Carburetor icing leads to off-airport landing

Aircraft: Cessna 172. Injuries: None. Location: Springfield, Tenn. Aircraft damage: Substantial.

What reportedly happened: The pilot was on the second leg of a VFR cross-country flight. He was flying at an altitude of 3,500 feet in order to remain below an overcast ceiling.

When he was 10 miles from the airport he began configuring the airplane for landing. He reduced engine power to about 1,500 rpm, set the mixture to full rich, but did not activate the carburetor heat. The engine lost power.

He performed a forced landing in a field. During the landing roll, the nose landing gear struck a ditch.

Responders noted that fuel was recovered from the airplane following the accident. The engine was run after the accident with no anomalies noted.

The temperature and dew point reported on the surface at an airport located about 21 nautical miles from the accident site were conducive to carburetor icing at both glide and cruise power settings.

Probable cause: The pilot did not apply carburetor heat during approach to landing, which resulted in a total loss of engine power due to carburetor icing.

NTSB Identification: ERA12LA148

This January 2012 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.


  1. Mack says

    Ten miles out is too far from the airport to configure a landing. The runway should be in “striking” distance before reducing power for the approach.

    • says

      Mack; Agree – and if this dude was flying a 170 knt Bonanza, rest assures he would have lowered the gear (and flaps?) 20 mi from the airport, and then “dragged” it to the downwind at 120 knts – guess he wanted to be WELL ahead of the machine!

  2. Wayne says

    Carb heat BEFORE power reduction, carb heat cold AFTER full power applied, if go round, or AFTER landing. As per the aircraft manual. You then get full benefit of carb heat.

    Thank goodness, your Aviation Authority, not mine, has gone “bananas” reducing sim time for IF training? That is certainly a step backwards. We used to look to FAA for guidance, oops, just “lost” me.

  3. PB says

    Students are taught to apply full rich mixture, and carbie heat under certain conditions.
    But they aren’t taught why they should apply full rich. They are told various stories, and I wonder if instructors know themselves.
    The first reason is to have adequate power as one descends and the pilot should richen the mixture as one descends. The other is to have full rich for engine cooling purposes and full power in case a go around is required.
    In this case, the pilot went full rich at a reduced power setting and flooded the engine, exacerbated by the carb icing which further reduced the air intake.
    Low time pilots need to be taught that mixture is richened, not the engine flooded. Under a lot of circumstances it may be inappropriate to go full rich, as in this case.

  4. Tom says

    Apply carb heat before power reduction,
    Or end up with carburetor ice,
    And don’t forget sleep apnea’s seduction,
    FAA takes your medical oh so nice.

    • Howard says

      Sorry , heat before power reduction .
      when vfr you should be able to make runway when you reduce power. I was taught to always make power off landings. That way when you have an engine failure it’s a normal landing , just off runway.

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