What happened
On 17 February 2018, a Cubby Wings Tri-Cubally (registration ZU-EED) was conducting a national pilot’s licence skills test at Middleburg Aerodrome. The flight, which included a student pilot and a flight instructor, was returning from the general flying area when the instructor directed the student to perform a touch-and-go maneuver on runway 14.
As the student pilot applied full throttle to climb following the landing phase, the engine suddenly stopped at an altitude of approximately 20 meters above ground level. The student pilot attempted to execute a forced landing on the remaining runway surface. However, the aircraft struck the ground with a high rate of descent, causing the main landing gear to collapse and the nose gear strut to bend. The aircraft eventually came to rest on the side of the runway. There were no injuries to the two occupants.
The investigation
The investigation examined the mechanical state of the aircraft and the circumstances of the flight. The Cubby Wings Tri-Cubby was found to have a valid authority to fly and a current certificate of release to service, with its last annual inspection completed in January 2018. The aircraft was powered by a Volkswagen 2.1 engine, which utilizes a single ignition source. At the time of the incident, the aircraft had flown only 7.7 hours since its last major inspection.
Findings
- The engine failure was caused by the failure of the ignition lead connecting the distributor to the spark plugs.
- Because the engine relies on a single ignition source, the break in the lead prevented the spark required for combustion, resulting in an immediate engine shutdown.
- The high rate of descent during the landing attempt led to significant damage, including a distorted fuselage, a damaged propeller, and collapsed landing gear.