Good day all.

 

A week ago I noticed that I cannot engage the autopilot. Before departure I arm VNAV and LNAV and before takeoff roll I increase thrust to 40% N1 and hit TOGA, at that moment both VNAV and LNAV disengage for some reason (it never happened before). I am able to re-engage them again on takeoff roll or after lift off but autopilot won't engage whatever I try. I have to hand flying all the way.

I use FS2crew as well, not sure if there is any relation between this issue and FS2crew. I cannot figure out what am I doing wrong or what causing the problem.

Thank you.

If you have Realistic Autopilot Engagement enabled, the aircraft has to be in trim with minimum control surface deflection, attitude near the FD command, and elevator trim not moving, for CMD to engage.

If you have Realistic Autopilot Engagement enabled, the aircraft has to be in trim with minimum control surface deflection, attitude near the FD command, and elevator trim not moving, for CMD to engage.

 

Thank you for the reply. I know it and I have Realistic A/P engagement. I had not problem with that before. I stabilize the airplane well before A/P engagement and it always worked. Something happened recently and A/P is dead. I am also wondering why after pushing TOGA button VNAV and LNAV kicks off.

Something happened recently and A/P is dead

 

Try to check failures page.

 

I am also wondering why after pushing TOGA button VNAV and LNAV kicks off.

 

It's normal that LNAV/VNAV lamps go off when pressing TO/GA. Despite this they leave armed, LNAV engages at 50', VNAV - at 400' RA.

I just ran the flight again. LNAV and VNAV lamps went if and then turned on again on takeoff. But autopilot did not engage whatever I tried. Failures are off. :(

Just a thought

Check your assignment axis and reset them, or reassign them and mostly important use FSX axis instead of FSUIPC.

FSUIPC and FSX file calibration can degrade and NGX is really sensitive in this regards.

Are you trying to engage the autopilot through FS2Crew, i.e. through voice or by clicking the CMD button yourself? I have a problem with FS2Crew, where I don't think I have ever managed to get FS2Crew to turn it on although the copilot does confirm my command. It works manually though by clicking, so if that doesn't work for you, then the issue must be different.

Not sure about the VNAV and LNAV going off though, as I tend to only turn them on in the air.

Just a thought

Check your assignment axis and reset them, or reassign them and mostly important use FSX axis instead of FSUIPC.

FSUIPC and FSX file calibration can degrade and NGX is really sensitive in this regards.

 

Well, I use FSUIPC for controls and rudder pedals only and my throttles is assigned through FSX.

Will check. Thank you.

 

Are you trying to engage the autopilot through FS2Crew, i.e. through voice or by clicking the CMD button yourself? I have a problem with FS2Crew, where I don't think I have ever managed to get FS2Crew to turn it on although the copilot does confirm my command. It works manually though by clicking, so if that doesn't work for you, then the issue must be different.

Not sure about the VNAV and LNAV going off though, as I tend to only turn them on in the air.

 

Neither way worked. I had submitted ticket and I was suggested to re-install NGX and I did. A/P works now, but...my Autothrust won't hold anymore. I have to keep pushing the button till it sticks. What a day. One problem was fixed and another came on.

Thanks guys.

Just a thought

Check your assignment axis and reset them, or reassign them and mostly important use FSX axis instead of FSUIPC.

FSUIPC and FSX file calibration can degrade and NGX is really sensitive in this regards.

 

I think you were right. A/P did not work on my British Airways livery only. I ckecked other liveries and it did work well. I found that this airplane with BAW livery is the only assigned and calibrated via FSUIPC and it causing the problem. I will recheck again tonight but I think that FSUIPC is an issue.

Thx