Part of learning to fly means learning the lingo of aviation. You will have to know many acronyms and abbreviations such as CAVU, VASI, VOR, ILS IMC, VFR, and the list goes on and on. When receiving your preflight weather briefing you should pay particular attention to three of these terms: AIRMETS, SIGMETS and PIREPS (well, NOTAMS are important too, but we’re mainly talking about weather stuff here).
OK! It’s Definition time again:
AIRMET – Airman’s Meteorological Information. Basically, it’s weather information that applies to all aircraft operations, particularly to light airplanes (what most of us use for training). Airmets are issued to warn of hazardous weather not covered in a regular forecast. Weather hazards such as moderate icing, turbulence, winds over 30 knots, ceilings below 1000′ and other bad stuff you really don’t want to fly into.
SIGMET – Significant Meteorological Information. A sigmet is issued whenever hazardous weather may affect ALL aircraft over a specified area. Think of a sigmet as an airmet on steroids. A sigmet will include advisories on severe icing, severe or extreme turbulence, and dust or sandstorms that may reduce in-flight visibilities below 3 miles. A Convective Sigmet is issued for similar hazards, except they are associated with convective activity (generally speaking, that means thunderstorms). A convective sigmet is usually issued when severe thunderstorms, tornadoes, or squall lines are forecast.
PIREP – A Pilot report of actual, in-flight observed conditions. Pireps are especially valuable because the weather guessers on the ground have no other way of verifying their forecast. A pirep can also serve as a warning to other pilots about conditions that may not have been forecast, such as icing or turbulence. That’s something you might want to know before heading in that direction. For more on how you can contribute pireps into the system, check out the Sky Spotter program from AOPA’s Air Safety Foundation.
All of this valuable weather information can be yours for the asking, but you have to know who to ask and where to reach them! When you receive your preflight weather briefing, the briefer should advise you of any adverse weather right off the top. If there are any airmets or sigmets in effect for your route of flight, you will be told about them right away. That can sometimes make your decision for you pretty quickly.
However, what if you are enroute and an airmet is issued or other pilots ahead of you encounter some pretty nasty turbulence? I feel another acronym coming on….EFAS! It’s Enroute Flight Advisory Service, also known as Flight Watch (on a common frequency of 122.0). It is designed to give you updated, pertinent weather information while you are underway.
Here’s yet another acronym for you…HIWAS…Hazardous In-Flight Weather Advisory Service. It contains a summary of aviation weather warnings along with airmets, sigmets, convective sigmets and urgent pireps. You can find HIWAS reports continuously broadcast over select VOR stations.
Remember, your pre-flight weather briefing should be just the beginning of your search for weather information before taking to the skies. You can get continuous weather reports throughout your flight, and you should if there is any doubt whether or not to press onward. My father always told me, “There are safe pilots, and there are dead pilots. Which would you rather be?” Pretty blunt, but it does get the point across.
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