Incident Sequence
During the takeoff roll, the pilot was aware that the runway had a pronounced dip just before the rotation area. As the aircraft passed through the dip, the pilot felt a shimmy, which he attributed to the nose gear's reaction to the dip. He considered aborting the takeoff but concluded insufficient runway remained to stop safely.
After liftoff, the aircraft began to experience severe vibration, preventing a climb above 100 feet above ground level (AGL). The pilot maneuvered to avoid tall trees in a wooded area ahead but could not maintain safe altitude and airspeed. He allowed the aircraft to stall and mush into the trees.
Background
The pilot stated that his initial checkout in the aircraft make and model included instructions to hold the nose on the ground until reaching 90 knots. An FAA inspector commented that this speed is excessive and will cause the aircraft to wheelbarrow.
Investigation Findings
Post-accident investigation revealed that the aircraft had a nosedown trim setting. Propeller marks were observed on the runway, and all propeller blades were bent rearward approximately 4 inches from the tips.