C9/2007L An unauthorized approach to an engaged runway at Pori aerodrome on 7 November 2007

An incident occurred on 7 November 2007 at 20:23 UTC (Finnish time -2h) at Pori aerodrome, involving a Pegasus Airlines Boeing 737 charter flight from Copenhagen and an aerodrome maintenance vehicle. Accident Investigation Board Finland (AIB) appointed investigation commission C9/2007L for this incident. Investigator Markus Bergman was named Investigator-in-Charge with Investigator Erkki Kantola and Air Accident Investigator Tii-Maria Siitonen as members of the commission.

As the aircraft was approaching Pori, a maintenance vehicle was assessing the Runway Visual Range (RVR) by counting the number of visible runway lights on the active runway. The air traffic controller reported the RVR to the pilots. Because the RVR was below the landing minimum he cleared them to a holding pattern to wait for RVR to improve. However, the pilots were of the impression that they were permitted to continue the approach to the Decision Altitude (DA) of the ILS approach. The misunderstanding between the air traffic controller and the pilots resulted in a collision hazard between the vehicle and the aircraft.

The incident occurred because the pilots flew the approach without the required ATC clearance. Unsatisfactory and unclear radio communications between the air traffic controller and the flight crew were contributing factors. Another contributing factor was that the pilots violated regulations by continuing with the approach even when the reported RVR was below minimum.

The investigation commission did not make any recommendations because present rules and regulations, if properly observed, suffice in preventing these kinds of incidents from taking place.

C9/2007L Report (pdf, 0.78 Mt)