Now four months on, families of the deceased are crying out for an explanation. So what happened?
Investigators have so far only managed to rule out a terrorist attack as the cause, saying that everything else can only be a matter of informed speculation and that the real answers are locked in the aircraft's black box flight recorders.
However, these are now lost at the bottom of the ocean and even if it is possible to retrieve them they may have been damaged, and rendered useless.
As reporter Andrew Fowler has discovered, there is growing circumstantial evidence that there may have been significant equipment failures aboard.
Eight relatives have just announced they are suing Airbus for negligence in the US and more legal action is expected.
Relatives fear the truth is being suppressed and that the puzzle may never be satisfactorily resolved.
This episode of People & Power aired from Wednesday, November 25, 2009.