Alternate's route's max altitude not taken into account

SimBrief Dispatch
1

Hello,

I wanted to tell you that the maximum altitude of the route of an alternate airport (for example, closest airport with low airways and low maximum altitude for the airway) is not taken into account by the flight plan calculation.

Regards,

2

Can you please provide a specific example of a destination airport + alternate airport combination where the maximum altitude is not honored (providing the exact routing to the alternate as well)? Sharing the briefing PDF should have all the information we need.

Regards,

Tim

3

EDDFLIML_PDF_1770147791.pdf (714.1 KB)

The route between the destination LIML and the alternate LIPE :

TOVS6J EKPAL M859 LUPOS L995 RIPDU RIPD3W

The maximum flight level for both airways M859 and L995 (low altitudes airways) is FL195, but the simbrief has calculated a flight level of FL270 for the route and for the fuel.

Regards,

4

So I see the intended route was:

TOVS6J.EKP6A EKPAL M859 LUPOS L995 RIPDU RIPD3W

Because you didn’t include the SID transition, the actual planned route was:

TOVS6J TOVSA DCT EKPAL M859 LUPOS L995 RIPDU RIPD3W

It’s possible the initial direct somehow confused Simbrief into planning an altitude above FL195.

Either way, EKPAL M859 LUPOS L995 RIPDU is not a valid route from LIML to LIPE because:

  • the airways require you stay below FL195
  • but the EKPAL 6A transition require that you be at or above FL195 by EKPAL
    (see Jeppesen chart 20-3P if you have a Navigraph Unlimited subscription)

Screenshot 2026-02-06 at 01.15.15
Screenshot 2026-02-06 at 01.15.151600×1660 273 KB

In addition, EKPAL M859 LUPOS L995 RIPDU does not route via TINKU but rule LI2197 says TINKU is mandatory when departing LIME or LIML via EKPAL (unless arriving LIRQ):

Screenshot 2026-02-06 at 01.17.54
Screenshot 2026-02-06 at 01.17.543584×128 20.7 KB

So the automatic altitude being too high is a lesser issue here.

Current real-world routings from LIML to LIPE (also
suitable for use as alternate routings) seem to be:

  • LOGDI DCT RIPDU (no FL195 restriction and seems most common)
    (the direct seems available/valid all the way down to flight level 120)
  • LOGDI T293 LURUT M859 LUPOS L995 RIPDU (FL195- restriction)
    the restriction is honored by Simbrief but this seems to be
    a less common routing with a much higher overhead

Regards,

Tim

5

Thank you for your answer !