Mach tuck is a condition experienced by an aircraft in a transonic flight, exclusively when it accelerates upon reaching the critical Mach number. Accelerating beyond this limit results in the shock waves over the wings to get stronger and move aft. The center of pressure Cp moves aft as well, along with the lift component. This induces a pitch down moment caused by the couple, center of pressure and center of gravity, on the aircraft. If the downwash velocity decreases, this would also contribute to the pitch down moment. The result is that the nose pitches down and the aircraft goes into an extreme dive.
Frequently Asked Questions
Is it possible to recover from Mach tuck?
Recovering from a Mach tuck is almost impossible, as the shockwaves would obstruct the airflow to the elevators. With insufficient air, elevators would not be able to pitch the nose up again.