What happened
On April 22, 2001, a Finnair Airbus A3/19, operating as FIN 822 F, entered a restricted airspace area at Malmi during its approach to Helsinki. The aircraft was on a scheduled flight from Frankfurt to Helsinki. Due to existing airspace restrictions, including an active military firing area, the Helsinki Approach controller (APP) had coordinated a specific route to bring the aircraft to Helsinki via a direct path.
At the time of the incident, Malmi Tower (TWR) had authorized parachuting activities. While the aircraft was performing its approach, several skydivers were in the air, including two individuals performing high-altitude openings at approximately 1,000 meters. The aircraft passed through the boundary of the parachuting zone at an altitude of approximately 2,628 feet, coming as close as 1.1 NM to the skydivers.
The investigation
The investigation examined the sequence of communications between Helsinki Approach, Malmi Tower, and the aircraft crew. Investigators reviewed radar data, flight recorder information, and radio communications. The investigation focused on the coordination between the different air traffic control units and the accuracy of the readbacks provided by the flight crew.
Findings
- The incident resulted from a series of consecutive errors rather than a single cause.
- The flight crew performed an incorrect readback of a Tower instruction; when the Tower stated "Call you back," the crew responded with "One circle right."
- Malmi Tower failed to detect this incorrect readback.
- The Tower provided an imprecise instruction to the crew, stating "Turn slightly right" instead of the specific instruction from Approach to turn south.
- The Approach controller changed the aircraft's flight path instructions in very short intervals, making the flight path uncontrollable from a control perspective.
- There were delays in the delivery of evasive instructions due to the Tower transferring the aircraft to a different frequency without providing the necessary radio frequency information.
- The aircraft's entry into the restricted zone was unavoidable due to the cumulative delays in communication and the rapid changes in instructed headings.