Incident Overview
A flight instructor conducted a takeoff attempt at an airport with an elevation of 5,042 feet and a density altitude of 7,600 feet. The first takeoff attempt was aborted because the engine RPM was insufficient for takeoff. On the subsequent attempt, the airplane became airborne and flew in ground effect, but the engine RPM remained insufficient to sustain flight.
Pilot Actions
The flight instructor took control of the airplane and banked to avoid powerlines. The airplane subsequently descended into an open field. The instructor reported that he did not lean the mixture for takeoff, believing that the carburetor had an auto-lean feature. However, the engine installed was a fuel-injected IO-360, which does not have an auto-lean function.
Post-Accident Findings
A post-accident engine run revealed that the engine was capable of normal operation when the fuel mixture was properly set. The engine power loss during the incident was attributed to the lean mixture not being adjusted for the high-density altitude conditions.