What happened
On 15 February 2013, a Thruster T600N 450, registration G-KYLE, was performing a private flight returning to Newtownards. After approximately 75 minutes of flight time, the aircraft was climbing through 1,600 ft toward a target altitude of 2,000 ft when the propeller suddenly detached from the engine.
Following the engine failure, the pilot initiated standard emergency procedures and circled the area to select a suitable landing site. The pilot chose a field near Killinchy, Co Down, for a forced landing. While the touchdown itself was gentle, the aircraft overran the chosen field, striking a hedge at the far boundary. This impact brought down a power cable before the aircraft finally came to a stop in an adjacent field. The aircraft sustained damage to the fuselage and the right wing. The pilot sustained a minor injury to his knee, and the passenger evacuated the aircraft immediately due to the risk of fire. The occupants alerted nearby residents to the situation.
The investigation
The AAIB investigation focused on the mechanical failure of the propeller assembly. Examination of the propeller flange mounting screws revealed that they had failed due to fatigue. The investigation noted that this failure mechanism appeared consistent with previous incidents involving the same engine and propeller combination.
Records showed that G-KYLE had been in compliance with existing service bulletins, having had the mounting screws replaced in November 2009. Since that replacement, the aircraft had flown 253 hours. The investigation compared this event to three prior propeller detachments involving similar aircraft configurations, all of which occurred before the components reached 500 operating hours.
Findings
- The propeller detached from the engine during a climb.
- The flange mounting screws failed due to fatigue.
- The failure pattern was highly similar to previous investigations involving the same engine and propeller type.