On 29 August 2006, a DHC-6 being operated by Loganair on a scheduled domestic passenger flight from Campbeltown to Glasgow which had just landed on runway 27 commenced a daylight backtrack in normal ground visibility towards the terminal and after stopping at the holding point prior to the intersection with the main active runway 23 for a short period then began taxiing again as a British Regional Airlines Embraer ERJ145 was about to touch down, only stopping and powering backwards and clear at a late stage.
An Investigation was carried out by the UK Aircraft Accident Investigation Branch (UK) (AAIB). It was established that the DHC6 had been cleared by ATC to continue the back track beyond holding point Y1 and across runway 23 only after the landing aircraft had passed the intersection. It was reported by the aircraft commander of the DHC6, who had been taxiing the aircraft, that having stopped as cleared, he had initiated a ‘heads down’ discussion on tat Y1 raining issues with his First Officer. On completing this, he had assumed that the landing aircraft had passed and resumed taxiing until, as the aircraft was about to enter the runway, he caught sight of the other aircraft about to touch down. He had immediately reversed the aircraft back towards the holding point.
It was found that although the other aircraft had seen the DHC6 shortly before touchdown, it had appeared to be stationary and so they had no cause for concern.
It was noted that the TWR controller had Surface Movement Radar available and that this display was overlaid with a RIMCAS (Runway Incursion Monitoring and Confliction Alerting Sub-system) defined area which was selectable as either or both runways active or as ‘crossing mode’ for runway 05/23 and crossing traffic using runway 09/27. Since visual rather than Low Visibility Procedures (LVP) conditions had prevailed, the RIMCAS was selected to visual mode and the information generated was advisory only. However, the appropriate ‘crossing’ mode had not been selected and so no RIMCAS activation had occurred as the DHC6 breached its clearance and crossed the Y1 Holding Point. It was found that neither the TWR controller involved nor his colleagues had understood the difference in protected area between the crossing mode and the single runway mode selected.
Safety Action was taken by ANSP NATS as a result of the incident to both ensure correct controller understanding of the RIMCAS modes and to extend the protection for the single runway 05/23 mode along the cross runway in both directions as far as the respective holding points.
The formal Conclusion of the Investigation was that: "Whilst holding on the north side of the active runway the DHC-6 commander sought to illustrate his training points to the co-pilot. By being ‘head down’ on the flight deck he became distracted and lost his sense of time and situational awareness regarding the landing Embraer 145. He concluded that if debriefing points needed to be illustrated, this was best conducted once the aircraft was parked and the engines shut down."
The Final Report of the Investigation was published on 8 March 2007. No Safety Recommendations were made