Plain English Meaning

FL 350 means the aircraft is flying at 35,000 feet on the altimeter, with the altimeter set to a standard pressure setting that all aircraft use up there. It is the level used during cruise on most airline flights.

Full Definition

FL 350 is a specific flight level corresponding to an indicated altitude of 35,000 feet when the altimeter is set to the standard pressure of 29.92 inches of mercury (1013.2 hPa). Flight levels are used at and above 18,000 feet MSL in the United States, where all aircraft set their altimeters to the same standard pressure so that vertical separation is maintained relative to a common reference rather than to local sea-level pressure.

Context Anchor

Seen in - , descriptions, and for aircraft operating in the flight levels.