What happened
On June 25, 2019, at 08:34 UTC, an EC-135 helicopter, registration SP-HXS, operating as a HEMS (Helicopter Emergency Medical Service) mission for LPR, departed Babice (EPBC) for a medical call in Gniaty-Wieśniany. Prior to departure, the pilot established contact with the Warsaw-Babice Flight Information Service (FIS) and was informed of a Cessna 152 performing a single circuit at 1,500 ft on an easterly course.
After completing the first turn and turning onto a northerly heading, the crew observed a Cessna 172 on their right side. The aircraft was flying along the Vistula River at the same altitude, approximately 50 meters from the helicopter. The near mid-air collision occurred in the vicinity of the ZULU waypoint within the Babice ATZ.
The investigation
The PKBWL investigation examined radar imagery and Flight Information Service (FIS) correspondence provided by PAŻP. Following the incident, the helicopter crew notified the Babice FIS duty officer via telephone. The duty officer confirmed that there had been no prior information regarding the presence of a Cessna 172 in the area.
Investigators attempted to identify the Cessna 172 using available radar and communication records, but the aircraft could not be identified. The investigation established that the aircraft was operating without radio communication and had its transponder turned off, rendering it invisible to radar surveillance.
Findings
- The primary cause of the incident was the failure of the Cessna 172 to comply with air traffic rules within the Babice ATZ.
- The unidentified aircraft failed to establish radio contact with the Babice FIS.
- The aircraft was operating with its transponder deactivated, preventing radar identification.
- Separation between the two aircraft was the responsibility of the crews, as the airspace was under FIS control.