 This "pitch up" would result in a rapid increase in angle of attack to approximately 60 degrees, accompanied by lateral and directional oscillation, and followed by sudden uncontrolled yaw and roll.At this point the aircraft would be essentially tumbling, descending at a rate of .To combat this, an automatic pitch control (APC) was added, which initiated corrective action at the proper time to prevent reaching an angle of attack high enough to cause pitch-up under any operating condition.