What happened
On August 13, 2019, during the 18th HOP 2019 international historical glider competition near Trutnov, Czech Republic, two gliders collided in mid-air. The aircraft involved were a VT 16 Orlik, registration OK-3..'3405, and a VT 116 Orlik II, registration OK-7410.
At approximately 13:39 UTC, the pilot of the OK-7410 was maneuvering to join a thermal updraft where other competitors were circling. The pilot observed two other gliders and intended to fly between them to utilize the rising air. As the OK-7410 approached the area, it was traveling at a higher speed (79 km/h) than the OK-3405, which was already circling in the thermal at 63 km/h.
During the maneuver, the OK-7410 initiated a slight left turn. During this turn, the pilot's attention shifted toward another glider, causing the OK-3405 to momentarily leave the pilot's field of view. In the interval between 13:39:38 and 13:39:44, the two aircraft collided. The impact caused the rear section and tail surfaces of the OK-3405 to break away. Following the structural failure, the OK-3405 entered an uncontrollable descent, striking a cornfield approximately 3 km northwest of Trutnov. The pilot of the OK-3405 sustained fatal injuries.
The pilot of the OK-7410 checked the aircraft's controllability after the impact, found it still flyable, and successfully landed at the Trutnov glider airfield. The pilot of the OK-7410 sustained no injuries.
The investigation
The ÚZPLN investigation examined flight data recorders from both aircraft, analyzed trajectories, and reviewed statements from the pilots and several witnesses on the ground. The investigation reconstructed the collision geometry, determining that the lower part of the OK-3405's fuselage struck the leading edge of the OK-7410's left wing, while the right horizontal stabilizer of the OK-3405 struck the upper surface of the OK-7410's wing.
Findings
- The primary cause of the accident was the improper distribution of the pilots' attention during VFR flight.
- The pilot of the OK-7410 lost visual contact with the OK-3405 while focusing on another aircraft during a turn.
- It is highly probable that the pilot of the OK-3405 was momentarily blinded by the sun, which likely prevented the timely detection of the approaching OK-7410.
- The structural integrity of the OK-3405 was destroyed by the impact, making an emergency bailout impossible due to the rapid rotation and descent of the aircraft.
- Both aircraft were in a valid state of airworthiness, and weather conditions were favorable for flight.