although wasn't SAA 747 brought down years ago in the Indian Ocean by a cargo hold fire with large loss of life?
It was a 747SP Combi. There was a long government cover up with the usual conspiracy theories, eventually when apartheid ended the Truth and Reconcilliation Commission confirmed that the aircraft was carrying a secret shipment of solid fuel rocket propellant for a missile project. Interestingly this could not have been the original cause of the fire because it would have destroyed the aircraft in seconds rather than the time that they flew an attempted diversion. It is likely that a minor fire spread slowly until it reached the dangerous cargo.
Google for "Helderberg disaster" if you have a few hours to spare wading through the crackpot theories.