FAA Aircraft Dispatcher (ADX)MeteorologyMedium
A dispatcher reviewing current advisories sees an active AIRMET Sierra for the route of flight. What hazard does this advisory primarily indicate?
- ASevere turbulence associated with thunderstorms
- BIFR conditions and/or extensive mountain obscuration
- CSevere icing conditions
- DWidespread duststorms reducing visibility below 3 miles
Show answer & explanationAnswer & explanation
Correct answer: B. IFR conditions and/or extensive mountain obscuration
AIRMET Sierra (IFR) advises of instrument flight rules conditions and/or extensive mountain obscuration affecting a significant portion of the route. AIRMET Tango covers turbulence and strong surface winds, and AIRMET Zulu covers icing and freezing levels; severe conditions of these types are covered by SIGMETs instead.
Why the other options are wrong
- A. Severe turbulence from thunderstorms is addressed by Convective SIGMETs, not AIRMET Sierra.
- C. Icing conditions, when moderate, are covered by AIRMET Zulu, not Sierra.
- D. Widespread duststorms with visibility below 3 miles are addressed by SIGMETs, not AIRMETs.
AIRMET Categories
AIRMETs (Airmen's Meteorological Information) advise of weather hazards significant to light aircraft that are less severe than those covered in SIGMETs, issued in three categories: Sierra, Tango, and Zulu.
- AIRMET Sierra: IFR conditions and mountain obscuration
- AIRMET Tango: moderate turbulence and sustained surface winds ≥30 knots
- AIRMET Zulu: moderate icing and freezing levels
Memory trick: 'Sierra=Sight (IFR/mountains), Tango=Turbulence/wind, Zulu=frost/icing (freeZing).'