Introduction
On 14 October 2014 at 15:24 UTC, a dangerous proximity occurred between a Socata TBM 700 (registration DFOOO) and a Canadair Regional Jet CRJ9 (registration OYKFL, operating as SAS2752) in the Warsaw Terminal Control Area (TMA Warszawa) and the Warsaw Control Zone (CTR EPWA). No damage or injuries were reported.
Flight History
The TBM pilot was conducting a flight from Jelenia Góra (EPJG) to Warsaw-Babice (EPBC). The flight plan specified IFR to the WAR waypoint, then VFR to EPBC. At 15:17 UTC, the pilot contacted FIS Warszawa and was observed at 3500 ft descending to 3000 ft. The controller cleared the pilot to descend to 1500 ft QNH 1005 hPa.
At 15:17:33, the controller asked if the pilot was already in VFR flight; the pilot replied that visibility was insufficient. At 15:21:28, the pilot reported visual contact with the ground at 1200 ft AMSL and was instructed to contact AFIS Babice. The aircraft label turned red ("intruder") as it approached the lower TMA boundary (1500 ft).
At 15:21:43, upon receiving weather information from AFIS Babice and lacking visual contact with the runway, the pilot aborted the approach and began climbing. At 15:21:51, at 1600 ft, the aircraft entered Class C TMA Warsaw (from 1500 ft to FL225) and was displayed as an intruder on the approach controller's radar. The approach controller did not react.
By 15:22:43, the TBM had climbed to 2700 ft and initiated a right turn toward a southerly heading, approaching the extended centerline of runway 15/33 at Warsaw Chopin Airport (EPWA).
Air Traffic Control Actions
Meanwhile, SAS2752 had departed from EPWA and was climbing on a standard departure procedure. The approach controller, after receiving information from FIS Warszawa about the intruder, instructed the SAS2752 crew to execute a turn to maintain separation.
Probable Cause and Contributing Factors
The Polish State Commission for Aircraft Accident Investigation (PKBWL) determined the probable cause to be: "Improperly executed missed approach procedure, which led to unauthorized entry into controlled airspace and dangerous proximity with an airliner."
Contributing factors included the absence of safety barriers in the Pegasus_21 radar system – specifically, no Short Term Collision Alert (STCA) generation for altitudes between 0 and 4000 ft within approximately 12 NM of EPWA – and the raising of the CTR EPWA altitude to 4000 ft to avoid false intruder alerts for approach control positions.
The commission issued two safety recommendations to the Polish Air Navigation Services Agency.