What happened
On 12 March 2005, an Aero Trike Cobra, registration ZU-CNE, was involved in an incident at a private aerodrome in Rietfontein, Muldersdrift. The pilot, who also owned the aircraft, had recently completed an engine overhaul involving the installation of new pistons and sleeves. After warming up the engine, the pilot taxied to the runway threshold for a planned circuit and full-stop landing.
During the takeoff roll, the pilot performed standard pre-takeoff and magneto checks, which initially showed no issues. Shortly after departing in a southerly direction and initiating a left turn, the engine failed at an altitude of approximately 200 ft AGL. The pilot attempted to turn the aircraft back toward the runway, completing a 180-degree turn before performing a forced landing. The aircraft approached the runway at a slight angle, crossing the runway surface and onto uneven terrain, where it tipped onto its right side. There were no injuries to the pilot, though the aircraft sustained minor damage to the profile tube and the right-hand main wheel spat.
The investigation
Investigators examined the Rotax 582 two-stroke engine at an approved overhaul facility. The inspection revealed that the front piston had seized during flight. Records indicated that the aircraft had flown only 9.8 hours since its last annual inspection in December 2004. The investigation focused on the mechanical state of the engine following its recent overhaul.
Findings
- The engine failure was caused by a cold seizure of the front piston.
- The seizure occurred because the engine had not been run in for a sufficient duration following the installation of new components.
Safety action
- Following the investigation, the Rotax engine overhaul facility implemented an extended run-in period for engines following an overhaul to mitigate the risk of similar piston seizures.