Seeking ID of fatal accident South Africa 8 Dec 1977

Kiwi pilot Alan Charles Dunbar died in aircraft accident in South Africa on 8 Dec 77 when engaged on a flight from Pietermaritzburg and Ladysmith, Natal province.

Can anyone provide an ID for the aircraft in which he (and others?) was killed or any other info about the accident, please? (Have checked ASN website but no mention found there.)

TIA,
Errol