What happened
On January 7, 1998, at approximately 08:20 UTC, a near-collision occurred at Helsinki-Vantaa Airport during taxi operations under CAT2 low-visibility conditions. The incident involved two Finnair aircraft: an MD82 (registration OHLMN), operating flight FIN 644, and an ATR-72 (registration OHKRD).
The ATR-72 was taxiing from stand 13 toward a test site under the supervision of a maintenance mechanic. Simultaneously, the MD82 was completing a CAT2 approach to runway 22. As the MD82 exited the runway via taxiway Q, its path intersected with the path of the ATR-72, which was taxiing on taxiway 1.
Due to the heavy fog, which reduced meteorological visibility to only 150 meters, the flight crews were unaware of each other's positions. The pilot of the MD82 observed the ATR-72 approaching from the left and applied braking to avoid a collision. The ATR-72 crew also observed the MD82 and decided to slightly increase speed to pass in front of the larger aircraft to avoid disrupting its movement. The incident was reported to the Tower and Ground controllers immediately after the encounter.
The investigation
The investigation examined the actions of the aircraft crews and the air traffic controllers at both the Tower and Ground workstations. The investigation established that the aircraft were operating on different radio frequencies, which prevented direct communication between the two movements.
Investigators found that the Tower controllers, consisting of a trainee and a trainer, had lost track of the ATR-74's movement and were not monitoring the surface movement radar. Furthermore, the Ground controller had no radar display available at the time of the incident. The investigation also noted that the maintenance mechanic conducting the taxi training for the ATR-72 was not sufficiently trained in standard aerodrome movement rules or right-of-way regulations.
Findings
- Lack of coordination: There was a failure in proactive coordination between the Tower and Ground control sectors regarding traffic crossing the boundaries of their respective areas of responsibility.
- Inadequate monitoring: Air traffic controllers failed to utilize surface movement radar effectively, and the Ground workstation lacked a radar display entirely.
- Ambiguous instructions: The instructions regarding coordination between different control workstations during low-visibility operations were not sufficiently clear.
- Crew awareness: The near-collision was avoided only due to the active environmental monitoring by the flight crews of both aircraft.
- Training deficiencies: The maintenance mechanic's training for taxi qualifications did not include essential knowledge of aviation laws or right-of-way rules.