View Full Version : B737 NG 10.6 FMC upgrade
Eau de Boeing
8th May 2007, 08:42
Can anyone tell me why when you input the speeds into the descent page and begin an LNAV VNAV descent, the commanded speed input from the FMC gives a speed 1kt slower than what you have put in.
I don't think it is part of the whole geometric descent uber-faff that has happened with our company recently but it seems to happen everytime.
Any experts advise?
Cheers
I Just Drive
9th May 2007, 22:01
Ive been wondering that for weeks. It will fly 1kt over or under but never bang on. And we let these things do autolands in fog!
Shaka Zulu
10th May 2007, 10:03
something to do with an auto conversion behind the box from kts to kmh/mps or whatever it does its calculations in and then re converting it back to commands?
when you then manually again put the speed in with descent established it will take the 280kts command for example. its when you leave the box to calculate for itself from T/D it seems to round down 1kt
1 kt?!!!!:ugh:
Having seen the everlasting cock-up it always makes of a descent REGARDLESS of how many 'nudges' you give it on QNH, winds etc, I can readily accept '1 kt':) .