I turned the A/T off and wanted to finish my approach manually. I was in VNAV when I turned the A/T off, but VNAV remained lit and I could not engage SPD. However, if I turned the A/T on, I could engage SPD, and then when I turned A/T off, SPD remained lit as desired. Basically, I wanted to dial in my final approach speed of Vref+5, and I could not do it without the A/T engaged. That does not sound right.Lee Hetherington (KBED)

Lee,Could you rephrase that ? I'm afraid I don't understand...To clear the speed dial blanker, just disengage VNAV or go to another pitch mode... ?anthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com

Hi Lee,The way I have always understand the Boeing AFS philosophy is that "SPD" mode on the MCP is actually an autothrottle mode and not an autopilot F/D mode. All it basically does is adjust the Autothrottles to maintain the speed dialed in on the panel, it doesn't change the pitch to maintain speed like FL CH mode. I am certainly no the FMC expert but I though that the approach numbers on the NG came out of the FMC and would display on the ADI ? Anthony??RegardsPaul Gollnick :-coolTechnical Operations/Customer Operational SupportPrecision Manuals Development Groupwww.precisionmanuals.com

Sorry. That was confusing. Once I turned off the A/T, I could not turn off VNAV. The VNAV light was stuck on when I turned A/T off. The only way I could disable VNAV was to first turn the A/T back on, select a different mode, and then A/T off.I wish I had taken better notes. Here is what I think I did. I was flying an RNAV approach, in VNAV PATH, when I decided to take manual control. CMD off and A/T off, and I was going to fly the FD. Once I turned the A/T off, I could not disengage VNAV to get an MCP speed window so I could set my final approach speed bug. What is the correct procedure in this case?Lee Hetherington (KBED)

Ok got it.Off the top of my head, only when the following conditions are true is the VNAV button inoperative- AP in CWS mode (but this is not implemented yet) - but then selecting AP in CWS would disengage VNAV beforehand- APP is engaged (both GS and LOC) - but then the VNAV select would not be lit... ???Could you shoot a screening of the panel in the situation you describe, with PFD announciators ?But anyway, here's what I'd do in the situation you describe :- disengage all AP modes (CMD off, cycle FDs)- turn on FDs again(BTW those 2 steps are part of a non precision approach on some airlines. Making sure no mode stays engaged...)- switch off AT- arm APPanthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com

In my best Homer Simpson: Doh! I should have just cycled the FDs.I'll try to recreate the situation.Lee Hetherington (KBED)

With the AP out of CMD !;-)anthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com