FAR 91.169 — IFR Alternate Requirements
FAR 91.169 explains what IFR flight plans must include, the 1-2-3 alternate rule, and alternate airport weather minima. Study guide for pilot students.
FAR 91.169 lists what you must include when filing an IFR flight plan and when you need to file an alternate airport.
Every IFR flight plan must contain the same information required by §91.153(a), plus an alternate airport — unless you qualify for the 1-2-3 rule exemption.
The 1-2-3 Rule (no alternate required) — all must be true:
- The destination has a published Part 97 (or special) instrument approach, and
- From 1 hour before to 1 hour after ETA, forecast ceiling is at least 2,000 feet above airport elevation, and
- Forecast visibility is at least 3 statute miles.
Standard alternate airport weather minima (forecast at ETA at the alternate):
- Precision approach: 600-foot ceiling, 2 SM visibility
- Non-precision approach: 800-foot ceiling, 2 SM visibility
- No approach available: must allow descent from the MEA, approach, and landing under basic VFR
For RNAV approaches with alternate minima, the rule also allows ceiling 200 ft above approach minimum and visibility 1 SM (never less than the approach minimum).
Finally, after activating an IFR flight plan, you must notify ATC or FSS when you cancel or complete the flight — this matters because IFR flight plans don't auto-close, and search and rescue could be launched if you forget.
Five FAA-written-style questions. Instant explanations, every answer cites its source — no account needed.
You are flying VFR in Class E airspace at 8,500 feet MSL during the day. What are your minimum visibility and cloud clearance requirements?