Welcome Guest. Sign in or Signup

3 Answers


Asked by: 835 views Flight Instructor, General Aviation, Weather

Non convective sigmet are assigned an alphabetic designator from N through Y (excluding S and T). Why S and T are excluded and whats the purpose of this alphabets?

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

3 Answers

  1. Mark Kolber on Jun 29, 2016

    I’m completely making this up. WAG. Someone who knows will tell us how “educated” my guess is based on simply thinking about it and applying other aviation knowledge…

    The letter designation are used for the same reason ATIS uses letter designators – to differentiate them and their sequence.

    S & T are skipped for the same reason that it stops at Y and doesn’t use Z – to avoid confusion with Airmets S (IFR and obscuration), T (turbulence) and Z (icing)

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes

  2. humble and fly on Jun 30, 2016

    Mark is correct actually.

    To avoid confusion SIGMET can’t be assigned letter of S and T

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes

  3. Mark Kolber on Jul 04, 2016

    Thanks humble. Nice to know that “application” and “correlation” stuff really works!

    0 Votes Thumb up 0 Votes Thumb down 0 Votes

The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.