What happened
On the evening of November 5, 2002, a night navigation training flight was underway in a Cessna 172, registration SE-IBX. The flight, consisting of a student pilot and an instructor, was traveling from Hagshult toward Gothenburg/Säve airport. During the flight, the crew contacted Gothenburg Control to report their position and altitude.
As the aircraft progressed northwest of the Landvetter control zone, the pilots observed another aircraft to their right that appeared to be turning toward them. Simultaneously, the crew heard a transmission from the pilot of an Airbus 320, registration TS-INC, stating that a TCAS warning had been received and a climb had been initiated to avoid traffic. To ensure safety, the pilots of SE-IBX reduced power and descended to 2,500 feet. The two aircraft eventually passed within approximately 117 meters horizontally and 300 meters vertically.
The investigation
The Swedish Accident Investigation Board (SHK) determined that SE-IBX had entered the Gothenburg/Landvetter terminal area without receiving proper clearance. The investigation focused on why the air traffic controller failed to identify the encroachment.
Investigators found that the radar presentation settings were configured with the "OTH OFF" function, which suppressed labels for other traffic in the area. Additionally, the controller had not manually programmed the SE-SBX flight into the radar system. While the controller had obtained the flight strip for the aircraft, the lack of active radar labeling contributed to the oversight.
Findings
- The primary cause of the incident was a misunderstanding between the air traffic controller and the pilot of SE-IBX.
- The air traffic controller was using a radar presentation mode that omitted labels for controlled and uncontrolled traffic.
- The controller had not entered the specific flight data for SE-IBX into the radar system.
- SE-IBX operated within the controlled terminal area without explicit authorization.
- Deficiencies in air traffic control routines and phraseology contributed to the loss of separation.