What is the maximum Mach number?

What is the maximum Mach number?

• A. 0.79
• B. 0.84
• C. 0.88
• D. 0.82

Answer: (B)

The question is testing your understanding of what the maximum Mach number represents. Mach number is the ratio of true airspeed to the local speed of sound, so it changes with altitude and air temperature. The maximum Mach number is the highest speed at which the aircraft is certified to fly in cruise without risking buffet, loss of control, or structural overstress. For this aircraft, the published limit is about 0.84 Mach, which defines the upper boundary you should not exceed during cruise. Speeds well below that are fine, while speeds above the limit push past the design and certification limits and can lead to aerodynamic/structural problems. That’s why the value around 0.84 Mach is the best match for the maximum Mach number.

The question is testing your understanding of what the maximum Mach number represents. Mach number is the ratio of true airspeed to the local speed of sound, so it changes with altitude and air temperature. The maximum Mach number is the highest speed at which the aircraft is certified to fly in cruise without risking buffet, loss of control, or structural overstress. For this aircraft, the published limit is about 0.84 Mach, which defines the upper boundary you should not exceed during cruise. Speeds well below that are fine, while speeds above the limit push past the design and certification limits and can lead to aerodynamic/structural problems. That’s why the value around 0.84 Mach is the best match for the maximum Mach number.