What is the maximum operating Mach number (Mmo)?

What is the maximum operating Mach number (Mmo)?

• A. 0.75
• B. 0.80
• C. 0.85
• D. 0.90

Answer: (B)

Maximum operating Mach number is the highest Mach at which the airplane is certified to operate in cruise. It’s set to keep enough buffet margin and maintain sufficient control effectiveness at high altitude as air density drops. For many business jets, this limit is about 0.80, so you should not exceed Mach 0.80 in normal cruise. Going beyond MMO can lead to high‑speed buffet, reduced control authority, and potential structural or aerodynamic issues due to swept‑wing shock effects. While some designs may have higher MMO in special configurations, 0.80 is the typical, acceptable cruise limit.

Maximum operating Mach number is the highest Mach at which the airplane is certified to operate in cruise. It’s set to keep enough buffet margin and maintain sufficient control effectiveness at high altitude as air density drops. For many business jets, this limit is about 0.80, so you should not exceed Mach 0.80 in normal cruise. Going beyond MMO can lead to high‑speed buffet, reduced control authority, and potential structural or aerodynamic issues due to swept‑wing shock effects. While some designs may have higher MMO in special configurations, 0.80 is the typical, acceptable cruise limit.