Definition
The federal regulation governing instrument approach procedures and the conditions under which a pilot may descend below the published Decision Altitude (DA), Decision Height (DH), or Minimum Descent Altitude (MDA) on an instrument approach. It specifies the visibility requirements, required flight visibility, and the visual references the pilot must have in sight before continuing the approach to landing. It also contains the rules permitting descent below DA/DH/MDA when using an Enhanced Flight Vision System (EFVS).
Plain English
This is the FAA rule that tells a pilot exactly what they need to see, and how clearly they need to see it, before they are allowed to keep descending and land from an instrument approach. It also includes the special rules for using enhanced vision equipment to do this.
Context Anchor
Seen in discussions of Enhanced Flight Vision Systems, where the handbook points to the regulation that controls how EFVS may be used during an instrument approach and landing.
Derivation
‘14 CFR’ means Title 14 of the Code of Federal Regulations, which is the part of U.S. federal law covering aeronautics and space. ‘Part 91’ is the section of those rules covering general operating and flight rules for civil aircraft. ‘Section 91.175’ is the specific numbered rule within Part 91. Knowing the structure helps because pilots will see regulations cited this way throughout their training and career.
Why Pilots Care
It determines whether a pilot using EFVS can legally continue an approach below standard minima, directly affecting whether a landing is possible in low-visibility conditions.
Analogy
Think of the citation like a street address for a rule. “14 CFR” is the city, “part 91” is the neighborhood, and “section 91.175” is the exact building you need.
Intuition Check
Do not read “part” and “section” as casual book divisions here. In this context, they are exact legal locations inside the federal aviation regulations.
Example Sentence 1
Before descending below the Decision Altitude, the pilot confirmed the visual references required by 14 CFR part 91 section 91.175 were in sight.
Example Sentence 2
Compliance with 14 CFR part 91 section 91.175 is required whenever an approved Enhanced Flight Vision System is used to continue an approach in reduced visibility.