Definition
A section of the Federal Aviation Regulations that establishes the rules for using Enhanced Flight Vision Systems (EFVS) during instrument approaches. It permits pilots to descend below the published Decision Altitude, Decision Height, or Minimum Descent Altitude using EFVS imagery in place of natural vision, and in some cases to continue all the way to landing using EFVS, provided specific aircraft equipment, pilot training, currency, and operational requirements are met.
Plain English
This is the rule that says when and how a pilot is allowed to use a special infrared or enhanced-vision display to fly an instrument approach lower than would normally be allowed -- and in some cases all the way down to the runway -- without seeing the runway with the naked eye.
Context Anchor
Seen in instrument approach and missed approach discussions, especially when deciding whether enhanced flight vision can be used below normal approach minimums.
Derivation
CFR stands for Code of Federal Regulations. Part 91 is the section covering general operating and flight rules for civil aircraft. The number 91.176 simply identifies this specific rule within Part 91. The number itself has no meaning beyond being the regulation's address.
Why Pilots Care
Pilots must comply to maintain legal IFR operations and decide correctly whether to continue to landing or execute a missed approach.
Analogy
A regulation citation works like a street address. “14 CFR Part 91 § 91.176” tells you exactly where to find this particular rule in the federal aviation regulations.
Intuition Check
Do not read 14 CFR Part 91 § 91.176 as an approach procedure or a minimum altitude by itself. It is a regulation that tells you when a specific kind of enhanced-vision operation is allowed.
Example Sentence 1
The crew briefed the EFVS approach in accordance with 14 CFR Part 91 § 91.176, confirming both pilots were current and the required visual references would be identified before continuing below DA.
Example Sentence 2
When the runway environment could not be identified in time, the crew initiated the missed approach as required by 14 CFR Part 91 § 91.176.