A small single-engine aircraft came to rest upside down in a field off the runway at Auburn Airport (AUN) Tuesday.

The two-seat Bellanca Decathlon landed on its wheels before skidding off the runway and into the grass where it flipped over, Auburn Fire Assistant Chief Tony D’Ambrogi told Wingman. Both occupants, a student and an instructor, exited the aircraft on their own and no extraction was needed, he said.

“The aircraft owners expressed their gratitude to the first responders and airport manager for their quick response and management of the incident,” D’Ambrogi said.

Airport manager Tyghe Richardson was at the scene and coordinated with authorities to remove the aircraft from the area and investigate the cause, according to D’Ambrogi.

“It is unclear and undetermined at this time if this incident was a mechanical failure or human error,” he said.

Weather data for the airport at the time of the incident shows calm winds around 5kts with visibility of 10 miles or more. The temperature was around 78F (26C) to 82F (28C). The field elevation is 1,539 feet above sea level. 

Aircraft such as the Decathlon use a tailwheel landing gear configuration where the center of gravity is behind the main landing gear. The FAA Airplane Flying Handbook describes tailwheel aircraft as “inherently unstable on the ground,” as the aircraft have a tendency to pivot around the center of gravity during landing or takeoff. 

Pilots are required to have a specific endorsement from the FAA to fly tailwheel aircraft and incidents that pilots refer to as a “ground loop” are known to occur during the takeoff or landing phases of flight. A ground loop can be caused by several factors including winds, pilot error, and mechanical problems. 

The specific cause of Tuesday’s incident is under investigation, authorities said.