Definition
A section of Title 14 of the Code of Federal Regulations, Part 91 (General Operating and Flight Rules), that establishes the performance and equipment requirements for Automatic Dependent Surveillance-Broadcast (ADS-B) Out systems installed in aircraft. It specifies the technical standards the equipment must meet, the data the aircraft must transmit (such as position, altitude, velocity, and identification), and the integrity and accuracy thresholds the system must achieve.
Plain English
It is the federal rule that says what an aircraft's ADS-B Out equipment must be able to do and what information it must broadcast.
Context Anchor
Seen when studying ADS-B Out requirements for controlled airspace, including Class A airspace in the United States.
Derivation
CFR stands for Code of Federal Regulations -- the official collection of U.S. federal rules. Title 14 covers Aeronautics and Space, Part 91 covers general flight rules, and section 91.227 is the specific paragraph dealing with ADS-B Out performance standards. The numbering tells you exactly where in the rulebook to look.
Why Pilots Care
Failure to meet these standards prevents legal flight in Class A, Class B, Class C, and certain other airspace.
Analogy
Think of the citation like an address for a rule: Title 14 is the neighborhood, part 91 is the street, and section 91.227 is the exact house.
Grounding Statement
When you see 14 CFR part 91, section 91.227, think: the rule that says the aircraft’s ADS-B Out equipment must be accurate and properly set up.
Intuition Check
Do not read “part 91” as an aircraft part or a page number. In this citation, “part” and “section” are locations inside the federal aviation rules.
Example Sentence 1
Before the avionics shop signed off the installation, they verified the transponder met the performance requirements of 14 CFR part 91, section 91.227.
Example Sentence 2
The examiner asked whether the installed transponder satisfied 14 CFR part 91, section 91.227 performance criteria.