Definition
A specific section of Title 14 of the Code of Federal Regulations, Part 23, that establishes the minimum control speed requirements for small airplanes certificated in the normal, utility, acrobatic, and commuter categories. Section 23.149 defines minimum control speed (VMC) and the conditions under which it must be determined, including the airplane's ability to maintain straight flight with one engine inoperative under specified configurations.
Plain English
This is the rule in the federal regulations that says how slow a small multi-engine airplane can be flown after losing an engine while still keeping the airplane controllable. It sets the standard that manufacturers must meet to publish a minimum control speed for the airplane.
Context Anchor
Seen in FAA handbook definitions and training discussions that refer to the legal source behind minimum control speed.
Derivation
CFR stands for Code of Federal Regulations. Title 14 covers Aeronautics and Space, and Part 23 covers airworthiness standards for smaller airplanes. The section number 23.149 simply identifies one specific paragraph within Part 23. The numbering is a filing system, not a meaningful name.
Why Pilots Care
V_MC is a critical limitation that directly affects safe takeoff, climb, and go-around decisions after an engine failure.
Analogy
A regulation citation works like a street address. “14 CFR part 23, section 23.149” tells you exactly where to find one rule inside a large body of federal aviation rules.
Intuition Check
Do not read “part” here as an airplane component. In a regulation citation, “part” means a numbered group of rules, and “section” means the exact numbered rule within that group.
Example Sentence 1
The published VMC for this light twin was determined in accordance with 14 CFR part 23, section 23.149.
Example Sentence 2
During certification testing the manufacturer must show compliance with 14 CFR part 23, section 23.149 at the most critical weight and center of gravity.