South African Airways flight 406, a Vickers Viscount, crashed into the sea while on approach to East London Airport, South Africa, killing all 25 occupants. Vickers Viscount ZS-CVA, named “Rietbok”, was on a scheduled public transport flight SA406 from Port Elizabeth to Johannesburg via East London and Bloemfontein, South Africa. At Port Elizabeth crew took on board 2,000 lb of fuel in excess of the normal sector fuel uplift, on the basis that they may had to overfly East London and proceed to Bloemfontein due to poor weather at East London. The flight made a normal takeoff from Port Elizabeth at 16:41 UTC and climbed to Flight Level 90. At 16:58 UTC the aircraft contacted East London Airport Control and was given a weather report: 8/8ths Nimbo Stratus at 200 feet to 300 feet overhead, lowering on the approaches to runway 28; continuous drizzle; visibility 3/4 of a mile; ground temperature plus 16øC.; QNH 1025. At 16:59 UTC the aircraft acknowledged the weather and requested descent clearance from Flight Level 90. Clearance was given by East London Tower and acknowledged. At 17:07 UTC the flight was cleared for a runway 10 approach. The last radio transmission was at 17:09 UTC when the flight reported at 2000 feet with the coast line in sight. The airplane impacted the sea at high speed about 17:10 UTC. Bits of floating wreckage, consisting mainly of cabin interior fittings, were recovered by naval vessels and other pieces were washed ashore. The main wreckage of the aircraft is believed to he lying at a depth of between 180 and 220 feet, approximately 1« miles off-shore. Extensive salvage operations were attempted, but were hindered by murky water, a current up to 8 kts. and dangerous sea conditions. PROBABLE CAUSE: “The available data is not sufficient for the originating cause of the accident to be determined with any degree of probability. In the opinion of the Board certain possibilities can be excluded as being consistent with the evidence and/or as being remote and improbable; among these possibilities are structural failure, failure of the controls, or control surfaces, multiple engine failure, instrument failure, explosion, fire, a ‘bad weather’ accident and pilot error. However, on the evidence the Board cannot exclude as the originating cause of the accident a heart attack suffered by the captain in the air, with ensuing loss of control of the aircraft, and with the first officer being unable in the time available to regain sufficient control to prevent contact with the sea.” It was later rumored that the aircraft crashed as a result of a structural failure, because comparable accidents happened during that time.