What happened
On March 30, 2002, an Aviasusc Mistral micro light aeroplane, registration PH-2S4, crashed in a ploughed field near Mussel, Netherlands. The aircraft, which was owned by the pilot, had not flown since August 1, 2001, and had recently undergone superficial cleaning. Following a short solo flight and a brief stop at Stadskanaal airfield to pick up a passenger, the aircraft departed again. During the flight, witnesses reported hearing unusual noises, described by some as engine trouble and by others as a loud flapping sound. The aircraft subsequently entered a left spin and plummeted into the ground at an angle of more than 45 degrees. The crash resulted in two fatalities and the total destruction of the aircraft.
The investigation
Because micro light aeroplanes are not certified under international airworthiness standards, the investigation by the Dutch Safety Board was limited to establishing facts and a summary analysis. Technical examination of the wreckage revealed significant structural damage. The wing covering appeared aged, particularly at the adhesive joints, and a portion of the covering on the left upper wing had torn away. Furthermore, the spar of the left lower wing had buckled near its attachment to the fuselage and had completely broken further toward the wingtip. The left diagonal wing strut was also found to be sharply folded.
Engine analysis indicated that the powerplant likely functioned normally. An autopsy of the pilot found no medical conditions that would have impaired his ability to fly. The investigation also noted that while the aircraft operated under a permit to fly, there was no specific formal regulation for MLAs in the Netherlands at the time, though advisory notices had been issued regarding the Mistral type.
Findings
- The left lower wing failed due to overload.
- This overload may have been caused by aerodynamic flutter, which might have been triggered by the tearing of the wing covering, or vice versa.
- The aircraft entered a left spin as a direct result of the wing covering tearing or the disintegration of the left lower wing.
- There was no evidence of engine failure contributing to the accident.
- The aircraft's wing and tail surfaces were covered in plastic film; manufacturer instructions require a complete overhaul and replacement of this covering every 2,000 flight hours or five years, but records of such a revision for this aircraft were not found in its logbook.