Incident Overview
A pilot, pilot-rated passengers, and a mechanic ground witness reported that the aircraft required the entire length of the runway to become airborne. After liftoff, the aircraft would not climb and, while flying in ground effect, collided with a tree approximately one mile from the end of the runway.
Environmental Conditions
The density altitude at the time was computed to be just over 7,000 feet.
Witness Observations
The mechanic witness stated that during the takeoff ground roll, the engine sounded as if the carburetor heat was engaged.
Post-Accident Examination
A detailed examination of the engine revealed that the exhaust valve on the number two cylinder was stuck in the open position. An engine overhaul facility reported that the valve was stuck due to a considerable amount of carbon in the valve guide.