Over shooting waypoints

Can someone explain to me why when you are flying and come up to turns or something the plane doesn’t activate the next leg until it gets right onto the fix and then sometimes overshoots the turn so much.

Or approach mode not starting its turn till it passes the runway and then turns after so then you have to turn back and sometimes get in the way of others on final.

It’s been the most annoying thing ever since I’ve started playing this game and surprisingly no one seems to talk about it. I don’t I usually try counter it myself by going direct to the leg at a specific time to get the turn as close to perfect as possible without overshooting and have to do this weird turn. It’s just really annoying and just curious as to why?

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At the core, IF’s Autopilot roll modes (LNAV and HDG) are not well-tuned for various aircraft performance. Combine that with the 20 deg maximum roll angle, you will need a lot of manual work to anticipate those turns. These have been talked about in one way or another here as feature requests.

Even on straight tracks, a strong crosswind creates very large cross-track errors. A steady crosswind no matter how strong should just result in a simple wind correction angle to achieve the desired ground track. I suspect this is something to do with the closed loop LNAV control law. It can be as simple as adding an integrator to the control law.

I also think the sensitivity is not enough when it comes to tracking radio signals (radials, LOC, and G/S). You need to be very close to the radial you are tracking before the tracking kicks in. This is essentially the overshooting you see when capturing the localizer in APPR mode.

Finally, when it comes to RNAV RNP (which I think is 98% of the case in IF), we need better definitions of the different waypoints and tracks: Is it a fly-over waypoint? Is it a fly-by waypoint? Is this a TF leg? Is this a DF leg? and so on.

To summarize… Improved outer loop control for trajectory tracking, coupled with improved lateral inner-loop control will result in improvement of the problems you are seeing.

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I get it sometimes its annoying i also wish it was better but at the end of the day your supposed to have fun and its good for you iPad / iPhone or samsung (so that it wont die) and its not msfs 🫠 (sorry if i sound mean) thats also the reason why if you make too sharp of a turn your plane just keeps making circles but yeah

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Edited my post above for better clarity.

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Hi, from experience, I would disagree with this:

I have found that the next leg is typically activated before reaching the next fix, as the autopilot attempts to capture the next leg without back-tracking.

Of course, there are some issues with how tight the turn and how close together are the waypoints that cause problems (and wind as mentioned by @polaris-14 not doubt plays some role in this). But this can be true irl as well.

A pilot has to monitor that the autopilot is tracking as expected. It is possible to read elsewhere about airline pilots discussing speed and bank angle limitations (due to high load early in a flight), affecting their ability to make certain irl waypoints (as just one example).

As far as approach, this is most often from not following the recommended procedures for using Appr:

I find that if I follow the tutorial criteria, the vast majority of my approaches using Appr work as expected.

I find it helpful to often go into solo and practice such maneuvers a few times to see what causes something to work vs not work (as in: I still do this fairly regularly).

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Typically I feel like if the waypoints are very tight before lets say, a final approach for example I will automatically have the plane move on to the next leg so that way I don’t overshoot. Or sometimes I’ll just do my own autopilot headings until I’m on base to hit the localizer easier.

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How much you anticipate a turn depends on many things, but at the very minimum would consider groundspeed, curvature (i.e. how much you have to turn), how fast can you turn (namely, maximum bank angle - which is directly correlated with stall), and the kinds of fixes and tracks that you are navigating from and towards (e.g., you cannot anticipate a fly-over fix). A good path planner constantly creates and evaluates trajectories to the next waypoint based on the current state of the aircraft. It’s complex and may not be high on the priority list, but I am looking forward to one day having this capability on a mobile flight simulation :)

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Yes, and my use experience is that the IF AP for the most part works as such. Of course, there are always areas where a system can be improved over time (and we see that according to priority). There are specific cases where there are issues, TBM “bank overshoot” (if my memory is correct).

But for the most part, in my opinion, the negative case is overstated in this topic, so I just wanted to weigh in with an opposing opinion.

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Yeah I do this as well or remove some fixs that are tight together if they really really aren’t necessary