V1.32 VNAV issues...

[airfrance]

Hello,

I'm on 1.32 and I keep having issues arming the VNAV. I can't ever get it to arm on the ground so therefore when I go into TO/GA mode, I'm not getting the correct thrust for the climb profile and I'm not getting the magenta lines on the PFD from the F/D. Only after I lift off and I get positive rate am I able to arm VNAV (and LNAV for sake of argument. Can't arm LNAV on the ground either.). When I engage the A/P, VNAV immediately disengages and I get a CWS amber light under the CMD green on the PFD. It immediately will go into CWS mode for pitch. I have to keep pressing VNAV over and over and it will finally engage. What is going on? 

For example sake, I needed TO/GA thrust for take off which was 91.7%. I hit the TO/GA button (with VNAV/LNAV disengaged but they never would engage on the ground) and only got about 87% N1. Once I lifted off and hit VNAV and LNAV, the thrust went up to 91.7% where it was supposed to be. I find myself pulling back too hard because I don't have F/D help on takeoff.

Edited August 14, 2020 by airfrance
Added example

[airfrance]

Okay so I understand now that you can't arm the LNAV and VNAV on the ground as the classic uses the older A/P than the NG. Activating the proper TO/GA mode will engage a pitch and roll mode and then you can engage LNAV and VNAV after takeoff. My issue is I can't ever arm VNAV. Not sure if it's a noisy yoke axis or what. It takes forever and I often have to keep clicking it over and over before it will finally engage.

[Litjan]

Hi airfrance,

yes, that is a common misconception, you are right, on the "classics" you can´t arm LNAV and VNAV on the ground. You will use the TO/GA mode and once airborne you can select LNAV (above 50 feet) and VNAV will usually be selected at the acceleration altitude (1000 or 1500 feet AGL).

The problem getting VNAV to "stick" is usually due to input from the joystick - we have a "deadzone" slider in the preferences menu that will allow you to make your joystick less "sensitive" to the autopilot. Try increasing this zone and see how it goes?

Cheers, Jan

Edit: It is the 4th point in this post:

 

Edited August 15, 2020 by Litjan