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MSL (Mean Sea Level)
A measurement of altitude expressed in feet above the average level of the ocean surface. MSL altitude is used for en route navigation, airspace boundaries, and instrument approach procedures. Altimeters display MSL altitude when set to the local altimeter setting.
Related Terms
- Multi-Engine RatingAn add-on rating to a pilot certificate that authorizes the pilot to fly aircraft with more than one engine. Training focuses on engine-out procedures, Vmc demonstrations, asymmetric thrust management, and multi-engine systems.
- NOTAM (Notice to Air Missions)A notice containing information concerning the establishment, condition, or change in any aeronautical facility, service, procedure, or hazard. Pilots are required to check NOTAMs during preflight planning.
- Part 61Title 14 CFR Part 61 — the FAA regulation governing certification of pilots, flight instructors, and ground instructors. Part 61 training allows flexible scheduling and is the most common path for private pilot students.
- Part 91Title 14 CFR Part 91 — the FAA regulation covering general operating and flight rules for all aircraft operations in U.S. airspace. Part 91 defines rules for VFR/IFR flight, equipment requirements, maintenance responsibilities, and pilot-in-command authority.