B3/2005L Aircraft accident in Jämijärvi on 24 July 2005

On Sunday, July 24th 2005 at 13.40 (Finnish time) an aircraft accident occurred near Jämi airfield where OH-SDV of type Rallye Commodore was destroyed. The accident happened during glider towing operation. The pilot of the tow plane was seriously injured in the impact. Accident Investi-gation Board Finland set 26.7.2005 by its decision number B3/2005L an investigation commission. Investigator Tapani Vänttinen was nominated as the investigator-in-charge and investigator Ismo Aaltonen as a member of the commission. For meteorological issues the commission heared meteorologist Tapio Tourula as a specialist.

The tow plane started towing a glider of type Puchacz from Jämi runway 27. After approximately 90° left turn 2-seater glider climbed to a position, where it lifted the tail of the tow plane up. The tow pilot released the tow line, but due to low altitude he could not recover the aircraft and it c-rashed into pine trees. After this the glider pilot turned left towards airfield and landed on runway 33 with tow line hanging on the hook.

It emerged during the investigation that for both pilots checking the weather during flight prepara-tion was insufficient. Also they were not able to see approaching rain shower due low position of the take-off point. Due to rain shower the performance of the tow combination was weakened and high humidity caused thick moisture on canopy surface. Therefore the glider lost the forward visi-bility.

After the tow line release the glider landed on runway 33 without using airbrakes. The cause of the accident was the decision of both pilots to conduct flight in rapidly changing weather condi-tions. The glider drifted to a position where it lifted the tail of tow plane up. Due to low altitude the tow plane crashed into forest.

The investigation commission recommends that Finnish Civil Aviation Authority would add mini-mum weather requirement of 8 km visibility and 450 m cloud base to OPS M8-8 (glider demon-stration flights to passengers).

B3/2005L Report (pdf, 0.77 Mt)