What happened
On 8 July 2021, a modified Druine D.31 Turbulent, registration G-AREZ, was performing a private flight from Easterton Airfield. Following a routine takeoff, the aircraft reached approximately 150 ft agl when the engine suddenly lost all power. To avoid trees and undulating terrain ahead, the pilot initiated a left-hand turn. During this maneuver, the aircraft entered a stall at roughly 50 ft agle, characterized by a significant wing drop.
The aircraft struck the ground in a nose-down, wings-level attitude. The impact caused the engine to separate from the airframe and the fuselage to break in two just forward of the cockpit. The pilot sustained serious injuries and was briefly unconscious following the impact. Due to the use of a flying helmet, the pilot was able to regain consciousness, unbuckle from his harness, and move away from the wreckage to call for help.
The investigation
An inspection by the Light Aircraft Association examined the engine and fuel systems, finding them to be in normal working order. Investigators also ruled out carburetor icing as a cause. The examination focused on the ignition system, specifically the Leburg controllers which rely on sensors detecting magnets on the propeller spinner backplate.
Investigators discovered that the spinner backplate was damaged and one magnet had become detached, likely due to insufficient adhesive. Furthermore, the wiring harness for the two controllers was incorrectly configured. Instead of an alternating north-south sequence required for proper operation, the wiring was set up so that both controllers responded to the same magnetic pole. This configuration meant that the loss of a single magnet would immediately interrupt the ignition sequence and stop the engine.
Findings
- The engine experienced a sudden loss of power during the climb.
- The loss of a magnet from the propeller spinner backplate, combined with incorrect ignition system wiring, caused the engine to stop.
- The pilot's attempt to maneuver around obstacles led to an aerodynamic stall at low altitude.