What happened
On July 24, 2005, at Jämi airfield, a towing operation involving a Rallye Commodore (OH-SDV) and a SZD-50-3 Puchacz glider resulted in a fatal accident. The flight, intended as a celebratory "bachelor party" flight for passengers, commenced from runway 27. After an initial 90-degree left turn, the glider drifted into a position that forced the tow plane's tail upward.
The pilot of the Rallye Commodore attempted to release the tow line, but the release failed on the first attempt. By the time the line was successfully disconnected, the aircraft was at too low an altitude to recover. The tow plane plunged into a pine forest at an angle of approximately 40 degrees, causing the wings to break. The pilot sustained serious injuries.
Following the separation, the glider pilot managed to steer the aircraft toward the airfield and landed on the grass near the middle of runway 33, with the tow line still attached to the nose hook.
The investigation
The investigation examined the weather conditions, the flight preparation, and the mechanical state of the aircraft. Investigators found that the pilots had not sufficiently checked the weather via available internet services at the airfield. The investigation also focused on the impact of the recent rain on the aircraft's performance and visibility.
Findings
- The primary cause of the accident was the decision by the pilots to proceed with the flight in rapidly changing and poor weather conditions.
- The glider's position relative to the tow plane caused the tow plane's tail to pitch up.
- Heavy rain and high humidity caused condensation on the inside of the glider's canopy, significantly reducing the glider pilot's forward visibility.
- The approaching rain shower was not detected during pre-flight preparations due to the terrain obscuring the view.
- The rain had weakened the climbing performance of the tow combination.
- The low altitude at the time of the tow line release left insufficient margin for the tow plane to recover from its descent.
Safety action
- The commission recommends that the Finnish Civil Aviation Authority update regulation OPS M8-8 to establish minimum weather requirements of 8 km visibility and a 450 m cloud base for glider demonstration flights involving passengers.