AWC - FAQs

Standardized Text AIRMET FAQs

		Why did the text AIRMET need to be standardized?

		There are three main reasons: 1) to remove ambiguity (more on that later); 2) to make the text more compliant with international standards, and; 3) to allow computer software to create a text AIRMET from and be consistent with AIRMET graphics drawn by AWC’s forecasters.
		We’ve been using text AIRMETs for years. Why should we care about using a graphical AIRMET?

		Actually, aviation weather users have been asking for weather graphics for years. The text AIRMET requires meteorologists to describe hazards over large geographical areas spread over six-hour periods. The graphical AIRMET, or G-AIRMET, promises to provide a decision-making tool based on weather “snapshots” at shorter time intervals. The G-AIRMET will be able to identify hazardous weather in space and time more precisely than text, enabling pilots to maintain higher safety margins while flying efficient routes. G-AIRMETs are a better way for aviation forecasters to show you their forecast through interactive and easy to understand graphical displays. Forecasters will put their energy into creating and updating G-AIRMET depictions. Traditional text AIRMETs will still exist, but will be standardized, derived from and consistent with G-AIRMET information.
		What do you mean by “ambiguity” in the text?

		Some of the terms used in the free-text form of the AIRMET are ill-defined, and could mean different things to different users. One of the goals of the standardization of the text is to have the words mean the same thing to all users.
		If you’re not using “OCNL” or “FRQ” anymore, how do I know what the coverage is?

		According to the AIM (Aeronautical Information Manual), AIRMETs “are issued for ‘widespread’ conditions.” Widespread is defined as affecting or expected to affect an area of at least 3,000 square miles at any one time during the forecast period.
		What does it mean when you say “trend remarks will no longer be included”?

		Statements involving movement of the hazard (i.e. “CONDS SPRDG EWD”) and changes in intensity (i.e. “INTSF” or “WKN”) will no longer be included.
		Why are you not going to include the reason for amending, cancelling, or updating the AIRMET?

		International standards prohibit the inclusion of non-essential descriptive information.
		Why are you removing the cause of turbulence, strong surface winds, and low level wind shear potential?

		International standards prohibit the inclusion of non-essential descriptive information.
		Why are you removing the type of icing?

		The inclusion of icing-type can be misleading. FAA has determined that no icing-type (rime ice, mixed, and glaze or clear) can be excluded from consideration during operations in icing conditions. Therefore, the FAA has stated that it unnecessary to cite the type of icing.
		Why are you removing the location of icing with respect to clouds and precipitation in the ice AIRMET?

		Icing is assumed to occur when an aircraft is exposed to visible moisture (clouds, fog or precipitation). International standards prohibit the inclusion of non-essential descriptive information.

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