The Wadi Halfa Airport has a single unpaved "compacted sand" 2000m runway. Given the Viscount's English origins, I would guess it would have operated off turf runways.. Just a guess.
Here are links to the crash of a Central African Airways Viscount scheduled flight from Wadi Halfa to Libya on 9th August, 1958.
1958 Central African Airways plane crash - Wikipedia, the free encyclopedia
ASN Aircraft accident Vickers 748D Viscount VP-YNE Benghazi-Benina International Airport (BEN)