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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 12^th, 2008 at 5:52pm

Title: PERF/VNAV not available msg
Post by dc9man on Apr 12^th, 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 12^th, 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 13^th, 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 13^th, 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 13^th, 2008 at 6:16pm

Glad to hear that you got your problem fixed Tom.