Covering form of preliminary or final report

Date of event:	2022.08.09
Incident number:	CZ-22-0857
Report:	Final report
Place of event:	1,3 km NE Staré Sedlo
Registration mark:	Accident
Weight category MTOM::	<2250 kg
Type of operation:	Recreational and sport aviation
Plane / SFM:	Gliders
Type of plane / SFM:	Rolladen-Schneider LS4-A a LS8-18
Health effects of event:	Without injury
PDF document:

Description:

Synopsis

On 9 August 2022, the AAII received an accident notification in relation to the mid-air collision of the LS4-A and LS8-18 gliders. The pilots of both gliders were participants of the 12th FAI Junior World Gliding Championship (JWGC 2022) held by Aeroklub Tábor, z.s. at the Tábor airfield. During the flight, while performing a competition task, the LS8-18 pilot was circling in the upstream while the LS4-A pilot wanted to join the gliders he saw circling in the upstream. As the LS4-A pilot started the turn to fly into the upstream, the LS4-A and LS8-18 gliders collided. Given the impact intensity, the fragmentation of the glider cockpit canopy, rotation and rolling into steep descent, the LS4-A pilot was sure that the glider had been seriously damaged and that is why he departed the glider using an emergency parachute. He landed on a parachute about 1.7 km away from the place of glider’s fall. He was uninjured and sought help. The LS4-A glider was damaged heavily due to its collision and fall in the forest. After an impact, the LS8-18 pilot tested the controllability of his glider. Having found out that he can continue in the descending flight, he was looking for a place to land in the terrain. He landed on the field approx. 7 km NE from the place of collision. He did not suffer any injuries. The LS8-18 was slightly damaged due to the collision.

Findings

• The pilots had valid qualification and were medically fit for performing the given flight.
• The pilots had experience with and habits of conducting competitive flights with gliders.
• The gliders were airworthy.
• The gliders’ equipment complied with the technical requirements of the competition.
• During visual inspection of the gliders, no evidence of a defect or failure of controls that could have contributed to the occurrence of an air accident was detected.
• The LS4-A and LS8-18 gliders collided when the LS4-A glider pilot was joining the gliders circling in right-hand turns in the upstream at almost the same level.
• The LS4-A glider pilot wanted to join the gap between two circling gliders and was aware of the LS8-18 glider, but failed to recognise that due to his position in relation to the LS8-18 glider and the turn at almost the same level he would not be able to keep a safe distance.
• The LS8-18 glider pilot was aware of the presence of another glider approaching outside the turn, but could not predict the imminent collision as his view of the LS4-A glider in immediate vicinity was shielded.
• The pilots did not detect an imminent collision in time in spite of the fact that they had functional FLARMs on board. It was probably due to the presence of other gliders nearby.
• The extent of damage to both gliders and the explanation of both pilots correspond to the impact of the wing of the LS8-18 glider from above and from behind into the fuselage of the LS4-A glider.
• After the collision, the LS4-A glider pilot made an emergency exit using an emergency parachute and landed near the place of glider’s fall while the LS8-18 glider pilot landed at a suitable place and informed the competition organiser of the situation.

Air Accident Cause

The cause of the air accident was an error of the LS4-A glider pilot when evaluating the movement of gliders in the upstream and incorrect joining of the circle, which resulted in non-compliance with the safe distance and lack of time to avoid the collision.


Attached final report in PDF file is in original Czech language.