FAA Commercial Pilot Airplane (CAX)Aircraft SystemsMedium
Compared to a float-type carburetor, which of the following is an advantage of a fuel injection system on a reciprocating engine?
- AElimination of the need for a mixture control
- BSimplified engine construction requiring no fuel pump
- CAutomatic feathering of the propeller during engine failure
- DReduced susceptibility to induction icing since fuel is injected directly into the cylinders or intake ports rather than vaporized in a venturi
Show answer & explanationAnswer & explanation
Correct answer: D. Reduced susceptibility to induction icing since fuel is injected directly into the cylinders or intake ports rather than vaporized in a venturi
Float carburetors vaporize fuel in a venturi, which cools the incoming air and can cause carburetor icing even in relatively warm, humid conditions. Fuel-injected engines meter fuel directly to each cylinder or intake port, avoiding the venturi cooling effect and greatly reducing susceptibility to induction icing.
Why the other options are wrong
- A. Fuel-injected engines still use a mixture control to adjust fuel-to-air ratio.
- B. Fuel injection systems still require fuel pumps (engine-driven and/or electric boost pumps).
- C. Propeller feathering is unrelated to the fuel delivery system.
Fuel Injection vs. Carburetor
Fuel injection meters fuel directly into the cylinders or intake ports, avoiding the carburetor's venturi cooling effect and reducing susceptibility to induction icing.
- No venturi vaporization cooling
- Less prone to carburetor icing
- Still uses fuel pumps and mixture control
Memory trick: No venturi, no chill — injection skips the icing thrill.