LNAV circling at faster simulation speeds

[tarunmarella]

Hello...
Flying a long haul route in a 777-300ER
At a normal simulation speed (x1), the Autopilot works just about fine, going exactly in the set route.
But at a rate of say, x16 and 32x, the LNAV goes haywire by turning circles left and right , until I return to the default simulation speed and let the plane return to the set route.
It’s a bit irritating, especially on long haul flights.
Currently, I just HOLD the heading and then after 10-15 mins (when I’m way out of path) , I click LNAV, let the plane return to the set route and then click HOLD again...
I would be really grateful to anyone of you for helping me with this
Thanks for considering this question!

[wkitty42]

the thing is that advancing the simulation speed means that the calculations are not done at that faster speed... this means that at 16x, you're skipping (eg) 15 of the calculation rounds so the craft has moved further than expected/desired... when the next round is calculated, the craft sees that it has flow passed where it needs to be so it turns to get back on track...

the solution is to not run the simulator at high simulation speeds... OR rewrite the autopilot to work properly at high simulation speeds...

[Isaak]

the solution is to not run the simulator at high simulation speeds... OR rewrite the autopilot to work properly at high simulation speeds...

... and as far as I know, that requires changes in the core that are certainly not on the short-term todo-list of people developing the 777. So the current solution is either doing shorter flights, or letting the sim run at lower sim speeds. In my experience, letting it run on 8x works fine most of the time, just avoid short route legs in your route (delete waypoints to make sure there are no <20 mile legs and avoid sharp curves in the enroute part of the route). Since you seem to not mind very much about realism, you can also choose to fly the SID, add no route and fly direct to the entry waypoint of the STAR. You'll have fewest flaws like that

[tarunmarella]

the solution is to not run the simulator at high simulation speeds... OR rewrite the autopilot to work properly at high simulation speeds...

... and as far as I know, that requires changes in the core that are certainly not on the short-term todo-list of people developing the 777. So the current solution is either doing shorter flights, or letting the sim run at lower sim speeds. In my experience, letting it run on 8x works fine most of the time, just avoid short route legs in your route (delete waypoints to make sure there are no <20 mile legs and avoid sharp curves in the enroute part of the route). Since you seem to not mind very much about realism, you can also choose to fly the SID, add no route and fly direct to the entry waypoint of the STAR. You'll have fewest flaws like that

My route manager consists of the departure waypoints, the main leg of the route, and the approach waypoints. But still the LNAV doesn't follow that one straight route till the destination airport (atleast until I can take control of it myself, starting with descent).
But anyways, thanks to Isaak and wkitty42 for clarifying this doubt of mine... Hope you're safe!