CEN22LA002 · Beech B23

The airplane was on the first flight following an annual inspection in which the carburetor had been changed along with other maintenance. The pilot reported that, during the preflight inspection, both fuel tanks were full and everything was normal except for a non-working rotating beacon. She reported that the engine started normally, and the engine checks were normal except that the engine rpms were slightly lower than before the carburetor replacement. The pilot performed one takeoff and landing without difficulty. On the ensuing takeoff, when the airplane reached the departure threshold, the engine power reduced to idle. The pilot made a forced landing in a field and the airplane sustained substantial damage to the right wing. The pilot reported that she did not use carburetor heat during the takeoff or landing because the temperature was above 75° F and the humidity was low; however, the temperature and dewpoint recorded at the accident airport were favorable for serious carburetor icing at glide power settings. Postaccident examination revealed that the fuel selector valve was not in a detent and was positioned between the left and off positions. The pilot stated she did not move the fuel selector valve during or after the flight. Investigators were unable to determine when the fuel selector valve was moved to this position. The postaccident examination also revealed that a cotter pin was not installed on the nut and bolt that secured the throttle cable to the carburetor throttle arm; however, the nut and bolt were still in their proper position and finger tight and did not prevent normal operation of the throttle. The right fuel tank was found full of fuel and the left tank was empty after the accident. The fuel tanks were not compromised and no leaks were noted. The reason the left fuel tank was empty when the pilot had verified it was full before the flight could not be determined. No other mechanical discrepancies were found that would have prevented normal operation. Based on the available information, the loss of engine power could have been the result of improper fuel selector positioning, which reduced fuel flow and starved the engine for fuel, fuel starvation due to inadequate fuel supply from the left fuel tank, or the pilot’s failure to use carburetor heat during the flight when conditions were conducive for serious carburetor icing. The reason for the loss of engine power could not be determined due to the multiple possibilities discovered during postaccident examination.

Verbatim NTSB analysis and probable cause from the NTSB dataset