Sst??
 

It started as idle curiousity and has developed into near obsession! What does SST mean when used in the context of SIGMETs?? Answers please....(and no it's nothing to do with the Hounslow hotdog)

SuperSonic Track. They're things which affect Concorde operations, which includes stuff at higher than normal aircraft operating altitudes and also turbulence forecasts which fall below the normal reporting threshold for conventional aircraft but which could affect supersonic ops. Or something like that.

MWOs are responsible for the preparation and dissemination of SIGMETS to appropriate ACC/FIC within their own and agreed adjacent FIRs. Aircraft in flight should be warned by the ACC/FIC of the occurrence or expected occurence of one or more of the following SIGMET phenomena for the route ahead for up to 500nm or 2hrs flying time:


(b) At transonic and supersonic cruising levels (see Note3) (SIGMET SST)
- moderate or severe turbulence;
- cumulo-nimbus cloud;
- hail;
- volcaninc ash cloud

Note 3: FL 250-FL 600 within London and Scottish UIRs, FL 400-FL600 within Shanwick OCA.

So as far as i can tell it's more to do with levels thans speeds

Yeah, I've heard the supersonic track explanation before, but why then do you sometimes see the term on the milan sigmet for example pertaining to FL390 and below. Firstly there are no supersonic tracks in milan FIR, secondly almost all pax jets can reach FL390, and higher, so surely a general sigmet would be issued for all traffic at those levels. Thanks for the replies though, guys, I'm going for a lie down.:confused: