What FAR 91.175 Actually Governs
FAR 91.175 establishes the operating rules for instrument approaches under Part 91 — specifically, when you may descend below MDA or DA, and what constitutes a legal takeoff and landing in IMC. Every airline interview candidate needs to own this regulation cold. It's not academic; checkairmen ask about it because it directly governs decisions you'll make on the line.
The regulation applies to all civil aircraft operating IFR in the United States. While Part 121 operators layer additional OpSpec requirements on top, the foundation is 91.175. Understanding the base rule makes everything else easier to anchor.
The Three Requirements to Leave MDA or DA
Under 91.175(c), a pilot may not operate below the authorized MDA or continue an approach below DA unless all three of the following conditions are simultaneously met:
- The aircraft is continuously in a position from which a normal landing can be made using normal maneuvers
- The flight visibility is not less than the visibility prescribed for the procedure being used
- At least one of the listed visual references for the intended runway is distinctly visible and identifiable
All three. Not two. This is where pilots get caught in interviews — the visibility requirement and the visual reference requirement are separate and both mandatory. Seeing the approach lights does not mean you've met the flight visibility requirement.
You break out at DA with the runway environment in sight, but your flight visibility appears to be less than the published minimum. Can you continue? No. Flight visibility is a separate, independent requirement under 91.175(c)(1). Both conditions must be met simultaneously.
Visual References: The 10-Item List
Section 91.175(c)(3) enumerates exactly which visual references qualify. One or more of the following must be distinctly visible and identifiable:
- Approach light system (with restrictions — see below)
- Threshold, threshold markings, or threshold lights
- Runway end identifier lights (REIL)
- Visual glideslope indicator (VASI/PAPI)
- Touchdown zone, touchdown zone markings, or touchdown zone lights
- Runway or runway markings
- Runway lights
- Touchdown zone lights
- Approach light system components beyond the 200-foot limitation
- Runway centerline lights
The approach lights alone authorize descent to 100 feet above the touchdown zone elevation, not to landing. To descend below 100 feet AGL, you must have one of the red terminating bars, red side row bars, or the runway environment itself in sight. This nuance appears frequently in oral exams at major carriers.
DA vs. MDA: A Behavioral Difference
DA (Decision Altitude) is a point — you must initiate a missed approach if the requirements of 91.175(c) aren't met at that altitude. MDA is a floor — you may not descend below it, but you can fly level at MDA until the missed approach point if visual references are not yet acquired.
Practically, this means precision and APV approaches (ILS, LPV, GLS) require a timely decision, while non-precision approaches with an MDA give you a brief window to continue at minimums. Many operators restrict this operationally, but the regulatory framework is what 91.175 defines.
At DA on an ILS, you are at a decision point — execute the missed approach or continue. At MDA on a LNAV approach, you may maintain MDA and continue toward the MAP while looking for the required visual references. Once you reach the MAP without them, the missed approach is mandatory.
Takeoff Minimums and Alternate Visibility
91.175 also addresses takeoff minimums for Part 91 operators: there are none specified unless you're departing a Part 97 procedure airport with published takeoff minimums, in which case you must comply. Part 121 and 135 operators face stricter requirements through their OpSpecs, but understanding the Part 91 baseline prevents confusion during transition from GA to airline operations.
Candidates interviewing at regional and major carriers should expect this regulation to come up in systems oral exams and SIC/CA upgrade scenarios alike. Check the United Airlines interview prep and Delta Air Lines interview prep pages for how this topic surfaces in real gouge from recent sessions — sourced from pilots who sat in the seat within the last 90 days.
Preparing for the Oral Exam
Checkairmen aren't looking for a recitation of the regulation. They want to see that you can apply it under pressure — that you understand why the three requirements exist and what happens when one isn't met at a critical phase of flight. Practice articulating the distinction between flight visibility and visual references, explain the approach light limitation without prompting, and connect the regulation to your operator's SOPs.
If you want to stress-test your knowledge before the sim, the AI Voice Coach at Vectors to Hired scores your spoken answers on a 1–5 scale using the same criteria a checkairman applies — including regulatory precision questions like these drawn from 12,800+ operator-specific interview items. Free tier access is available with no credit card required.
Knowing 91.175 at the level this article covers is table stakes. Know it, apply it, and be ready to defend every clause.