Which of the following is a potential consequence when accelerating through the critical Mach number?

• A. Increased Cruising Altitude Capability
• B. Decreased Airframe Wear
• C. Control Difficulties
• D. Reduced Fuel Consumption

Answer: (C)

As you push through the critical Mach number, airflow over the wing becomes compressible and shock waves form. These shocks change the pressure distribution, causing lift and drag to shift suddenly. More importantly for handling, the flow can separate around control surfaces, reducing their effectiveness and producing buffet. That combination makes piloting more difficult, with stick forces and response becoming less predictable.

Other options don’t fit because cruising altitude capability is set by engine and airframe design, not simply breaking Mcrit; airframe wear doesn't decrease just from reaching transonic speeds and can even increase from buffet loads; and fuel consumption typically does not drop in this regime—wave drag generally increases, making transonic flight less fuel-efficient.