NTSB Identification: WPR10LA429
14 CFR Part 91: General Aviation
Accident occurred Thursday, August 26, 2010 in Willcox, AZ
Probable Cause Approval Date: 01/15/2013
Aircraft: FINNEY THORP T-18, registration: N467JF
Injuries: 2 Fatal.

NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.

The airplane was observed in the traffic pattern, about 500 feet above ground level, when it made a steep left turn to enter the downwind leg. The turn continued as the airplane entered a left descending spiral until it impacted the ground in a nose-low attitude. Postaccident examination of the airframe and engine revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation.

The Pilot Operating Handbook for the airplane indicated that the airplane has an abrupt stall with a tendency to drop a wing, especially if the airplane is in an uncoordinated turn during the stall. There is very little warning preceding the stall. Stall recovery can be quickly affected by releasing back pressure on the stick; however, a secondary stall may occur if the stick is brought back abruptly after recovery without sufficient airspeed. It is likely that during the initial steep turn, the airplane entered an aerodynamic stall from which the pilot was unable to recover at the low altitude.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

The pilot’s failure to maintain sufficient airspeed during a steep turn and at a low altitude in the traffic pattern, which resulted in an aerodynamic stall.

Full narrative available

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