What happened
On the evening of December 15, 1999, a serious runway incursion occurred at Vaasa Airport. A Finnish Air Force Hawk Mk 51 (registration HW-334) was performing a night navigation training flight under visual flight rules. The aircraft was executing a touch-and-go maneuver on runway 16.
Simultaneously, an Embraer EMB-110 Bandeirante (registration LN-TDY), operated by Reguljair Ab, was taxiing. The crew of the Embraer 110 had been cleared to hold at position Bravo, but the aircraft failed to stop at the holding point and instead continued taxiing onto runway 34. As the Hawk Mk 51 completed its touch-and-go, it passed over the Embraer 110 at an altitude of approximately 50 meters.
The investigation
The investigation examined the radio communications and environmental conditions at the time of the event. It was established that the aircraft were operating in darkness with intermittent patches of surface fog. The investigation also reviewed the radio telephony between the aircrews and the air traffic controller, noting that two different languages were in use: English for the Embraver 110 and Finnish for the Hawk Mk 51.
Findings
- The crew of the Embraer 110 forgot their assigned holding instruction and taxiied onto the active runway in violation of their clearance.
- The crew of the Embraer 110 did not understand the Finnish-language communications between the air traffic controller and the Hawk Mk 51, which prevented them from realizing a military aircraft was performing a touch-and-go on the airfield.
- The darkness and surface fog prevented both flight crews from visually detecting the other aircraft.
- The air traffic controller observed the incursion but did not realize the Embraer 110 had passed the holding point until the crew queried their takeoff status.
- The Hawk Mk 51 performed its maneuver according to its assigned clearance, unaware of the unauthorized runway occupancy.