Consolidated Aeronautics Inc. LAKE LA-4-200 N80033 accident near Lakeport, California

Probable cause

The pilot's decision to continue the takeoff with reduced engine power, which resulted in a collision with terrain during the takeoff initial climb. Contributing to the accident was the partial loss of engine power for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.

NTSB analysis

Two witnesses watched the airplane take off and observed that the engine was not developing full power. The witnesses reported that the airplane barely cleared the trees, which were located about 950 feet beyond the end of the runway, and a few seconds later, the airplane banked right and nosed down out of sight. When the witnesses arrived at the crash site, the airplane’s engine was still running, and one of the witnesses shut off the fuel to turn off the engine. The pilot reported that the engine lost partial power during the initial climb after takeoff and that there was not enough runway left to put the airplane back down and stop. However, the witness observations indicate that the airplane was likely not developing full power during the takeoff ground roll and the pilot should have been able to abort the takeoff if he had recognized that the engine was laboring earlier in the takeoff roll. Within the 4 months preceding the accident, the airplane had undergone maintenance because the engine was running rough. The maintenance included cleaning of the fuel injectors and fuel screens, overhaul of the fuel servo and the fuel flow divider, and installation of new fuel injector lines. The pilot conducted a test flight of the airplane earlier on the day of the accident during which the engine performed normally. Examination of the airframe and engine did not reveal the reason for the partial loss of engine power.

Text from the NTSB. Open the NTSB docket for WPR11FA424 for the full record.