Amateur-built S-18 THORP N575DG accident near Porterville, California

Probable cause

The pilot’s failure to maintain directional control during the takeoff roll.

NTSB analysis

The pilot of the tailwheel-equipped airplane reported that, during takeoff, he advanced the throttle to full power, maintained the runway centerline, and began to raise the tail. He added that, about 60 mph, the airplane suddenly turned left. He applied full right rudder to no avail. Subsequently, the airplane continued to veer left, exited the runway into plowed dirt, and nosed over.

The airplane sustained substantial damage to the fuselage and vertical stabilizer.

The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

The automated weather observation system at the airport reported that, about the time of the accident, the wind was variable at 3 knots. The pilot was departing from runway 30.

Text from the NTSB. Open the NTSB docket for GAA18CA523 for the full record.