What happened
On the morning of 18 March 2024, a pilot prepared to fly a Yakovlev Yak 55, registration ZU-DSH, from Karoo Gateway Aerodrome (FABW) in the Western Cape to Bloemfontein. Following a routine pre-flight inspection and refueling, the pilot attempted to start the engine using a manual hand-cranking method on the propeller. This method was employed because the aircraft's engine starter system was non-functional.
During this process, the pilot requested assistance from two individuals to hold the aircraft in place to prevent movement. However, the pilot was not inside the cockpit at the moment of ignition, and the aircraft's parking brakes were not applied, nor were wheel chocks in place. Once the engine fired, the Yak 55 rolled forward unexpectedly, striking a fuel bay perimeter fence. The collision resulted in substantial damage to the propeller, the right main landing gear, and the right wing tip, as well as damage to the fence. There were 0 fatalities and 0 injuries.
The investigation
SACAA AIID examined the circumstances surrounding the engine start and the mechanical state of the aircraft. The investigation confirmed that the pilot held a valid Commercial Pilot Licence and that the aircraft's maintenance and registration documentation were up to date. Investigators focused on the specific mechanics of the engine start, noting that the pilot was utilizing a manual technique to bypass a known defect in the electrical starting system.
Findings
- The aircraft was operated using an unapproved engine start procedure that was neither found in the Pilot’s Operating Handbook nor authorized by regulatory authorities.
- The engine start was attempted without the cockpit being occupied, leaving the aircraft without an operator to manage movement.
- Essential safety measures to prevent uncontrolled rolling were absent, specifically the failure to engage the parking brakes or utilize wheel chocks.
- The pilot's reliance on an alternative hand-cranking method was necessitated by an existing, unrepaired defect in the engine's starter system.