By The CTS Team on December 19, 2017
Category: Aviation Weather

Reporting for Duty: METARs and Aircraft Weather Reports

Avoid Penalties, Train with CTS

In late October, the U.S. Department of Transportation’s Federal Aviation Administration (FAA) proposed a civil penalty of $869,125 against Compass Airlines, LLC. The penalties are being enacted because the airline operated 47 flights where forecasts or reports of adverse weather were not correctly obtained using approved methods. Per 14 CFR Part 135.213, an appropriate weather source shall be from the U.S. National Weather Service, a source approved by the U.S. National Weather Service (such as Flight Service Stations or Automated Weather Observing System), or a source approved by the Administrator (reference OpSpec A010 and FAA Order 8900.1 Volume 3, Chapter 26). To help your operation avoid these costly penalties and risks, here are 3 FAA approved weather reports from approved weather sources and how to read them:

METAR: A METAR is an internationally recognized coded weather report developed from observations of the current surface weather conditions. METARs are generally issued on an hourly basis. A special or SPECI METAR is issued anytime a significant weather change occurs between the routine reports, ensuring all flightcrew be informed of any changing weather conditions. These reports allow pilots to make informed decisions regarding flight safety.

Below is an example and breakdown of a METAR: (as it pertains to the United States).

NOTE: each country is allowed to modify the code. Most changes are moderate, but necessary to accommodate local procedures. For example, international METARs are all in the metric system, but the United States uses the metric system for temperature, dew point, and sea level pressure, and the imperial system to describe wind, cloud layer height, RVR, etc. More information on International METARs can be found in 8900.1 Vol. 3, Chapter 26, Section 2 and the Federal Meteorological Handbook No. 1, Surface Weather Observations and Reports.

PIREP: Although METARs are necessary for gathering surface weather conditions, a pilot weather report or PIREP is essential for providing conditions as they exist in the air, which may not be possible to gather from any other source. ATC gathers PIREPS from pilots when visibility is below five miles or the ceiling is below 5,000 ft, but pilots are encouraged to make a report to an FSS or ATC facility if any unexpected weather conditions occur while in flight. After the report is filed, the information can get to other pilots through inflight advisories.
Below is an example of a PIREP:

For more information on PIREPS and how to decode them, look in Chapter 13 Aviation Weather Services of the Pilot’s Handbook of Aeronautical Knowledge on the FAA website.

AIREP: AIREPs are similar to PIREPs in that they are messages from an aircraft to a ground station. However, they usually include more flight specific information, such as aircraft number or ETA. AIREPs are released on a routine basis and typically are generated from an automated system to be received by a service provider that forwards this information to the NWS. The AWC website provides current AIREPs over the continental United States and portions of the Pacific and Atlantic Oceans.

AIREP example from aviationweather.gov:

Breakdown:

Interested in learning more about aviation weather and weather reports? You can find more in-depth instruction on these topics with CTS’s related indoc training. METAR and TAF, Aviation Weather Theory, AIM, and High Altitude Weather and Aerodynamics all cover weather reports and/or potential weather hazards. To browse our course offerings, including weather preparedness, go to our website or email This email address is being protected from spambots. You need JavaScript enabled to view it.

Related reading:https://www.faa.gov/news/press_releases/news_story.cfm?newsId=22255