What happened
On August 14, 2013, at approximately 09:58 UTC, a collision occurred near the Hosín airfield (LKHS) involving a LAK 12 glider, registration OK-1212, and the tow rope of a Rallye 180T-D aircraft, registration D-ESKH.
The incident began when the pilot of an ASTIR CS Jeans glider, being towed by the Rallye 180T-D, observed another glider approaching on a collision course. To avoid a mid-air collision, the towed pilot released the tow rope and immediately began a climb. However, the trailing rope, having whipped after the release, struck the LAK 12 glider, which was flying in the vicinity. The impact of the rope was forceful enough to puncture the lower part of the LAK 12 fuselage.
The pilot of the LAK 12 reported hearing loud engine noise and seeing the aircraft approaching from the left before the impact. Following the strike, the pilot of the LAK 12 performed a series of checks on the flight controls and, after receiving confirmation from air traffic services that no visible damage was apparent from the ground, landed safely at LKHS. There were no injuries resulting from the event.
The investigation
The ÚZPLN investigation analyzed GNSS flight data from both gliders to reconstruct the trajectories of the aircraft involved. The investigation examined the relative positions, speeds, and headings of the LAK 12, the towed glider (OE-5165), and the Rallye 180T-D in the minutes leading up to the collision. The investigators also reviewed pilot statements and meteorological conditions, which were found to be clear with good visibility (CAVOK).
Findings
- The pilot of the Rallye 180T-D failed to identify that its flight path was intersecting with the path of the LAK 12 glider approaching from the right.
- The pilot of the LAK 12 likely failed to see the approaching aero-tow due to the aircraft's position and cockpit visibility constraints, only noticing the aircraft upon hearing the engine noise.
- The primary cause of the collision was the improper distribution of attention by the pilot of the towing aircraft, who likely focused on the glider being towed rather than scanning the surrounding airspace.
- The towed glider pilot acted correctly by releasing the rope to avoid a collision with the LAK 12.