Critical Mach Number(Mcrit)
Definition
The Mach number at which airflow over some part of the aircraft first reaches the speed of sound. Beyond this speed, shock waves form causing drag rise, buffeting, and potential loss of control.
Why Critical Mach Number Matters for Pilots
Understanding Critical Mach Number is critical for passing the FAA Private Pilot Knowledge Test and performing safely in flight. Aerodynamics questions make up a significant portion of both written exams and oral checkrides. Pilots who grasp concepts like Critical Mach Number can make better decisions during all phases of flight, from takeoff to landing.
Exam Tip
This concept is commonly tested in aerodynamics-related questions on FAA and EASA exams. Make sure you can explain Critical Mach Number in your own words for the oral exam. Practice applying this concept to real-world scenarios, not just memorizing the definition.
Related Terms
Share this with a fellow pilot
Related Content
Situational Awareness
Aviation glossary definition and exam tips.
Stress Management
Aviation glossary definition and exam tips.
See And Avoid
Aviation glossary definition and exam tips.
ATPL Theory Complete Guide
Master every subject covered in airline pilot exams.
Free Practice Exam
Test your aviation knowledge with real exam questions.
Built by a commercial pilot
Pass your written for $39 — every track, 60 days
Critical Mach Number is one of 5,500+ exam topics in the All-5 Bundle: PPL / IR / CPL / ATPL / Part 107 / TAE. One-time payment, no subscription. Free 30-day extension if you fail your real exam.
Test your knowledge
Think you understand Critical Mach Number? Challenge yourself with practice questions covering aerodynamics and all other exam subjects.
Try Free Practice QuestionsMore Aerodynamics Terms
Angle of Attack(AoA)
The angle between the chord line of an airfoil and the relative wind. As AoA inc...
Lift
The aerodynamic force perpendicular to the relative wind generated by an airfoil...
Drag
The aerodynamic force opposing the motion of an aircraft through the air. Drag h...
Parasite Drag
Drag not associated with lift production, including form drag from the aircraft ...
Would you pass the real exam right now?
Take a free practice quiz — real FAA-style questions, instant score. No signup to start.
Take the free quiz →