Piper J3L-65 N81BF accident near Van Dyne, Wisconsin

Probable cause

The pilot’s inability to maintain airplane control while maneuvering for reasons that could not be determined from the available evidence.

NTSB analysis

The airplane was one of a flight of two that departed for a local sightseeing flight over the lake. The pilot of the other airplane stated that they flew east to the lake and followed the lake shore south at altitudes varying between 1,000 and 1,400 feet. He stated that the accident airplane began a maneuver by pitching up and then climbing. The left wing then dropped and the airplane yawed to the left and descended. During the descent, the airplane became inverted, and the nose of the airplane started to rise and the airplane began to roll to the right. As the airplane rolled, the right wing contacted the water and the airplane crashed into the lake. Rescue divers reported the rear seat passenger was not restrained and the pilot was restrained in his seat. It is possible that there could have been some inadvertent interference with the flight controls by the passenger, but it could not be determined conclusively. A postaccident examination of the airframe and engine did not reveal any failures or malfunctions that would have resulted in the loss of control. An autopsy performed on the pilot determined that multiple cysts that were caused by a parasite were located in the white matter of his brain. It could not be determined if this condition played a role in the accident.

Text from the NTSB. Open the NTSB docket for CEN11FA505 for the full record.