On 18 December 2001, a Saab 2000 being operated by Air Botnia on scheduled passenger flight from Stockholm to Oulu was taxiing out at night in normal visibility in accordance with its ATC clearance when a car appeared from the left on a roadway and drove at speed on a collision course with the aircraft. In order to avoid a collision, the aircraft had to brake sharply and the aircraft commander saw the car pass under the nose of the aircraft and judged the vehicle’s closest distance to the aircraft to be four to five metres. The car did not stop, could not subsequently be identified and no report was made by the driver or other witnesses. The diagram below taken from the official report shows the site of the conflict - the aircraft was emerging from Ramp ‘G’ to turn left on taxiway ‘Z’ and the broken line shows the roadway which is crossed just before the left turn is commenced.
Paths of the passenger car and the aircraft, Source: Swedish AIB Report RL 2003:19e
Once they were notified of the event nearly three weeks after it had occurred, an Investigation was carried out by the Swedish AIB. The Investigation considered a fortunate coincidence that the aircraft commander looked to the left and saw the car approaching since there was no requirement for the flight crew of a taxiing aircraft to be aware of or check activity on airport roads.
The Investigation was concerned at the complete absence of reporting by the car driver and by all the vehicle drivers waiting as required at the opposite side of the road crossing. It also noted that although the Incident had been reported by the flight crew to ATC GND at the time of occurrence, ATC appeared not to have compiled any report on it. Road network, signage, vehicle control and driver authorisation issues were also considered at length by the Investigation.
Findings from the investigation included that:
- The incident car was operated in a manner conflicting with applicable regulations.
- Certain level crossings with the taxi system are unsuitably designed.
- The road system’s signs and signals can be improved.
- Identification of the vehicles can be improved.
- Training and examination for driving permits can be improved.
- Routines for divergence reporting can be improved.
- Systematic monitoring of driving discipline is lacking.
- Statistical follow-up of traffic volumes is lacking.
- The responsibility relationship between vehicle drivers and ATC during LVP is perceived as being unclear.
The Investigation was unable to isolate an unambiguous explanation for the behaviour of the car driver but considered that, more generally, the incident had been the consequence of several independent weaknesses in the interaction between ground vehicles and aircraft at the airport.
Five Safety Recommendations were made as a result of the Investigation, all to the Swedish Civil Aviation Administration in respect of Stockholm/Arlanda Airport in respect of their role as operators of the Airport they should:
- carry out a review of the road system’s signs and signals (RL 2003:19e R1)
- improve the identification system with respect to vehicles (RL 2003:19e R2)
- improve the content of the driving permit training, pedagogy, and examination (RL 2003:19e R3)
- change the existing divergence reporting system to a non-punitive system in the greatest extent possible (RL 2003:19e R4)
- introduce systematic traffic monitoring and traffic follow-up (RL 2003:19e R5)
The Final Report of the Investigation was published on 28 May 2003 and may be seen in full at SKYbrary bookshelf: AIB Sweden Report RL 2003:19e