Definition
A specific section of the U.S. federal aviation regulations, located in Title 14 of the Code of Federal Regulations, Part 91, Appendix D, Section 3. This section lists the airports at which fixed-wing special VFR (visual flight rules) operations are prohibited. It is referenced in helicopter VFR minimums because helicopters are generally not subject to these same restrictions, which is one of the operational differences pilots must understand when comparing fixed-wing and helicopter VFR rules.
Plain English
A particular paragraph in the federal aviation rulebook that names the airports where airplanes are not allowed to use special VFR. Helicopters are usually not held to this same list, which is why the rule gets mentioned in helicopter VFR sections.
Context Anchor
Seen in FAA handbook discussions of helicopter VFR minimums and special VFR operations near controlled airports.
Derivation
CFR stands for Code of Federal Regulations, the official compilation of U.S. government rules. Title 14 covers Aeronautics and Space. Part 91 covers general operating and flight rules. An appendix is an attached section at the end of a Part, and § is the standard symbol for section. So the citation reads as a precise address: book, part, appendix, section.
Why Pilots Care
Helicopter pilots must meet these minimums to stay legal and avoid enforcement action when operating in the affected areas.
Intuition Check
Do not read this as a weather minimum by itself. It is a legal pointer to a list of airports and restrictions that affects whether certain special VFR operations are allowed.
Example Sentence 1
Before filing for special VFR into that Class B airport, the pilot checked 14 CFR Part 91, appendix D, § 3 to confirm fixed-wing special VFR was not prohibited there.
Example Sentence 2
During preflight planning the instructor pointed out that 14 CFR Part 91, appendix D, § 3 governs helicopter VFR operations near the listed airports.