bug: in cruise, switching to VOR/LOC changed FMC to descent mode

[Guest ilh]

I was flying KSFO PORTE3.AVE.SADDE6 KLAX, and 80+nm from AVE in cruise at FL330, I pushed VOR/LOC to track the R-117 into AVE. I was previously in LNAV. The moment I pushed VOR/LOC, I got an FMC message that I hadn't selected my approach VREF. Hmmm. At that point I noticed T/D was gone and that it was clearly in DES mode, with PROG page giving me E/D instead of T/D. Map mode on the ND shows the VNAV deviation scale.I am quite sure that should not have happened. Certainly I should be able to use VOR/LOC to track raw data in cruise without starting descent mode.EDIT: Meanwhile, the DES page is showing a bogus V/B of 3.1 when I am 172nm from my SYMON 12000 constraint, while I'm at FL330.Help, Anthony!Lee Hetherington (KBED)

[Guest ilh]

More wierdness during the flight. VNAV was non-functional, so I did the descent with V/S to hit my constraints. T/D was still on the ND even though not on the FMC PROG page. However, as soon as I reduced MCP altitude at 5nm (no FMC message prompting me to do so), descent began, and the VNAV deviation scale went up to at least 10000. At some point it disappeared.Bummer. My first flight with SU 1.1 and VNAV flaked out, but it was likely due to using VOR/LOC in cruise. Oh well. Otherwise, the flight went fine.Lee Hetherington (KBED)

[crvm 0]

Lee, FYI, it's no different than the other one if you get my drift ;)[h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-8/196432/winglets_lg.jpg [h3] AMD XP 2200 |MUNCHKIN 512 DDR RAM |ECS[/b ][i] K7S5A MB[/i] |GF2 MX 32 MEG and still runs GOOD!|WIN XP PRO |MITSUBISHI DIAMOND PLUS 91 19"[/h3]

[Guest tmetzinger]

>I am quite sure that should not have happened. Certainly I>should be able to use VOR/LOC to track raw data in cruise>without starting descent mode.>If you're only interested in tracking the raw data, I would think the way to do that would be:Leave the autopilot in LNAV/VNAVMake sure the VOR is tuned on nav 1 or nav 2Turn on the VOR1 or VOR 2 pointers on the display, OR change the display (not the autopilot) to VOR.That way, the FMC plan is still flying the airplane horizontally and vertically, but you are checking to see that you're on the appropriate radial.-Tim Metzinger

[Guest ilh]

Yes, I was doing just that, all through the PORTE3.AVE. Being the curious type, I like to push things :-) and I was curious what would happen if I switched lateral mode to VOR.It certainly isn't a show stopper. I was just pointing out that changing a lateral mode shouldn't kill the vertical mode in this case.Something for the fix list.Lee Hetherington (KBED)

[Guest neil_c]

An interesting one, and most likely related to something else I found a while ago. If you want to fly around completely manually, the selected Vref never appears on the speed tape.But guess what? Engage VORLOC mode alone and bingo, Vref appears! :-lolThe Vref bug should appear immediately upon selecting a Vref from the FMC.

[crvm 0]

The Vref bug should appear immediately upon selecting a Vref from the FMC. Yep, that's what the AOM states too.[h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-8/196432/winglets_lg.jpg [h3] AMD XP 2200 |MUNCHKIN 512 DDR RAM |ECS[/b ][i] K7S5A MB[/i] |GF2 MX 32 MEG and still runs GOOD!|WIN XP PRO |MITSUBISHI DIAMOND PLUS 91 19"[/h3]

[Guest amerton]

Hi all,Tracking an ILS was the way to force landing phase if it is required.The problem is that I was too generous and did not filter on an ILS nav.I corrected this in the code.ThanksanthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com

[Guest tmetzinger]

>Hi all,>>Tracking an ILS was the way to force landing phase if it is>required.>The problem is that I was too generous and did not filter on>an ILS nav.>I corrected this in the code.>Thanks>>anthony>>Anthony Merton>Precision Manuals Development>http://www.precisionmanuals.comI assume the fix is NOT in SU1.1, as this problem still exists, but will be in SU2?

[Guest amerton]

Definitely in SU2.It was just addind 2 "words" in a line of code...Small causes... big effects...cheers,anthonyAnthony MertonPrecision Manuals Developmenthttp://www.precisionmanuals.com