MELDreamer’s input to the story says that the engine went to full power (post #13).
Many years ago, my airline had that once during engine start on a DC-10. Throttle cable had been moved and misrouted during maintenance, so that the inner cable was in a pulled state at the main engine control end, while the thrust lever on the flight deck was in the normal idle position. One of the rpm's, I think N1, was above 80% and rising before the fuel cut-off was effective, if my memory serves me right. Hair-raising experience, as the Flight Engineer told me when they came back into the office. I think I still remember which F/E.
Back to JED. With brakes off, and given a similar malfunction, a 777 loaded for this short trip might begin to advance against the tug and then break out of line to the side where the tug isn’t. Towbar shear pins snap; the a/c moves further forward. By the time the flight deck is aware that they not only have a runaway engine, but a runaway airplane as well, the tug is hit by the engine inlet. The skid marks on the ramp near the inlet may have to do with the uncommanded turn induced by differential thrust and/or the angle of the nose wheel that was steered by the towbar until shear pin break-off.
So maybe, if you accept the uncommanded accelerating engine, the rest does not appear to be excessively wild phantasy?
Last edited by Plumb Bob; 1st May 2013 at 20:10.