C10b/2002L Loss of Separation in the Turku Terminal Area on October 31, 2002

On Thursday 31 October 2002 at 16.37 local time there was an aircraft incident approximately 43 km west-south-west of Turku airport. An Air Botnia Oy Avro RJ85, call sign KFB662 on a scheduled passenger flight from Copenhagen to Turku, and an European Executive Express Jetstream 32, call sign EXC316 on a scheduled passenger flight from Turku to Mariehamn, passed each other at an altitude of about 2500 m with opposite headings and the separation was lost. The pilots of KFB662 noticed EXC316 on their TCAS display, aborted their descent and remained level at flight level 85. Also the pilots of EXC316 noticed the opposing traffic on their TCAS display and maintained their cleared flight level 80. The commander of KFB662 obtained visual contact with the lights of EXC316 6-7 seconds before the aircraft passed each other. The Accident Investigation Board Finland decided on 11 November 2002 to investigate the incident and appointed airline pilot Jussi Haila as the investigator-in-charge. MSc Ville Hämäläinen and air traffic controller Erkki Lepola were appointed as members of the investigation commission.

At the time of the incident the traffic was handled by an air traffic controller student of Avia College who was on an on-the-job training period. The air traffic controller on duty had moved to a distance of approximately 2-3 metres from the working position and dictated the clearances which the student relayed to the aircraft. EXC316 had received an enroute clearance from Turku to Mariehamn at flight level 80. KFB662 had received a clearance to descend to flight level 100 from Tampere Area Control Centre and contacted Turku when instructed by the ACC when approaching flight level 100 at a distance of approximately 65 km. The air traffic controller dictated to the student a clearance for KFB662 to TURKU via PERKA 3B arrival and to descend to 3200 feet on QNH 1011. The student relayed the clearance to the aircraft. The air traffic controller had forgotten the departing EXC316 and cleared KFB662 to descend through the altitude of EXC316. He did not notice the mistake before KFB662 asked about the opposite traffic the pilots had noticed on the TCAS (Traffic alert and Collision Avoidance System). The air traffic controller started to handle the traffic after the question but it took a while before the situation was under his control. The student was not in an educational situation to handle traffic in the working position nor was it permitted by Avia College guidelines. She also had no possibility to detect the conflicting clearances based on her education. The air traffic controller did not use the flight strip markings made by the student nor the radar monitor in the control tower, but operated based on his memory and the radio traffic from the loudspeakers.

The minimum vertical separation between the aircraft was 500 feet (150 m) without the required horizontal separation. KFB662 climbed back to flight level 90 before the aircraft passed each other and the vertical separation was the required 1000 feet. There was no danger of collision due to the vigilance of the KFB662 pilots.

The investigation commission recommended that the Finnish Civil Aviation Administration and Turku airport would develop an administrative model aiming to the safety of operations. The commission also recommended that the radar monitor would be more actively used and better located in Turku. It was also recommended to formulate on-the-job training guidelines and schedules and nominate on-the-job trainers in Turku. The commission recommended that Avia College would prepare a co-operation agreement with Turku airport. The comments received for the draft report have been taken into account in the final version.

C10b/2002L Report (pdf, 0.2 Mt)