With the testimony of five separate witnesses as to noise, we assume something of importance was happening as early as liftoff. It may have been a closing of the power levers, an attempt to reject takeoff. That this noise signature apparently coincided with a “turn” is potentially the key to what happened. Losing boost, or boost locked controls are trained in this type exhaustively, that is why the unlocking/relocking of boost levers is at the base of the pedestal, with the takeoff checklist demanding the access flip door be open on launch. I am wondering why the pumps are not shut down as part of the procedure?