What aircraft was involved and where did it happen?

The accident on 2002-10-23 involved a aircraft, registration OH-KRA, at FI.

What was the probable cause of the accident?

The loss of separation was caused by the departing aircraft's failure to adhere to a specific altitude restriction during its initial climb, compounded by a misunderstanding of the air traffic control clearance.

Loss of Separation Near Turku Airport

A Gulfstream G100 climbing from Turku, Finland, passed through the altitude of an approaching ATR-72-201, resulting in a near-midair collision.

What happened

On October 23, 2002, at 14:10 UTC, a separation loss occurred east of Turku Airport, Finland. A Gulfstream G100 (registration HB-VNF), operating a private flight from Turku to Bern, Switzerland, was climbing out from runway 08. Simultaneously, a Finnair ATR-72-201 (registration OH-KRA), operating flight FIN229, was on a visual approach to the same runway from the east.

The air traffic controller had issued an initial climb restriction to HB-VNF, instructing the crew to maintain 3,200 feet until reaching the 236 radial of the RUSKO VOR/DME. However, the crew of the Gulfstream G100 continued their climb beyond this altitude. As a result, the aircraft passed through the 4,200-foot altitude assigned to the approaching ATR-72-201. At the moment of the altitude breach, the horizontal distance between the two aircraft was approximately 1.8 nautical miles. While the pilots of the ATR-72-201 observed the departing aircraft on their TCAS displays and through the cockpit window, the low sun angle prevented them from seeing the Gulfstream G100 visually until it had risen above the horizon.

The investigation

The investigation focused on the communication and understanding of the climb restrictions. It was established that while the first officer of HB-VNF had correctly read back the clearance, the crew failed to understand the 3,200-foot restriction. The captain stated they believed they were permitted to climb on the runway heading to 3,200 feet before turning. The investigation also examined the air traffic controller's actions, noting that the controller intended to waive the separation once both aircraft were clearly visible, but had not provided traffic information to the approaching aircraft.

Findings

The primary cause of the incident was that HB-VNF failed to comply with the assigned 3,200-foot initial climb restriction, resulting in the aircraft passing through the altitude of the approaching ATR-72-201.
A contributing factor was the lack of traffic information provided to the crew of FIN229; although not strictly required for separated aircraft, the investigation noted that providing such information would have constituted good air traffic service.
The crew of HB-VMA did not properly utilize the altitude alerter, which would have alerted them to the approaching restriction if the 3,200-foot limit had been correctly programmed.
The use of Finnish language for certain communications caused confusion for the international crew of the Gulfstream G100.