On August 2, 1990, a Boeing A75N1 (registration N25400) operated by Lewkowicz, John D. was involved in an aviation accident near Oshkosh, WI. Investigators recorded the probable cause as: THE PILOT-IN-COMMAND'S FAILURE TO MAINTAIN AIRSPEED SUFFICIENT TO AVOID A STALL/SPIN AT AN ALTITUDE INSUFFICIENT TO EFFECT A FULL RECOVERY. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During an aerobatic demonstration at the EAA convention, an aircraft performing a slow roll departed controlled flight at the inverted position, entered an uncommanded snap roll, and descended into terrain.
Maneuver
The aircraft was engaged in performing aerobatic maneuvers in connection with the Experimental Aircraft Association's convention. During the demonstration, the aircraft entered a slow roll to the left.
Loss of Control
At approximately the inverted position of the slow roll, the aircraft departed controlled flight. It then entered an uncommanded snap roll—characterized as a stall/spin—to the left. The aircraft completed three-quarters of a full roll rotation before stopping in a knife-edge flight attitude.
Descent and Impact
Stabilized momentarily in knife-edge flight, the aircraft descended approximately 200 to 300 feet into the terrain.