17.5 Ice Protection Flashcards
What are the effects of ice formation on a propeller?
Ice formation produces a distortion to the aerofoil section, vibrations, and lower propeller efficiency.
When is icing protection necessary for propellers?
Icing protection is necessary when an aircraft is flying under icy conditions to prevent ice build-up on the propeller blades.
What areas of the aircraft are most at risk from icing?
The regions most at risk from icing are the propeller blades, the spinner, and the engine air intake.
At what ambient air temperatures can icing occur?
Icing can occur at ambient air temperatures up to +10° when visible moisture is present in the air.
What are the two main ice protection methods for propellers?
The two main ice protection methods are the fluid anti-icing system and the electrical de-icing system.
What is the purpose of an anti-icing system?
Anti-icing systems are activated before the formation of ice on the propeller.
What is the function of a de-icing system?
Electric de-icing systems can provide ice protection for the entire duration of the flight, if necessary.
Where is fluid anti-icing equipment generally found?
This type of system is generally found only on piston-engined aircraft.
What fluid is commonly used in fluid anti-icing systems?
An alcohol-based fluid (Iso-Propyl-Alcohol) is commonly used.
What are the disadvantages of fluid anti-icing systems?
Disadvantages include the weight of the fluid, constant monitoring of fluid levels, operation before icing occurs, and inability to remove impacted ice.
What maintenance is required for fluid anti-icing equipment?
Maintenance includes ensuring nozzle alignment, conducting flow tests, functional tests, regular cleaning, and inspections.
What components are part of an electrical de-icing system?
An electrical de-icing system consists of an electrical energy source, a resistance heating element, system controls, and necessary wiring.
How is electrical power transferred in an electrical de-icing system?
Electrical power is transferred through electrical leads to slip rings and brushes on the propeller hub.
What is the purpose of cyclic heating in electrical de-icing systems?
Cyclic heating is used to lessen the load on the aircraft electrical system and prevent run-back conditions.
What are the two cycles used in electrical de-icing systems?
The fast cycle lasts approximately 2 minutes for temperatures from +10 °C to -6 °C, and the slow cycle lasts approximately 6 minutes for temperatures below -6 °C.
