[TalBlack]

Why not a latter day version of A Comet (BOAC) failure? Some fault as yet unknown which brings about sudden absolute failure of the plane? Something in the timeline preclude this? Or is it unlikely as hell in the CAD/testing age?

[Izzy Dunne]

Some fault as yet unknown which brings about sudden absolute failure of the plane?

A "suitcase" nuke, put aboard by the stolen-passport guys from Iran:

• Triggered by 1 hour after takeoff, or maybe reaching cruise altitude, or by accident.
• Blows plane into dust - no debris big enough to be found.
• No transponder, no engine health monitor.
• No more signal echo to ground-based radar, or other aircraft radar.
• No warning to passengers, crew or ground.

Would that be detectable from land-based stations? Vietnam and Malaysia might not be up for it.

Detectable from U.S. satellites ? I don't know. It wouldn't have to be huge (megatons). < / speculation >