Grumman G164 N8712H accident near Madera, California

Probable cause

The pilot’s loss of directional control during takeoff with a quartering tailwind, which resulted in a runway excursion and separation of the right landing gear.

NTSB analysis

The commercial pilot reported that the tailwheel-equipped airplane veered to the left during takeoff on the fourth flight of the day. He applied full right brake and rudder to correct; however, the airplane veered off the runway and the right main landing gear separated from the airframe. The pilot stated that the wind conditions at the time of the accident included a 7 to 10 mph left quartering tailwind with occasional gusts to 12 to 14 mph.

A postaccident examination of the right brake revealed no evidence of preimpact mechanical malfunctions or failures that would have precluded normal operation. The airplane incorporated a free-swivel, non-lockable tailwheel assembly; directional control on the ground was accomplished by application of differential braking until adequate airspeed was attained for the rudder to become effective. It is likely that, due to the quartering tailwind, the airplane had not yet attained an adequate airspeed for rudder effectiveness and that the pilot's braking action was insufficient to overcome the left yaw.

Text from the NTSB. Open the NTSB docket for WPR17LA100 for the full record.