The Cause of the accident was because the crew flew the aircraft into the ground. The Safety Altitude was 5,900 feet. The aircraft impacted at 810 feet Therefore it was below the Safety Altitude. Why didn't they take avoiding action? Did they see the Mull of Kintyre? If they did see it why didn't they avoid it? If they didn't see it , why didn't they see it? Were they looking out? Were they clear of cloud? - Quite probably although that has not been determined. Were they in sight of the surface? Well if they could see the surface they why did they fly into it? If they couldn't see the surface then what were they doing about not being able to see the surface when they knew exactly where they were and they knew that they were below the SALT?
But they were not grossly negligent.