What happened
On January 29, 2003, at Kuusamo Airport, a near-miss occurred between a charter airliner and a runway maintenance vehicle. The aircraft, a Boeing 737-300 operating as AXY852 for Axis Airways, was arriving on a flight from Paris. Due to heavy fog, the runway visual range (RVR) had dropped below 1500 meters, prompting the Flight Information Service Officer (FISO) to authorize a maintenance vehicle, Lento 30, to move to the runway threshold to measure visibility.
As the aircraft commenced an ILS approach to runway 12, the flight crew failed to report their arrival into the flight information zone or communicate their intentions to the FISO. Confusion arose during radio communications because the crew's position reports were incomplete or missing. Furthermore, the FISO misinterpreted a transmission regarding the aircraft's position relative to the KS VOR, mistakenly believing the plane was departing the area rather than approaching. Consequently, the aircraft landed without receiving a "runway free" clearance. The Boeing 737-300 passed over the maintenance vehicle at a vertical distance of approximately 15-20 meters.
The investigation
The investigation examined the actions of both the flight crew and the airport staff. It established that the crew did not follow the procedures outlined in the Finnish Aeronautical Information Publication (AIP) regarding operations at AFIS aerodaries. The investigation also scrutinized the FISO's performance, noting that the officer's decisions were partially based on assumptions. The investigation found that the FISO did not request clarification for radio transmissions that were unclear or difficult to understand due to the crew's heavy French accent.
Findings
- The primary cause of the incident was that AXY852 failed to report its arrival in the flight information zone and its intentions, and failed to provide mandatory position reports, leading to the aircraft landing on a runway occupied by a vehicle.
- The flight crew lacked a clear understanding of how air traffic services are organized at Finnish AFIS aerodromes.
- The FISO experienced difficulty understanding English communications spoken with a strong French accent and did not ask the pilot to repeat unclear messages.
- The FISO's operational picture was compromised by making assumptions regarding the aircraft's flight path.
- Environmental factors, such as fog caused by ground inversion and aircraft wake turbulence, significantly reduced visibility during the approach.