FAA Aviation Mechanic Powerplant (AMP)PropellersMedium
A technician services a fluid propeller ice-protection system that uses isopropyl alcohol distributed through a slinger ring mounted at the rear of the spinner. How does the anti-icing fluid ultimately reach the leading edge of each blade?
- APitot pressure forces the fluid through internal tubing to the tips
- BEngine bleed air pressure atomizes the fluid at the blade tips
- CElectric heating elements vaporize the fluid so it condenses on the blade surfaces
- DCentrifugal force throws the fluid outward through feed shoes onto the blade leading edges
Show answer & explanationAnswer & explanation
Correct answer: D. Centrifugal force throws the fluid outward through feed shoes onto the blade leading edges
In a fluid (alcohol) propeller deicing system, fluid is fed to a rotating slinger ring, and centrifugal force throws it outward through tubing and feed shoes bonded to each blade's leading edge, where it flows spanwise to prevent ice formation. Electric heating, bleed air, and pitot pressure are not part of this fluid-based system.
Why the other options are wrong
- A. Pitot pressure is unrelated to propeller deicing fluid delivery.
- B. Bleed air atomization is not used in propeller fluid anti-ice systems.
- C. Vaporization/electric heating describes electrothermal systems, not fluid systems.
Fluid (Alcohol) Propeller Anti-Ice System
A propeller ice protection system that pumps isopropyl alcohol to a rotating slinger ring, where centrifugal force distributes it through feed shoes to the blade leading edges to prevent ice buildup.
- Uses isopropyl alcohol fluid
- Slinger ring rotates with spinner/hub
- Centrifugal force distributes fluid outward
- Feed shoes bonded to blade leading edges
Memory trick: Spin the ring, fling the fluid — alcohol races out to the blade edges.