FAA Flight Instructor Airplane (FIA)Weather and Weather ServicesEasy
A flight instructor is explaining the difference between an AIRMET and a SIGMET to a student. Which statement correctly distinguishes the two?
- AAIRMETs are issued only for conditions hazardous to all categories of aircraft, while SIGMETs cover only light aircraft.
- BAIRMETs are issued exclusively for convective activity, while SIGMETs cover only non-convective icing.
- CSIGMETs advise of weather hazardous to all aircraft, such as severe icing, severe turbulence, dust storms, and volcanic ash, while AIRMETs advise of weather primarily hazardous to light aircraft.
- DBoth advisories cover identical hazards and differ only in the issuing agency.
Show answer & explanationAnswer & explanation
Correct answer: C. SIGMETs advise of weather hazardous to all aircraft, such as severe icing, severe turbulence, dust storms, and volcanic ash, while AIRMETs advise of weather primarily hazardous to light aircraft.
SIGMETs warn of weather hazardous to all aircraft (severe icing, severe/extreme turbulence, dust/sandstorms, volcanic ash), while AIRMETs cover conditions of lesser severity that are of significant concern primarily to light or less-capable aircraft, such as moderate icing, moderate turbulence, and sustained winds.
Why the other options are wrong
- A. Reverses the correct scope of each advisory.
- B. Both convective and non-convective hazards can appear in either advisory type (Convective SIGMET is separate).
- D. They are not identical; severity and target audience differ.
AIRMET vs SIGMET
AIRMETs warn of weather hazardous mainly to light aircraft; SIGMETs warn of severe weather hazardous to all aircraft.
- AIRMET Sierra: IFR/mountain obscuration
- AIRMET Tango: turbulence/strong winds
- AIRMET Zulu: icing/freezing level
- SIGMET: severe icing/turbulence, dust storms, volcanic ash
Memory trick: SIGMET is SIGnificant for everyone; AIRMET is for the little AIRcraft.