What happened
On June 24, 2015, at 14:43 UTC, a Cessna 182 entered the MATZ EPTM controlled airspace without authorization while military W-3 Sokół helicopters were performing IFR instrument approach training in the area. The pilot of the Cessna 182 had initially reported a flight plan from EPBCF to EPKM, intending to bypass the MATZ zones. However, the aircraft deviated westward from its planned route, penetrating the BRAVO and CHARLIE sectors of the MATZ.
During the incident, a military W-3 Sokół helicopter was conducting a simulated IMC approach. The crew of the helicopter observed the unauthorized white aircraft at an altitude of approximately 700 m. Radar data indicated that at the moment the Cessna 18 and the helicopter were on converging tracks, they came within a minimum distance of approximately 0.32 NM (600 m) with a vertical separation of only 200 ft.
The investigation
The investigation examined radar logs from the Pegasus P_21 system, radio communications from FIS Warszawa, and the operational environment of the air traffic information service. The investigation established that the FIS Warszawa controller was managing heavy, dispersed traffic, which required frequent repetitions of instructions due to poor radio signal quality at low altitudes.
Furthermore, the investigation looked into the handover process between controllers. It was found that during the shift change, the incoming controller was informed that the Cessna 182 pilot was "arranging flight through [the zone] with Tomaszów," which led to the assumption that no further intervention or monitoring was required. The investigation also analyzed the technical limitations of the radar display and the lack of Short Term Conflict Alert (STCA) in the uncontrolled Class G airspace.