What happened
On October 7, 2000, a loss of separation occurred near Helsinki-Vantaa airport during the final approach to runway 04. The incident involved two Finnair aircraft: an ATR 72 (registration OH-KRK) operating a training flight (callsign FIN9801) and a DC-9-51 (registration OH-LYZ) operating a scheduled flight from Warsaw (callsign FIN742X).
The crew of the ATR 72 was performing an instructor-led training flight. After completing a landing and a second circuit, the aircraft was instructed by the Tower controller to fly through the final approach course to join the right base for runway 04. At the same time, the DC-9-51 was on an ILS approach to the same runway.
As the ATR 72 crossed the final approach course, it was approximately 1.2 NM from the centerline of the DC-9-51. The minimum distance between the two aircraft reached approximately 1.1 NM. The crew of the DC-9-51 observed the ATR 72 crossing their path, while the ATR 72 crew did not realize a conflict had occurred until after the encounter. No injuries or aircraft damage were reported.
The investigation
The investigation examined radio and telephone communications, radar recordings from both the noise surveillance radar and the MSSR radar, and the operational procedures of both the Tower and Arrival controllers. Investigators also reviewed the airline's training manuals and the coordination agreements between different air traffic control sectors.
Key elements examined included the visibility conditions, which were impacted by sunlight reflecting off clouds, making visual monitoring difficult. The investigation also looked into the specific instructions given by the Tower controller regarding the flight path of the training aircraft and the coordination (or lack thereof) between the Tower and Arrival sectors.