Dauntless Aviation
 
FAA Written Test Prep
Checkride Oral Exam Prep
Pilot eLogbook System
Aircraft Systems Reviews
EASA Theory Exam Prep
China ATPL Theory Prep
UK PPL/IMC Theory Prep
Transport Canada Theory Exam Prep
Aircraft Recognition Tutor
SimPlates IFR Plates
FAR/AIM Reference
All Software and Apps
Aviation Freebies
Free Aircraft Checklists
 
Products by Platform
 
Purchase
Support
Contact
Employment
SBD Dauntless
 
Affiliates and Resellers
 
Europe/Worldwide FAA CFI Services
 
淘宝商城
 
Home

Aviation Glossary :: Flight Level  Aviation Glossary :: Flight Level FAA Written Test Preparation
Aviation Glossary Welcome to the Dauntless Aviation Glossary!

At Dauntless, our editorial staff maintains the web's largest unified glossary of aviation terms. This glossary is built from a combination of official, quasi-official, and proprietary sources (including original material that we develop oursselves). Uniquely, we often provide multiple definitions of a given term so that you can find that which best applies to you. In order to maximize your learning efficiency, this glossary (and similar ones for our international users) is incresingly fully integrated into our aviation learning apps, including our FAA written test prep and FAA practical test prep software and apps. If you like this glossary, you'll love them with their polished learning environments and world's best and clearest content (please do give them a try.).

Flight Level
Flight Level
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—flight level 250 represents a barometric altimeter indication of 25,000', flight level 255 as 25,500'.
Report an issue with this definition

source: FAA Aerosense Glossary

Flight level means 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 250 represents a barometric altimeter indication of 25,000 feet; flight level 255, an indication of 25,500 feet.
Report an issue with this definition

source: FAA Federal Aviation Regulations (CFR 14 Part 1)

A flight level is a level of constant atmospheric pressure related to a reference datum of 29.92 "Hg. Each flight level is stated in three digits that represents hundreds of feet. For example, FL 250 represents an altimeter indication of 25,000 feet.
Report an issue with this definition

source: FAA Instrument Procedures Handbook (FAA-H-8083-16)

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.

A surface of constant atmospheric pressure which is related to a specific pressure datum, 1013.2 hPa (1013.2 mb), and is separated from other such surfaces by specific pressure intervals.

  • Note 1: A pressure type altimeter calibrated in accordance with the standard atmosphere:
    1. When set to a QNH altimeter setting, will indicate altitude;
    2. When set to a QFE altimeter setting, will indicate height above the QFE reference datum; and
    3. When set to a pressure of 1013.2 hPa (1013.2 mb), may be used to indicate flight levels.
  • Note 2: The terms `height' and `altitude,' used in Note 1 above, indicate altimetric rather than geometric heights and altitudes.

Report an issue with this definition

source: FAA Pilot/Controller Glossary

A measure of altitude (in hundreds of feet) used by aircraft flying above 18,000 feet with the altimeter set at 29.92" Hg.
Report an issue with this definition

source: FAA Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25A)

A measure of altitude (in hundreds of feet) used by aircraft flying above 18,000 feet with the altimeter set at 29.92 "Hg.
Report an issue with this definition

source: FAA Risk Management Handbook (FAA-H-8083-2)

A surface of constant atmospheric pressure which is related to a specific pressure datum, 1013.2 hectopascals (hPa), and is separated from other such surfaces by specific pressure intervals.
Report an issue with this definition

source: FAA/NOAA Aviation Weather Services (AC 00-45G)

A flight level (FL) is specific barometric pressure, expressed as a nominal altitude in hundreds of feet. The pressure is computed assuming an International standard sea-level pressure datum of 1013.25 hPa (29.92 inHg), and therefore is not necessarily the same as the aircraft's true altitude either above mean sea level or above ground level.

Historically, altitude has been measured using a pressure altimeter, which is essentially a calibrated barometer. An altimeter measures air pressure, which decreases with increasing altitude following the barometric formula, and from the surrounding's pressure calculates and displays the corresponding altitude.

To display altitude above sea level, a pilot must recalibrate the altimeter according to the local air pressure at sea level, to take into account natural variation of pressure over time and in different regions. If this is not done, two aircraft could be flying at the same altitude even though their altimeters appear to show that they are at considerably different altitudes.

Flight levels solve this problem by defining altitudes based on a standard air pressure at sea-level. All aircraft operating on flight levels calibrate to this setting regardless of the actual sea level pressure.

Flight levels are described by a number, which is this nominal altitude ("pressure altitude") in feet, divided by 100, while being a multiple of 500 ft, therefore always ending on 0 or 5. Therefore an apparent altitude of, for example, 32,000 feet is referred to as "flight level 320". To avoid collisions between two aircraft due to their being at the same altitude, their "real" altitudes (compared to ground level, for example) are not important; it is the difference in altitudes that determines whether they might collide. This difference can be determined from the air pressure at each craft and does not require knowledge of the local air pressure on the ground.

Flight levels are usually designated in writing as FLxxx, where xxx is a one- to three-digit number indicating the pressure altitude in units of 100 feet. In radio communications, FL290 would be pronounced as "flight level two niner zero", in most jurisdictions. In some states, levels ending with 00 are read as "hundred": FL200 is pronounced as "flight level two hundred". The phrase "flight level" makes it clear that this refers to the standardized pressure altitude.

Report an issue with this definition

source: Wikitionary / Wikipedia and Related Sources (Edited)


Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

Disclaimer: While this glossary in most cases is likely to be highly accurate and useful, sometimes, for any number of editorial, transcription, technical, and other reasons, it might not be. Additionally, as somtimes you may have found yourself brought to this page through an automated term matching system, you may find definitions here that do not match the cotext or application in which you saw the original term. Please use your good judgement when using this resource.


© 2019 Dauntless Aviation • 4950C York Road 110, Buckingham, PA, 18912, USA • Contact UsPrivacy Policy