Unusual step blimbs and descents on Y100

Hi guys!

I observed for a long time now that when filing a route departing from EDDM via Y100 UMTEX DCT TRA […] the dispatching system is usually planning an initial RFL = F240 followed by a step descent UMTEX/F230 and some step climb later on at TRA.

IRL, these level changes become necessary as soon as the Flight Buffering Zones around TRA Allgäu (ED-R1/2/3/407) become active, which is only the case when the area is actually booked. However a FPL with initial RFL and a step climb at UMTEX would be valid already as it is clear of the FBZ some miles prior to UMTEX. Example: N0360F240 MERSI Y100 UMTEX/N0420F390 DCT TRA […].

Is it intended that Simbrief actually checks for the activation times for the FBZ and therefore adds those level changes? Asking because I wasn’t able yet to force the system creating a FPL without lvl changes outside the activation times (without disabling the stepclimb option ofc).

If simbrief does not respect those FBZ for it’s planning, there seems to be something odd with the configuration of the airway regarding mandatory levels as the airway exists up to FL660.

Looking forward to hearing from you about this, even if just to understand the calculations simbrief is doing there.

Best regards,

Hi JV,

In the routes editor, you can override these altitudes for your submitted route by entering 24500/UMTEX/99999 into the Altitude Restrictions option:

SimBrief cannot check activation times, so in general it’s better to submit routes and altitude restrictions assuming that the areas are active, to maximize the chances that a route will always be valid on a given day.

As an aside, I think the step down to FL230 at UMTEX is due to a coding error in the AIRAC data. The AIRAC specifies odd altitudes when flying from UMTEX to TRA, whereas the AIP says that odd altitudes only begin at the next segment from TRA to WIL. Will investigate further with our data provider.

Best regards,

Great! Thans for the quick answer :slight_smile:

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