Let's not forget two other terrible CFIT accidents involving turboprops belonging to British IT charter airlines in the 1960's and early 1970's: British Eagle Britannia G-AOVO near Innsbruck in winter 1963/64; and the Invicta Vanguard G-AXOP near Basel in April 1973. CFIT accidents were all too prevalent in those days, and certainly not restricted to piston-engined aircraft.
The Invicta accident was especially notorious, and apparently involved a significant amount of spatial disorientation on the part of the crew, while attempting an NDB approach to minimums in a snowstorm. This accident was especially tragic as the aircraft was chartered on behalf of a group of country ladies from Somerset for a day visit to Basel, most of whom had never flown before.