What happened
On September 20, 2015, an SG-92 Turbo Finist was engaged in skydiving operations at Ostrów Wielkopolski-Michałków airport (EPOM). Following two successful flights, the pilot attempted to start the engine for a third flight but failed due to rising inter-turbine temperature (ITT). After a dry start and a subsequent successful start, the pilot completed two additional flights without incident.
During the takeoff roll for a subsequent flight, the pilot detected an intense smell of JET A1 fuel and an abnormal engine noise. The pilot aborted the takeoff shortly after rotation, at an altitude of less and than one meter, and brought the aircraft to a stop midway down the runway. Although the aircraft taxied back to the apron, the unusual noise and fuel odor persisted. The pilot shut off the fuel supply and all generators, and the crew safely egressed the aircraft.
Upon inspection, the pilot found no visible fuel leaks or engine defects. During a subsequent dry start performed near a hangar, the pilot noted sounds resembling mechanical friction. Following the incident, the continuing airworthiness management organization ordered a special engine inspection.
The investigation
The investigation focused on identifying the source of the fuel odor and the abnormal engine sounds. A borescope inspection of the engine interior was conducted, which revealed no internal irregularities. Additionally, the generator, fuel pump filters, and oil filters were inspected and found to be in good condition. The inspection did reveal excessive wear on the spark plugs, which were subsequently replaced. A subsequent engine test and a technical flight were performed, both of which showed no further issues, allowing the aircraft to return to service.
Findings
- The investigation determined that the unintentional activation of the aircraft's cabin heating was the most likely cause of the fuel odor and the abnormal engine sounds.
- Excessive wear on the spark plugs was identified as the likely cause of the initial failed engine start earlier in the day.