Description

On 15 October 2011 a Saab 340 being operated by Loganair on a scheduled cargo flight from Aberdeen to Stornoway was inbound on a procedural non precision approach to runway 18 in day Instrument Meteorological Conditions (IMC) and level at 2000 feet Altimeter Pressure Settings when it received a TCAS RA ‘DESCEND’ against opposite direction traffic level at the same altitude and responded accordingly. The other aircraft was also being operated by Loganair on a scheduled passenger flight from Inverness to Stornoway and was outbound on the same procedural non precision approach. The inbound aircraft flew a go around following the avoidance manoeuvre and the second aircraft completed the procedure and landed.

Investigation

An Investigation was carried out by the UK Airprox Board. It was noted that the incident had occurred in uncontrolled airspace and with only procedural ATS available and with APP and TWR duties being performed by one controller and an assistant.

It was noted that the procedure being flown by both aircraft (see the diagram below reproduced from the official report) was the Runway 18 LOC/DME/NDB(L) procedure involving a DME at the threshold.