What happened
On October 14, 2014, a Socata TBM 700 (registration DFOOO) was conducting an IFR flight from Jelenia Góra to Warsaw-Babice. During the approach to Warsaw-Babice, the pilot was informed by the airport information service (AFIS) that weather conditions were unsuitable for landing. Consequently, the pilot aborted the descent and began a climb.
During this climb, the aircraft entered the Warsaw TMA and subsequently the Warsaw CTR airspace. Simultaneously, a Canadair Regional Jet (CRJ9), operating flight SAS2752 for Scandinavian Airlines, was performing its departure procedure from Warsaw-Chopin Airport (EPWA). As the Socata TBM 700 continued its ascent and turn, it entered a path that led to a loss of both lateral and vertical separation from the departing jet. The separation fell below the required 3 NM and 1,000 ft. The air traffic controller (APP) eventually instructed the crew of the CRJ9 to execute a turn to restore separation after being alerted to the conflict by the FIS controller.
The investigation
The PKBWL investigation examined the flight paths, radar data from the Pegasus_21 system, and the configuration of the air traffic management software. The investigation established that the pilot of DFOOO did not have the required authorization to conduct the flight under IFR procedures. Furthermore, the investigation looked into why the radar system failed to trigger a Short Term Collision Alert (STCA) during the encounter.
Findings
- The primary cause of the incident was the improperly executed departure procedure following an aborted landing, which resulted in unauthorized entry into controlled airspace and a dangerous proximity to a commercial aircraft.
- The pilot of the Socata TBM 700 failed to establish radio contact with air traffic control services.
- A critical lack of safety barriers existed within the Pegasus_21 radar system. Specifically, the STCA function was disabled between 0 and 4,000 ft within a 12 NM radius of Warsaw-Chopin Airport to prevent false alarms.
- The system configuration had artificially raised the boundary of the Warsaw CTR airspace to 4,000 ft in the software to avoid generating "intruder" alerts for the approach controller, which effectively degraded the ground-based safety net.
Safety action
- The Commission reiterated a recommendation to the Polish Air Navigation Services Agency (PAŻP) to reactivate STCA warnings within the 0 to 4,000 ft altitude range and 12 NM radius of EPWA, while carefully parameterizing the system to minimize false alarms.
- A recommendation was made to modify the Pegasus_21 system to ensure it generates proper airspace violation alerts ("intruder" alerts) for the APP controller within the Warsaw TMA.