On 7/31/2023 at 10:48 AM, Bob Scott said:

I see no mention of temp dev from ISA in this discussion...that might explain some things.

Check the OAT, which is displayed on one of the screens.  In the past, some addons have caused very high air temperatures at high altitudes, which can seriously affect performance.  Also, in the current heat wave, some mid-level altitude temperatures are (realistically) unusually high.

9 hours ago, Lidan said:

I’m changing me the temp according to simbrif 

Sounds like you got it sorted, good news!  

Just one more caution about simbrief though - you want to remember that it's pretty simplistic as flight planning software.  It's great for us simmers for sure, but unlike real dispatch software it doesn't actually know much about the performance capabilities of various aircraft in various conditions.

So you can use the altitude simbrief gives you as a starting point, but you need to use your own tools in the cockpit (ie look at optimum altitude on the cruise page) to ultimately figure out if you can get there or not.  👍

5 minutes ago, Stearmandriver said:

Of course, I always do it but I think simbrif give me a High coast index Always around 60 What is the normal cost index