What happened
On 29 March 2019, a flight instructor and a student pilot were conducting asymmetric engine training exercises at Syferfontein Aerodrome. The flight, operating a Piper PA 30 with registration ZS-ICB, involved simulating engine failures to practice single-engine procedures. After a successful landing following a simulated failure, the student pilot attempted a touch-and-go maneuver by applying full power for a subsequent takeoff.
As the aircraft reached approximately 80 knots and began rotation, it experienced a sudden, sharp pull to the right. The instructor took control to stabilize the aircraft and attempted to feather the right engine, but the engine failed to respond as expected. The aircraft lost altitude at a very low height, causing the right wing to strike the ground. The impact triggered a ground loop, and the aircraft eventually came to rest 120 meters beyond the runway threshold. Both the instructor and the student pilot sustained minor injuries, but the aircraft was destroyed.
The investigation
SACAA AIID investigators examined the wreckage and the aircraft's maintenance history. The investigation focused on why the right engine failed to develop power during the critical climb phase. Physical examination of the engine components revealed that the throttle control cable end fitting on the right-side engine was missing from the wreckage.
Further analysis determined that the fitting found in the wreckage was not the original equipment specified by the manufacturer. The investigation traced the installation of this part to a maintenance session performed by an Aircraft Maintenance Organisation (AMO) that has since ceased operations. It was discovered that the fitting lacked a necessary ball joint retainer, which is a requirement for this aircraft model.
Findings
- The primary cause of the accident was the separation of an incorrect throttle control cable end fitting on the right engine when full power was applied.
- The failure of this component prevented the right engine from developing the power necessary to maintain flight during the climb.
- The maintenance organization used an unapproved part that did not comply with the manufacturer's Service Bulletin (SB 515).
- The installation of the incorrect fitting violated Civil Aviation Regulation Part 43.02.22.
- Weather conditions at the time of the accident were clear and did not contribute to the event.