Beech B19 N9721Q accident near Scott City, Kansas

Probable cause

A partial loss of engine power as a result of carburetor icing that formed while the engine was operating at a low power setting for an extended period before departure.

NTSB analysis

The pilot stated that after he started the engine, he let it idle about 600 rpm for a “few minutes,” and began to taxi to the runway for departure. He waited for another airplane to perform a back-taxi and depart, then he back-taxied and completed an engine run-up before realizing he left something behind. He then taxied back to the fixed base operator (FBO), collected his items, and again taxied to the runway for departure. He did not complete another engine run-up before takeoff.

During the takeoff roll, he noticed the engine rpm increased and did not note any anomalies. During the initial climb, the engine rpm maintained about 2,200 rpm with full throttle set. He stated that he was able to climb about 500 ft above ground level (agl) and attempted a return to the airport. He said that when he was abeam the runway, he thought he was “losing altitude and power,” and made a shallow left turn towards the runway. Unable to maintain altitude during the turn, the pilot landed on a dirt road. During touchdown, the airplane bounced, exited the roadway, impacted a ditch, and slid into a cornfield, which resulted in substantial damage to the fuselage.

During a postaccident examination, no preimpact mechanical malfunctions or failures were discovered that would have precluded normal operation.

When the temperature and dewpoint at the time of the accident were plotted on a carburetor icing probability chart, it was revealed that the airplane was operating in an environment conducive for serious carburetor icing at a glide power setting. The pilot stated that he checked the carburetor heat before departure. After the carburetor heat check, it is likely that ice began to form in the carburetor’s venturi during the extended ground operation before departure, which, in turn, limited the engine rpm at 2,200.

Text from the NTSB. Open the NTSB docket for CEN23LA264 for the full record.