Do you fill in the cruise speed and level in the Route Manager?
I don't touch the cruise speed, I believe the default is 320 kts so I leave as is but I enter the cruising altitude.
Could you describe all the specific steps you do regarding the autopilot up to moment it happens? E.g. what do you enter in the RM, what modifications do you do to the flight plan, what AP modes do you use... We should be able to find out what you do differently than me that avoids me from reproducing this bug.
Before taxi I look at takeoff ref, so I manually dial in the ref speed + approx 5% IAS, next step I enable L & R A/T, FD on, next step I dial my VS to about + 1500, I don't enable VNAV, this way I control the amount of thrust via my throttle.
Note; the reason I do it this way is if I take off heavy, lets say from EDDF to KJFK (or further) I can control the amount of thrust and reach my cruising altitude sooner. ( I know in real life this is probably not recommended to avoid over thrust).
I fly manually (because I like to and for practice) up to about 1/2 way of the cruising altitude, then I enable LNAV, enable A/T, then AP mode if I'm lined up on my route and my VS is in line with the FD indicator, then enable FLCH,
finally but not always I'll enable VNAV, and of course QNH to standard when over FL 180.
what modifications do you do to the flight plan,
When landing at KLAX west bound the charts have 7 or 8 waypoints you need to enter, (using Skyvector.com) but sometimes the RM will select the default STAR and this conflicts with the waypoints from Skyvector so I remove some of the default waypoints so that everything is westbound. And that should be it!!!!
Again, I've done these steps now for almost a year without an issue until now on FG 2019.1.1.
AAL4955