APPR Rework/Improvements

Introduction

Autoland/approach mode (APPR) is the system we have in Infinite Flight on some aircraft that automatically lands the aircraft without control inputs from the pilot. It’s great for landing in conditions with low visibility, such as nighttime or fog. Many pilots also use APPR because of its ease and convenience for landing.

The Problems

Rough Landings

One problem the APPR system has is its rough landings. With the current APPR system, an aircraft flares a few seconds too late, usually resulting in a -400 fpm touchdown, which is a considerably rough landing. Real life autoland systems can land just as softly as a pilot, if not softer. Two examples of a rough APPR landing are shown below, but simulated in windless conditions. The final landing vertical speed was approximately -421 fpm. You can clearly see the roughness with which the aircraft lands. While the aircraft used was a CRJ, this phenomenon is consistent with every other APPR-equipped aircraft in Infinite Flight

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Violent Jerking and Overcorrections

The second problem the APPR system has is the violent jerking of the aircraft caused by the system attempting to intercept the glideslope/localizer, even with the aircraft perfectly aligned. When APPR is engaged, it will immediately force the aircraft in an extreme vector to intercept the glideslope/localizer. Then, because of the violence of the input, the aircraft will overcorrect, effectively causing another violent jerk. Below is an example of both phenomena. You can clearly see that the aircraft is almost perfectly aligned with the glideslope and localizer, so there is no reason for the excessive jerking. It should also be noted that, as a result of the violent jerk, the aircraft missed the glideslope completely.

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Conclusion

As Infinite Flight continues to rework and develop new aircraft, it is important that the APPR system is correctly programmed. Hopefully, this request will bring around the change that is needed, and persuade the developers to take another look at their current systems. I believe that it’s important to do something right the first time, so hopefully the developers will change this before future updates, rather than having to go back to fix the system post-release. I’d like to hear the community’s thoughts on this!

Done and done. Voted.

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In complete agreement this could use a lot of additional optimization. You have my vote.

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This is important than others reworks, even though I don’t use APPR

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Is there any videos showing a real life example of an autopilot landing? Just wondering what exact differences would this make.

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Nice and Detailed Thread!

I do agree that the developers could have a look at this rework for the possible future as if you have your hands busy during final approach it is very difficult for the aircraft not to be violent.

Now I need to free up a vote

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There are plenty, but most are from the cockpit view, where you can’t really tell a difference. The idea is that, if you were planespotting from the ground and you saw a B737 coming in for landing (for example), you wouldn’t be able to tell if it was the pilot landing or the autoland system, because the autoland can grease just as good as the pilot can. (In real life)

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Search on YT: CAT III Landing

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Hi!

This is a good video of a CAT III Autoland. You can see the plane write out the phase of the approach on the top left of the PFD, as well as the nice flare just before touchdown and be sure watch the V/S decrease as well. https://www.youtube.com/watch?v=i1joEc-vKsk

–Jakub

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this is very important in my opinion. voted

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I never use APPR-because of the violent yanking and banking it does-even when I’m at a ~30° intercept and a dot low on the glideslope it still for some reason yanks and banks me-even after watching the tutorials I still can’t quite figure out how to get it right. For example I was practicing approaches in 1SM visibility yesterday at KBOS-I wound up having to use what I call the “RNAV coupled approach” (which basically means having the waypoints for ILS in my FPL and putting altitudes from the Approach charts into In Flight Assistant) and disconnecting at minimums-But if it was Cat IIIb-we technically need to use APPR (but if we had a flight Director on the HUD-it would be like jetBlue and American who have zero/zero handflown approaches on the E190/737 respectively due to the HUD)

As far as the VS on landing-Autolandings are notably more firm than an actual pilot-the job of the computer is to get the thing onto the runway.
I’m not as concerned about the VS as I am a smoother intercept.

Gonna look to free up a vote for this.

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I agree! Sometimes I have to turn APPR off as I can see it ending badly…

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Yeah, there have been times where I almost stalled because of the APPR’s harsh control inputs. I’ve even seen complaints here about people that have gotten violations because of the flawed system.

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You’ve got my vote, this has been an issue for a long time. Another thing I would add is to turn off the “steering” at touchdown. I don’t use APPR very often, but when I do, the plane seems intent on drifting off the runway. If the plane would just free up the yoke at touchdown, it would be easy to just use the rudder slider as normal, and not end up needing massive over corrections to stay on the runway.

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i never used APPR, i have recently did a flight to Narita in which there was fog at low altitude during approach but thankfully it wasn’t CAT I level so i manually flied the aircraft as soon as i entered the fog,. but yeah i hope they fix it, not just APPR but autopilot in general,.

i just wish pilots not use APPR casually, i hope they only use it when its really needed, for realism purposes but yeah this is just a sim so if you wanna casually do APPR landings feel free to do so, i just encourage more realistic flying,.

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Amazing request!

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Yeah I agree. While I don’t use APPR often, some situations (such as low vis) require it, and I’d like to know that there is a system in place that I can count on!

Great video I love Guillame’s channel! Notice that the landing VS is between 300/200 during the flare! Auto lands are noticeably more firm than manual landings. (And after checking the virtualBlue messages, I of course started surfing the community forgetting to logout of the VA acct 🤦‍♂️)

Yes indeed it is very bad when coming to first engagement. For the time being I recommend to calibrate right before engaging APPR.

Sometimes though, even after calibrating it gets worse. 1 time I engaged APPR, it did a SUPER VIOLENT jerk and the aircraft went into a free fall and crashed into the mountain near Kai Tak Airport (which was my destination).

Great thread. I agree with you about the improvements. Voted.

1 Like