What happened
On November 13, 2014, an Eurofly Flash microlight, identified as 26-AFT, was conducting a training flight at the Étoile-sur-Rhône airfield. After completing an initial circuit, the student pilot performed a touch-and-go maneuver on the unpaved runway. During the subsequent initial climb, at an altitude of approximately 300 feet and a speed of 100 km/h, the upper attachment of the right wing's forward strut failed. This structural failure caused the aircraft to pitch down into a spin. The instructor took control and attempted to use the rudder to counteract the rotation, but the aircraft maintained a steep nose-down attitude and collided with the ground. The impact resulted in two slight injuries and the destruction of the aircraft.
The investigation
The BEA examined the wreckage of the failed attachment and performed fractographic analysis on the broken bolt. The investigation confirmed that there was no evidence of prior damage to the component. To determine if the failure was isolated, investigators examined the remaining three struts on the aircraft. This examination revealed bending deformations and thread-root cracking on the rear right and forward left struts. Furthermore, investigators compared these findings with components from a similar Eurofly Flash involved in an accident in April 2015, which also showed pre-existing fatigue cracks in the threaded sections of two out of four bolts.
Findings
- The primary cause of the accident was the fatigue failure of the upper attachment for the forward right wing strut.
- Comparative analysis of the aircraft's other struts and components from a previous accident of the same type revealed a pattern of service-induced damage, including fatigue cracking in five out of eight examined bolts.
- Pre-flight inspections by both the mechanic and the pilots had failed to detect any visible anomalies on the strut attachments.