Hello All, I cannot get any of the Vertical modes to work. My bird climbs through selected altitudes, does not hold selected vertical speeds, VNAV does not work and computed VNAV airspeeds are not held. Lateral Nav modes all work well. What am I doing wrong?Regards,Stephen Shallcross

Does AutoThrottle arm and remain on?Are there any disconnect errors in the route?Did you see the PREFLT CMPLT when setting up FMC?

Steven, also when you arm and engage the autothrottle doe you get the N1 indication? I have had a problem in the past that when I engage the autothottle the V-Speeds are deleted, not allowing me to have autothrottle engaged. Ensure that on the Takeoff Page the V-Speeds are in bold font and that the V-Speeds are on your airspeed tape. Do you have the correct flap setting on takeoff? Have you changed runways or changed the fuel since programming the FMC? These are all possible reasons for the problem you are experiencing.

Stephen if you can post a screen shot of a typical problem. A picture says a thousand words sort of thing. Give a brief description of what you were trying to achieve.CheersSteve

Hello,Yes it does. When annunciation is VNAV SPD when climbing, speed will be held as VNAV SPD suggests. However when levelling off and annunciation goes to VNAV PTH, speed is not held. The THR and SPD buttons do not have a yellow light on and you can't turn them on. Should SPD appear in the left column of the annunciation when in VNAV PTH because it isn't!Thanks,Stephen

Hi Dan, When you say N1 indication, are you talking about the top of the tapes on the EICAS display? I do have those. I also have V-Speeds evident on the speed tape. Speed is held during VNAV SPD but not when levelling off and going to VNAV PTH or when using V/S. Should a SPD annunciation appear on the left column of the annunciation panel. It doesn't at present.Regards,Stephen

I have question to ask all of you folks in line with this threadon my 737 i constantly have the issue of the auto -throttle flipping of.Typicaly i fly as follows , fms programmed, ap engaged, fd engaged , lnav engaged just off the runway,to/ga on rollout,I find that quite often when i engage the ap ,fd and try to fly the athrottle will not engage , it just flips off. ? does anyone understand this,the little annunciator light also comes on in the small three light annunciation warning light panel??I must have some setting in the fms incorrect?Peter Kofman

Stephen when you press TO/GA on takeoff do the A/T's set takeoff thrust and indicate THR or THR REF then HOLD when rolling down the runway?Seems to me like your A/Ts are not engaging for some reason.Once again a screen shot would help.CheersSteve