate and deflate at the same time.

Why is it critical to prevent the formation of ice on aircraft wings and control surfaces?

Ice formation distorts the shape of the wing and air flowing over it, reducing aerodynamic lift. Also, ice weighs the aircraft down, adding stress to the airframe.

What are two methods of inflating pneumatic deicer boots?

Pressurized air is provided by an engine driven air pump (vacuum pump), or by bleed air from the turbine engine compressor.

What methods are used to attach deicer boots to the leading edges of wing and tail surfaces?

They are attached by bonding to the surface with cement, fairing strips and screws, or a combination of both methods.

What is the purpose of an air-oil separator in a pneumatic deicing system?

The purpose of removing the oil from the air of the deicing system is to prevent deterioration of the rubber deicing boots, caused by contact with the oil.

What is used to clean deicer boots?

A mild soap and water solution.

What must be done before you can make a cold patch repair to a deicer boot?

Clean, rough the surface of the boot and patch, glue and attach.

What component of a pneumatic deicer system normally allows suction to be supplied to the boots to hold them down in flight?

the solenoid distributor valve.

Describe the operating principle for thermal anti-icing systems?

Thermal anti-icing systems are used primarily for the purpose of preventing ice from forming on the leading edges. However, they are designed to also deice the leading edges by supplying much hotter than normal air for short periods on a cyclic system. The airfoils that are to be protected are usually provided with closely spaced double skin. The hot air is passed through the space between skins, and the heat is sufficient to prevent formation of ice or to melt any ice next to the skin. The heated air is supplied continuously if the anti-icing system is turned on. Once used, this heated air is vented overboard through a hole in the leading edge.

How can you determine if the heater in a pitot is working?

Turn it on and feel for heat coming from it.

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

Bleed air from the turbine engine compressor, engine exhaust heat exchangers, and ram air heated by a combustion heaters

How is overheating prevented in a thermal anti-icing system using bleed air?

A thermal switch will cause a shut-off valve to close and stop the flow of bleed air when the temperature of the leading edge reaches approximately 185°F. When the temperature drops, the valve opens, and hot bleed air enters the wing once again.

what is the purpuse of the the de-ice boot electrical timers? ,

to inflate the boots symmetrically. or in the case of an electrical system to cycle each boot individually preventing an excessive load on the electrical system.

in a thermal anti-icing systems , what happens to the air after it has heated the leading edge of the wing ?

the air is exhausted to the atmosphere at the wingtip or at points where ice formation could be critical ?

What problems are associated with electrically heated windshields?

Delamination, arcing, scratches, and discoloration.

What is windshield delamination?

Delamination is the separation of the plies.

What does arcing usually indicate in an electrically heated windshield?

arcing usually indicates that there is a breakdown in the conductive coating.

Name the three methods of removing rain from aircraft windshields.

Wipers, pneumatic systems, and chemical repellant.

What type of power is used to operate windshield wiper systems?

Electrical or hydraulic power.

What are common problems encountered with windshield wipers?

One problem is the tendency of the aerodynamic forces to reduce the wiper blade loading pressure on the windshield which causes ineffective wiping or streaking. Another problem is achieving fast enough wiper oscillation.

How does a pneumatic rain removal system work?

This method uses high air pressure. The high temperature engine compressor bleed air is blown across the windshields, this air blast forms a barrier that prevents raindrops from striking the windshield surface.

Why should your windshield wipers not be operated when the windshield wipers are dry?

This can scratch the glass.