Cessna 150H N7250S accident near Mansfield, Massachusetts

Probable cause

The pilots’ failure to apply carburetor heat during takeoff, which resulted in a partial loss of engine power due to the formation of carburetor ice.

NTSB analysis

The flight instructor stated that during takeoff, when the airplane reached 250 feet above ground level, it "stopped climbing." The flight instructor assumed control of the airplane from the student and verified the position of the engine controls; however, despite adjusting airspeeds between best rate and best angle of climb, the airplane continued to descend until it settled into trees off the departure end of the runway, resulting in substantial damage to the empennage and tail sections. The occupants egressed without injury. After the accident, the airplane was removed from the trees by local authorities and placed inverted on the ground. As a result, all residual fuel drained from the airplane, and no fuel was available for testing. Examination of the airframe revealed no preimpact mechanical anomalies that would have precluded normal operation. The engine was removed from the airframe and placed in a test cell where it started immediately, accelerated smoothly, and ran continuously at rated power. Atmospheric conditions at the time of the accident were conducive to serious icing at any power setting, and the flight instructor stated that he ensured that the carburetor heat control was in its cold position during the takeoff. Therefore, it is likely that the loss of engine power was related to the accumulation of carburetor ice during takeoff.

Text from the NTSB. Open the NTSB docket for ERA13LA034 for the full record.