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757 Captain >> 757 version 4.x (FSX ONLY) >> PERF/VNAV not available msg
https://www.captainsim.org/forum/csf.pl?num=1208022721

Message started by dc9man on Apr 12th, 2008 at 5:52pm

Title: PERF/VNAV not available msg
Post by dc9man on Apr 12th, 2008 at 5:52pm
After takeoff and after engaging the autopilot I select LNAV which works just fine then push the VNAV button and everytime I get a FMC message that says 'PERF/VNAV not available'. What am I doing wrong........................help!!!!!

                   Tom

Title: Re: PERF/VNAV not available msg
Post by signmanbob on Apr 12th, 2008 at 10:08pm
Are you sure you have all of the performance information loaded in the FMC/CDU correctly?  My VNAV works very well.

Title: Re: PERF/VNAV not available msg
Post by w4fej on Apr 13th, 2008 at 12:39am
Are you sure you haven't done something like put a 15000' crossing restriction 2-3 miles after takeoff?  If it can't hack the climb based on the route programmed it will barf on you .

 I have found MANY things wrong in the 757 package but the FMC system isn't one of them.  Programmed properly it works without error.  (so far)

 Mike B.

Title: Re: PERF/VNAV not available msg
Post by dc9man on Apr 13th, 2008 at 5:33pm
Thanks guys for the VNAV tips after being a little more meticulous with perf loading it finally worked for Ol' Tom, I appreciate it.

                Tom :)

Title: Re: PERF/VNAV not available msg
Post by signmanbob on Apr 13th, 2008 at 6:16pm
Glad to hear that you got your problem fixed Tom.

Title: Re: PERF/VNAV not available msg
Post by fowler on Jun 1st, 2024 at 11:46am
I haver the same issue and I have yet to discover where the issue is. I normally enter all required fields in the FMS prior to pushback and it works with the CS 767 all the time (I have never had this PERF/VNAV UNAVIALBLE message) Yet I do the same FMS setup in the CS 757III and I get these messages.

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