Airframe Chapter 13 Flashcards
What controls the temperature in a thermal anti icing system?
Heat and cold air are mixed.
What are the sources of heat for thermal anti icing systems.
Bleed air from the compressor section of a turbine engine, engine exhaust heat exchangers and combustion heaters.
What prevents overheating of the leading edge of a thermal anti ice system operated by engine bleed air?
Overheat sensors signal the anti icing valves to close and shut off the hot air.
What happens to the hot air used by a thermal anti ice system after it has heated the surface?
The air is dumped overboard.
Why is it necessary to provide overheat protection for anti icing systems that use turbines engine bleed air?
The air is hot enough to cause damage to the aircraft structure.
What are the effects of arcing on an electrically heated windshield?
Localized overheating and damage to the windshield.
Can the operation of an electrically heated pitot tube be checked with the aircraft’s ammeter, and if so, how?
Yes, turn the pitot heater on and observe the deflection of the ammeter needle.
Describe several potential problems associated with electrically heated windshields.
Arcing, delamination, scratches, and discoloration.
Why do some pneumatic de-icer boot systems have an electrically operated timer?
To automatically cycle the boots, provide the proper rest time, and then recycle the boots.
What are the two common methods of inflating pneumatic de-icer boots?
Bleed air from a turbine engine or exhaust from an engine driven vacuum pump.
What procedure is used to hold deicer boots flat with the airfoil surface during flight?
Suction is applied to the boots.
Why do some deicer boot systems incorporate an oil separator?
If a wet pump system is used, the oil must be removed before it reaches the boots because oil damages the rubber.
What method are used to attach a deicer boot to the leading edges of the wing and tail surfaces?
Adhesives, fairing strips and screws, or a combination of both.
What important step should be taken prior to making a cold patch repair to a deicer boot?
Consult the manufacturer’s service manual and follow the repair instructions explicitly.
Describe the methods commonly used to remove rain from a windshield.
Windshield wipers, a blast of air, or chemical rain repellant.
What power sources are used to operate windshield wipers?
Electrical or hydraulic pressure.
Name the two problems associated with in flight operation of aircraft windshield wipers.
Insufficient blade pressure caused by aerodynamic forces and failure to oscillate fast enough.
Describe the operation of a pneumatic rain removal system.
A high velocity air blast prevents the rain from reaching the surface of the windshield.
What are the effects of spraying rain repellant on a dry windshield?
It smears and streaks, which reduces visibility, and it is hard to remove when dry.
Where would you find information on the acceptable limits of windshield delamination?
In the reference material provided by the manufacturer.
