Two Finnish F-18 Hornets nearly collide with commercial airliner near Tampere

Casualties unknown • FI

Two Finnish Air Force Hornet fighters descended below their assigned altitude, passing within three nautical miles of a Finnair ATR-72 during an approach to Tampere-Pirkkala.

What happened

On March 18, 1997, at approximately 12:30 local time, a serious air proximity incident occurred southeast of Tampere-Pirkkala Airport. Two Finnish Air Force F-18C Hornet fighters, registrations HN-402 and HN-407, were performing a training flight. While descending toward the airport, the fighter pair descended through a previously established minimum altitude of 3,950 meters.

During this descent, the fighters intercepted the flight path of a Finnair ATR-72 (registration AY 5376) traveling from Vaasa to Helsinki. The lead fighter passed the airliner at a distance of approximately three nautical miles, while the wingman passed at approximately five nautical miles. At the same time, a second Finnair Saab SF 340 (AY 4208) was also operating in the vicinity, though it maintained a safe distance from the fighters.

The investigation

The investigation examined radar recordings from Tampere regional air traffic control, flight data from the Hornets, and radio communications. The inquiry focused on the pilots' adherence to altitude restrictions and the air traffic controller's ability to monitor the aircraft. The investigation also reviewed the coordination between the Air Force and air traffic control services.

Findings

  • The pilots of the F-18C Hornet aircraft failed to maintain the required minimum altitude of 3,950 meters. The lead pilot had noted the restriction on a kneeboard but failed to recall it during the descent, while the wingman was focused on following the lead aircraft.
  • The aircraft's altitude warning system was not programmed with the temporary restriction because the process was too complex and time-consuming to perform during an active mission.
  • The air traffic controller failed to notice the fighters descending below their assigned altitude due to a high workload and heavy traffic density in the sector.
  • There was a lack of effective coordination between the Air Force squadron and air traffic control, which hindered the controller's awareness of the military aircraft's specific airspace needs.

Probable cause

The incident was caused by the fighter pilots forgetting a temporary altitude restriction and descending below the assigned minimum, combined with the air traffic controller's inability to monitor the descent due to high traffic volume.

Frequently asked questions

What happened in the 1997-03-18 aircraft accident near FI?

Two Finnish Air Force Hornet fighters descended below their assigned altitude, passing within three nautical miles of a Finnair ATR-72 during an approach to Tampere-Pirkkala.

What aircraft was involved and where did it happen?

The accident on 1997-03-18 involved a aircraft, at FI.

What was the probable cause of the accident?

The incident was caused by the fighter pilots forgetting a temporary altitude restriction and descending below the assigned minimum, combined with the air traffic controller's inability to monitor the descent due to high traffic volume.

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