Northwing Design APACHE SPORT N2725T accident near Omro, Wisconsin

Probable cause

The pilot’s failure to maintain adequate airspeed to compensate for a newly installed wing, which resulted in the aircraft stalling and the subsequent loss of control.

NTSB analysis

The student pilot had installed a smaller, higher performance wing on the weight-shift control trike just before the accident flight. A witness reported seeing the trike in a descending spiral about 1 hour after it had taken off. The trike impacted terrain in a field along the final approach course for the airstrip at the departure airport.

The installation of the smaller wing increased the stall speed of the trike. It is likely that the student did not account for this increase as he slowed the trike in preparation to land, which resulted in an inadvertent stall from which he did not recover. There were no records located during the investigation to determine the pilot's experience in this or any other aircraft. A postaccident examination of the airframe, wing, and engine did not reveal any preimpact failure or malfunction.

Toxicology testing revealed that the pilot had recently used tramadol and amphetamine, but there was insufficient evidence to determine whether the drugs contributed to the cause of the accident.

Text from the NTSB. Open the NTSB docket for CEN14LA336 for the full record.