Minimum Altitude

Instrument Flight Rules (IFR) Minimum altitudes for Instrument Flight Rules (IFR) operations as prescribed in Federal Aviation Regulation (FAR) Part 91. These altitudes are published on aeronautical charts and prescribed in FAR Part 96 for airways and routes, and in FAR Part 97 for standard instrument approach procedures. If no applicable minimum altitude is prescribed in FAR Part 96 or FAR Part 97, the following minimum IFR altitude applies: 1) In designated mountainous areas, 2,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown; 2) Other than mountainous areas, 1,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown; or 3) As otherwise authorized by the [Federal Aviation Administration (FAA)] Administrator or assigned by Air Traffic Control (ATC). (FAA4)