C4/2007L Microlight emergency landing in Petsmo on 24 June 2007

An accident occurred at 11:20 Finnish time on Saturday, 24 June 2007 at Petsmo. A privately owned BMW Lazer Ipsos weight-shift controlled microlight aircraft (a.k.a. ultralight or ML), registration F-JZUH, was badly damaged in a forced landing. The aircraft was manufactured by Metallerie Jacques Chapelet. On 26 June 2007, Accident Investigation Board Finland (AIB) appointed an investigation commission C4/2007L for this incident. Investigator Ismo Aaltonen was named Investigator-in-Charge with Investigator Toni Mäkelä as member of the commission.

The microlight had departed Pori airport (EFPO) at 09:24 with the intention to fly to Kokkola (EFKK). The route took the ML to the north, along the coast of the sea. The altitude varied between 200–400 m. The engine suddenly stopped west of Petsmo village (approximately 20 km north of Vaasa airport). The pilot decided to make an emergency landing in the only possible open space nearby, which was a marsh. Judging by the markings on the ground, touchdown was normal. However, the surface was so soft that the microlight rolled twice and was badly damaged. The pilot was seriously injured but the passenger escaped without injuries.

Subsequent test and research revealed that the generator’s drive belt snapped during the flight. Ignition, fuel injection and the fuel pump all require electricity to function. After the generator belt snapped, engine systems got their electricity from the battery. Approximately one hour after the generator failure the battery was drained enough to stop the engine.

The pilot was not sufficiently informed of the microlight’s electrical system. He was not aware of the significance of the generator warning light, nor of the battery voltage indicator. It is possible that he did not detect that the telltale light was on because of the bright sunshine. In this case, battery voltage indication is the only sign of generator failure.

The investigation commission issued no recommendations because pilots themselves are mainly responsible for weight-shift controlled microlight operations. However, the investigation commission urges weight-shift controlled microlight instructors and pilots to pay attention to the following: as regards flight safety, it is essential that the pilot be sufficiently familiarized/trained on the aircraft’s systems and emergency procedures at the very onset of flight training.

C4/2007L Report (pdf, 0.24 Mt)