Have the same problem - thought it was me but perhaps not.To add to the above.1. Pre - TO. Select LNAV on MCP - it arms {white on FMA}2. Post TO. LNAV engages correctly {green on FMA} but LNAV light on MCP extinguishes.3. Climb/Cruise. LNAV remains engaged {green on FMA} and follows correct route - LNAV MCP light remains out4. At any stage - press LNAV on MCP: LNAV disengages and AP reverts to CWSR5. Press LNAV again and LNAV re-engages and reverts to normal operation.As with the OP could not find this in FCOM or tuuorial so perhaps some of our experts could advise as they do not see it- is it something in my NGX set up?John Rooum

I'm also having this exact same behaviour on the LNAV light on the MCP extinguishing, even though the AC is flying in LNAV mode. I uninstalled the original basepack, then reinstalled base-pack and SP1 as recommended. I did not observe this pre SP1. BTW, have not actually tried the -800 after installing expansion, so I don't know if this is related to the -700

I have the same problem, I noticed, thought it didn't bother me much, that if I engaged both VNAV and LNAV on the ground, that sometimes after I press TOGA, LNAV would extinguish.I would usually repress the button after takeoff, before I engage AP, but that would sometimes disengage VNAV (as I remember!). In the end, a click here and there would solve the "situation".But: sometimes it all went normal, 2 are on, two are kept on, and I only press AP.The situation I was testing was a saved flight from EGKK to LOWI, always the same config, and I always take care that I have right configuration on takeoff, along with correct trim and following the FD anyway possible, usually between 15 and 20 degree up. With the exactly same procedure, sometimes it happens and sometimes not. Maybe I am missing something, but I think not.

That is correct behaviour !!Both LNAV and VNAV will extinguish until airborne.That said, they both should light up again !!! Fred.

Just to put my tuppence worth inI do not and repeat do not have this behaviour. I can put VNAV and LNAV on on runway press TOGA and they stay onThx Ian

Same problem here, after SP1

I wanted to mention that I have the same problem with LNAV MCP button remaining extinguished after takeoff with SP1. I sure hope PMDG notices, has someone here submitted a ticket on the PMDG website?

That is correct behaviour !!Both LNAV and VNAV will extinguish until airborne.That said, they both should light up again !!! Fred.

I know it's normal that lnav and vnav extinguish. I maybe wrote it a bit clumsy.They should relight, and they don't. Sometimes they do, but mostly only vnav, lnav light keeps being off.About the mode being active still, that I would have to check. Back home end of the week...

I know it's normal that lnav and vnav extinguish. I maybe wrote it a bit clumsy.They should relight, and they don't. Sometimes they do, but mostly only vnav, lnav light keeps being off.About the mode being active still, that I would have to check. Back home end of the week...

Hmm, haven´t noticed this, maybe I haven´t discovered that cause I´m always engage LNAV when passing some 400 RA. Before that I´m usually sets the Roll mode to heading, when lined up./ Leffe

Anyone opened a ticket for this?

same problem here too

The only answer seemed to be a re-install. So, followed the PMDG advice on this forum to the letter - including restoring to before I installed the NGX and rebuilding FSX.cfg etc etc. Did not delete any reg items - I had no problems activating anyway in the first place.Then after following the Introduction file, i re-installed and loaded and followed the tutorial flight {which uses the Collins MCP} to the letter.Result was:1. VNAV /LNAV armed correctly with lights on pre-TO.2. On selecting TOGA, VNAV and LNAV lights extinguished {ok for Honeywell but Collins …?} both modes remained armed.3. Initial climb out, LNAV and VNAV engaged correctly but only VNAV illuminated - LNAV light remained out throughout climb and cruise.4. Sometime during approach when manoevering to LOC, LNAV illuminated again and I could carry out a full LAND 3 autoland - ie Collins MCP operating correctly.I then flew a second sector using the Honeywell MCP - VNAV/LNAV LIGHTS reacted correctly throughout.So far with no comment from PMDG and no one posting to confirm that they see the correct and exact behaviour, still not sure whether this is an installation problem or bug ………………….?John Rooum

This is a bug (I said this in different thread on the issue) - fixed for SP1B (no ETA on release).

Great !!Thanks Ryan.Fred.

Thank you for clearing that up Ryan!Devin Mack