Why does the FMC tell me “unable 8000 at sunst “ ? When I programmed the flight plan correctly ?

Question

Hi again

I programmed a flight plan from KSFO to KLAS using the correct SID and STAR and correct waypoints

but am told by the FMC “ Unable 8000 at sunst” which is a waypoint close to Las Vegas. Cruising altitude

is 30000. I even tried reprogramming it again with a lower altitude of 15000 feet and still received the same

error message. Please tell me what I am doing wrong so I can correct this error message and program the

correct flight plan that the FMC will say is okay.

Thanks a lot,

John

Answer 1

Hi John, Thanks for your question! What aircraft are you using here? Thank you!

Comments

Hi

The default 737-800

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Hi

I reprogrammed the flight at 20000 feet and the error message was gone and all the waypoints had speed snd altitudes set. Strange because a flight from San Francisco to Las Vegas can easily fly at or above 30000 feet with plenty of time for the decent to make those altitudes at Las Vegas. Probably a little glitch with the FMS

Just wanted you to know

John

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Hi John, Okay, thanks for the report! I will look into this. Thanks, Thomson