Pilot Flew Aircraft Into Building After Thud and Airspeed Drop (N4840G)

Background

The pilot reported aborting the first takeoff attempt due to reduced acceleration. After aborting, the pilot taxied back via a parallel taxiway and initiated a run-on type takeoff.

Flight and Incident

As the aircraft climbed to an estimated altitude of 50 to 60 feet above the runway, the pilot heard a thud and the airspeed dropped. The pilot stated that the altitude was too low to attempt a turn back to the runway or to fly over a two-story commercial building that was ahead of the aircraft's position. The pilot decided to fly the aircraft into a large glass window of the commercial building.

Post-Accident Findings

A post-accident test run of the engine found that it operated normally. However, it was noted that the carburetor heat valve could not be moved to the full off position. Weight and balance calculations indicated that the aircraft was 174 pounds over the maximum gross weight at the time of takeoff.