On Friday, 12 December 2014 14:34:10 UTC, JJ Sinclair wrote:
Sounds like Ivan/Eagen accident in a Nimbus 4M that shed the outboard wings in a spiral dive. I have always thought it was a case of "Who's flying this machine".................Think about it...................I think you are flying, you think I am flying, truth is nobody is flying the machine. The 'un-flown' machine stumbles into a strong shear and drops a wing.............I think you are entering a thermal, you think I am entering a thermal. Nose of this un-flown machine drops and suddenly we are BOTH FLYING the machine!

Always shake the stick and say, "I have the aircraft"

RIP, guys
JJ

Very strange that the witnesses reported hearing engine noise. I would not expect to combine engine operation with any mode of flight which would result in uncontrolled departure.