Proximity Alert Involving Boeing 737-800 and Embraer 190 in Warsaw FIR

Incident Overview On 14 April 2015, a proximity alert was generated in the Warsaw Flight Information Region (FIR EPWW) near the SABAB navigation point. The incident involved a Boeing 737-800 (B738) and an Embraer 190 (E190). The B738 was climbing after departure from EPKK via BINKA toward FL 360, while the E190 was en route from ELVOT to AGAVA at FL 350. ## Sequence of Events After contacting ACC T, the B738 was cleared to climb to FL 340. The air traffic controller, after confirming separation from the E190, then cleared the B738 to FL 360. During the climb, the B738's speed decreased by approximately 30 knots, likely due to strong wind, which reduced the distance between the aircraft and triggered a red STCA alert. ## Investigation Findings The investigation determined that the separation between the aircraft was not reduced below required standards. The controller was on their second duty shift after two days off, and traffic was at the upper limits of sector capacity. The controller held valid qualifications and had completed a refresher course in November 2014. The incident was reclassified from an air traffic incident to an event due to identified errors in ATM operations. ## Outcome No cause was determined. The investigation was completed on 2 October 2015. The final report was to be shared with the involved controller and the ATS Training Centre for use in training materials. No safety recommendations were issued.