October 8, 1947

Chuck Yeager flies the XS-1, tail #46-062, on USAF/Yeager's 7th powered flight. Yeager reaches MACH 0.925 Purpose: Airspeed calibration flight.

HOWEVER, Yeager loses control of the airplane.

The sound barrier's shockwave lays down on the hinge of the horizontal stabilizer - the "tail wing" that controls pitch. Yeager eases off the speed & control is regained. He lands and tells Jack Ridley, his flight engineer, that the program is over - he lost control in the transonic region, close to MACH 1.

Ridley contemplates this and says, "You've got a manual trim tab. You think you can manipulate it while going through the transonic region?"