FAA Aviation Mechanic Airframe (AMA)Fuel, Cabin and Ice Control SystemsMedium
A pneumatic deicer boot system on a reciprocating engine aircraft is being tested on the ground. What component sequences the inflation and deflation of the individual boot sections during operation?
- ADistributor valve
- BEjector nozzle
- CPressure relief valve
- DIce rate meter
Show answer & explanationAnswer & explanation
Correct answer: A. Distributor valve
The distributor valve times and sequences air pressure to inflate and deflate the leading edge boot sections in a controlled pattern, cracking off accumulated ice.
Why the other options are wrong
- B. Ejector nozzles are used for vacuum-driven instruments, not deicer boot sequencing.
- C. A pressure relief valve limits maximum system pressure, it does not sequence boots.
- D. An ice rate meter senses ice accumulation, it does not control the boots directly.
Pneumatic Deicer Boot Distributor Valve
A timed valve in a pneumatic deicing system that directs pressurized air sequentially to different sections of rubber boots to inflate and deflate them, breaking off ice.
- Powered typically by an engine-driven vacuum/pressure pump
- Boots inflate in a specific sequence to avoid ice bridging
- Deflated by vacuum between cycles for aerodynamic smoothness
Memory trick: Distributor valve is the boot system's traffic cop.