Accident Overview
A training aircraft experienced a loss of engine power during takeoff, resulting in a collision with trees and the ground. The certified flight instructor (CFI) noted that the engine's revolutions per minute (RPM) dropped to 2000 despite full throttle application at an altitude of about 75 feet above ground level (AGL). The CFI attempted to arrest the descent by deploying flaps, but the maneuver was unsuccessful.
Prior Takeoff Attempt
Earlier, one takeoff had been aborted due to poor acceleration. The CFI attributed this to improper throttle technique by the student pilot.
Engine Examination Findings
A post-accident examination of the engine revealed that old-type valve springs were installed. These should have been replaced with part number LW11800, as specified by Avco Lycoming Service Instruction 1240B. That instruction called for the change to improve engine performance. A mechanic had installed new springs, but they were of an incorrect type and featured incorrect color coding.
No Further Details
The report does not specify the aircraft type, registration, engine count, date, operator, location, number of occupants, injuries, or damage items. No determination of probable cause was provided in the source.