What happened
On 7 August 2015, a Pegasus Quik, registration G-CBZT, was conducting a training flight at Eshott Airfield in Northumberland. During the final circuit of a practice session, the instructor took control of the aircraft to demonstrate a powered approach. The aircraft touched down at a relatively high speed.
Following the touchdown, the student, who was positioned in the front seat, attempted to apply the brakes. However, the aircraft failed to decelerate as expected. The instructor, attempting to manage the situation, tried to terminate engine operation by switching off the magnetos. Despite this action, the engine continued to run. As the aircraft approached the end of the runway and a boundary fence, the student attempted to steer the aircraft to the left to avoid the obstacle. Due to the excessive speed, the aircraft rolled onto its right side.
There were no injuries to the two occupants during the incident.
The investigation
The investigation focused on why the engine remained operational despite the instructor's attempts to use the magneto switches to shut it down. The aircraft was subsequently returned to the manufacturer for repairs. During this process, investigators identified a mechanical fault within the ignition system. It was determined that a grounding wire connected to the ignition unit had suffered an internal break. This defect caused one magneto to remain permanently live, preventing the engine from being stopped via the cockpit controls.