AIM Text
- Title 14 CFR specifies the pilot and aircraft equipment requirements for IFR flight. Pilots are reminded that in addition to altitude or flight level requirements, 14 CFR section 91.177 includes a requirement to remain at least 1,000 feet (2,000 feet in designated mountainous terrain) above the highest obstacle within a horizontal distance of 4 nautical miles from the course to be flown.
- IFR Altitudes. (See TBL 3-3-1.)
TBL 3-3-1
IFR Altitudes
Class G AirspaceIf your magnetic course (ground track) is:
And you are below 18,000 feet MSL, fly:
0° to 179°
Odd thousands MSL, (3,000; 5,000; 7,000, etc.)
180° to 359°
Even thousands MSL, (2,000; 4,000; 6,000, etc.)
Source: FAA Aeronautical Information Manual · current edition · paragraph 3-3-3.
The short answer
This AIM section summarizes IFR pilot and aircraft equipment requirements under Title 14 CFR and reminds pilots that 14 CFR section 91.177 requires remaining at least 1,000 feet (2,000 feet in designated mountainous terrain) above the highest obstacle within 4 nautical miles of course. It also restates Class G IFR cruising altitudes by magnetic course below 18,000 feet MSL.
Research Notes
Common Questions
How high above obstacles must I fly under IFR?
What IFR altitudes apply in Class G airspace below 18,000 feet?
Per TBL 3-3-1, for a magnetic course of 0° to 179° below 18,000 feet MSL, fly odd thousands MSL (3,000; 5,000; 7,000). For 180° to 359°, fly even thousands MSL (2,000; 4,000; 6,000).
What governs the equipment I need for IFR flight?
The AIM states Title 14 CFR specifies the pilot and aircraft equipment requirements for IFR flight. This section is advisory guidance pointing to those regulations rather than the rule itself.