What aircraft was involved and where did it happen?

The accident on 2002-08-11 involved a TRI KIS, registration G-BXJI, at Cumbernauld Airfield, Glasgow, GB.

What was the probable cause of the accident?

The accident was caused by a heavy bounce during landing and a subsequent wing stall during a go-around maneuver, which led to the aircraft's inversion.

Tri-R Kis inversion at Cumbernauld Airfield

A private flight in a Tri-R Kis ended in an inverted accident at Cumbernauld Airfield after a heavy bounce during landing led to a wing stall and subsequent rollover.

What happened

On 11 August 2002, a Tri-R Kis, registration G-BXJI, was performing a private flight at Cumbernauld Airfield. During the landing sequence on Runway 08, the aircraft experienced a heavy bounce. In an attempt to recover, the pilot initiated a go-around and applied full power. However, the high angle of attack during the early phase of the climb caused the right wing to stall and drop, making contact with the runway surface and pulling the aircraft to the right.

As the aircraft moved onto the adjacent long grass, the resistance caused the plane to pitch forward and invert. The impact resulted in the aircraft coming to rest upside down. The accident caused significant damage, including the separation of the right wing root, the loss of the main landing gear, and a shattered propeller that caused engine shock loading. There were no fatalities and no injuries to the two occupants, though they were initially trapped upside down because the weight of the inverted aircraft prevented the gull-wing doors from opening.

The investigation

The investigation established that the pilot used a handheld fire extinguisher to break the windscreen to facilitate an escape, which inadvertently filled the cockpit with extinguishing agent. The occupants were only able to exit through the doors after ground personnel arrived to right the aircraft.

Investigators noted that while the aircraft was operating under a Permit to Fly, the design of the exits presented a significant risk. Under the JAR VLA guidelines used for the type's approval, aircraft should be designed to allow rapid escape in most crash attitudes, excluding turnover. However, the investigation found that the inability to open the doors in an inverted position would have made a fire extremely dangerous for the crew.

Findings

The pilot flared the aircraft too high during the landing approach, leading to the initial heavy bounce.
A high angle of attack during the go-around maneuver resulted in a right wing stall.
The aircraft's gull-wing doors became inoperable due to the weight of the aircraft while inverted.
The presence of a tool to break cockpit transparencies was noted as a potential life-saving factor, despite the accidental discharge of the extinguisher during the attempt.