The aircraft was a Beech 55 Baron and departed Inverness climbing to flight level 70. With the prevalent weather conditions I'd hazard a guess an IFR approach was being made into Dundee. The pilot, who was also a commercial pilot, had flown into Dundee on numerous occasions and had a lot of experience flying around the Highlands & Islands of Scotland in various aircraft types, both VFR and IFR, in much more adverse and severe weather conditions.
RIP Silverknapper