FLIGHT LEVEL

Definition

• A level of constant atmospheric pressure related to a reference datum of 29.92 inches of mercury. Each is stated in three digits that represent hundreds of feet. For example, flight level (FL) 250 represents a barometric altimeter indication of 25,000 feet; FL 255, an indication of 25,500 feet. (See ICAO term FLIGHT LEVEL.)

References

• Pilot Controller Glossary, Federal Aviation Administration, 2023