Narrative
The pilot reported that shortly after takeoff, the engine began losing power at an altitude of approximately 150 feet above ground level. The sound from the engine was reminiscent of a clogged fuel filter. In response, the pilot jettisoned the load and conducted an emergency landing in a nearby field. During the landing roll, the aircraft struck a fence and subsequently nosed over.
Investigation
An examination of the engine by the operator did not reveal any mechanical failure. The operator noted that the pilot had leaned the mixture during the takeoff phase. After the engine lost power, the pilot attempted to restart but was unable to do so in time to keep the aircraft airborne.
Probable Cause
The probable cause, as stated by the operator, was that the pilot had leaned the mixture during takeoff, and after the engine lost power, he could not restart the engine in time to keep the aircraft airborne.