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The Pilots Desk
US-FAA14 CFR 91.177

Minimum altitudes for IFR operations

Read the official rule

In plain English

Except for takeoff/landing, IFR minimum altitudes are the highest of the published minimum (MEA/MOCA) or, where none is published, 1,000 ft above the highest obstacle within 4 NM (2,000 ft in designated mountainous terrain) of your course.

Key points

  • Fly the published MEA (or MOCA within range for nav reception).
  • Off-route: 1,000 ft (2,000 ft mountainous) above obstacles within 4 NM.
  • Always at least the published minimum for the segment.

Common pitfalls

  • Descending below MEA/MOCA where it isn’t authorized.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation.*

This is an original plain-English explanation for training and reference, not legal advice and not for navigation. Always rely on the current official rule linked above. Last reviewed June 8, 2026.