Hiya amigos,

okay this might be a silly question and maybe i'm an word not allowed but:

Orlando. The wind was from the right, so the aircraft was compensating on approach. but then on landing the autopilot did not disconnect, and also ignored all my inputs to the left -> i ended up eating dirt

 

Now in the 737

Tampa, one hour later. The landing was against the wind indicated, but actually the wind was all over the place. a/p disconnected before touchdown, the end result was much better though.

would a real 787 behave as in the first video? should I have disconnected the a/p manually? why didn't it disconnect automatically if the conditions were beyond its capacity?

forgive my ignorance 🙂

Edited October 10, 20241 yr by SimianFlu

Let's discuss these separately.

First landing (787)

The crosswind limit for an autoland on the 787 is 25 knots, I believe. Looking at the wind arrow, this looks to have been right at the limit, or maybe slightly above it.

It looks to me as if the autoland implementation here simply isn't quite as capable as on the real aircraft. It doesn't seem to make any real attempt to eliminate the crab before touchdown, and also obviously doesn't prevent the aircraft from going off the centreline.

I think the best thing to do here would have been to disconnect the autopilot once you noticed it was deviating from the centreline on rollout.

2 hours ago, SimianFlu said:

would a real 787 behave as in the first video?

My expectation is that it would handle the crosswind better.

2 hours ago, SimianFlu said:

should I have disconnected the a/p manually?

Yes.

2 hours ago, SimianFlu said:

why didn't it disconnect automatically if the conditions were beyond its capacity?

I'm not very familiar with the 787, but I don't think there's any expectation that the autopilot will disconnect by itself in this situation,

Second landing (737)

This was a 60-knot headwind. I haven't looked up the limits for the 737, but I'm pretty sure this would be well beyond the limit for an autoland.

All of this is academic, though, because the aircraft wasn't correctly set up for an autoland anyway. Both autopilots need to be engaged for an autoland (here's a tutorial), but the "SINGLE CH" annunciation in the video means that only one autopilot was connected. With a SINGLE CH approach, you need to disconnect the autopilot at the CAT I DH at the latest (typically 200 feet above the runwax). If you don't do this, I believe on the 737 it disconnects automatically at 100 feet radalt, which seems to be exactly what happened here. Just before this, the autopilot was already getting to some pretty large bank angles this close to the ground, which would probably have been a cue to disconnect the autopilot yourself. Not sure why it did this because it looked as if it was perfectly on the localizer.

Note that when the autopilot disconnects by itself, you would typically press the autopilot disconnect button to silence the "wailer" that alerts you to the disconnect.

After the autopilot disconnect, the aircraft deviates above the glidepath and ends up landing well beyond the touchdown zone. Again, the best action here would have been to go around.

Hope this helps!

Edited October 10, 20241 yr by martinboehme

Sure it does help! thanks a lot mate 🙂 and. thanks for the double channel tutorial, actually I did try to engage CMD2 but it disconnected CMD1 after a while and stayed single on CMD2. Never have landed in such conditions before so never needed full ILS III 

UPDATE - i watched the video and I was doing everything as explained. Except for setting course, thought that was only required with VOR.

Edited October 10, 20241 yr by SimianFlu

I think the best thing to do would be to avoid trying to land in a hurricane

6 hours ago, SimianFlu said:

why didn't it disconnect automatically if the conditions were beyond its capacity?

An ap automatically disconnecting you on final approach at or below minimums could very likely kill you! The manuals recommend/insist you disconnect at certain wind strengths but you as pilot get the final choice. Same with windshear. You need disconnect ap and at ASAP and apply manual thrust but the plane won't do it for you. (from a recent perusal of fcom). 

1 hour ago, Christopher Low said:

I think the best thing to do would be to avoid trying to land in a hurricane

That would be my plan too, divert to Atlanta

What is interesting to note here is that the flight path vector symbol has run out of screen space and his hard left against the speed tape. In these situations in the so called “real world” we’d select declutter mode on the HUD it gives the FPV more lateral room.

I can’t remember if the WT HUD has declutter mode, not flown it for a while, I wouldn’t be surprised if it did, they’ve done a nice job.

 

The real 787 autopilot would engage a cross controlled wing down technique on that approach, IE an into wind sideslip, oh and I think the FAA limit autolands to 15kt crosswind so you’re busted !😉

4 hours ago, jon b said:

What is interesting to note here is that the flight path vector symbol has run out of screen space and his hard left against the speed tape. In these situations in the so called “real world” we’d select declutter mode on the HUD it gives the FPV more lateral room.

I can’t remember if the WT HUD has declutter mode, not flown it for a while, I wouldn’t be surprised if it did, they’ve done a nice job.

 

The real 787 autopilot would engage a cross controlled wing down technique on that approach, IE an into wind sideslip, oh and I think the FAA limit autolands to 15kt crosswind so you’re busted !😉

somebody's gonna give me a number to call ig 🙂 woahh the real 787 is quite a beast then 😃 FAA limits aside, how much crosswind the AP would handle?

Edited October 10, 20241 yr by SimianFlu

6 hours ago, sloppysmusic said:

An ap automatically disconnecting you on final approach at or below minimums could very likely kill you! The manuals recommend/insist you disconnect at certain wind strengths but you as pilot get the final choice. Same with windshear. You need disconnect ap and at ASAP and apply manual thrust but the plane won't do it for you. (from a recent perusal of fcom). 

Makes sense. Still, the 737 ap disconnected 40ft above minimum, does it make it sort of a homicidal maniac? ^_^

25 minutes ago, SimianFlu said:

Makes sense. Still, the 737 ap disconnected 40ft above minimum, does it make it sort of a homicidal maniac? ^_^

As far as I could tell, it disconnected at 100 feet AGL - that's 100 feet below the CAT I decision altitude.

48 minutes ago, SimianFlu said:

Still, the 737 ap disconnected 40ft above minimum, does it make it sort of a homicidal maniac?

I'm fairly certain that you are simply exceeding the limits of the autopilot in those conditions. Hand fly it or go to your alternate.

2 hours ago, SimianFlu said:

woahh the real 787 is quite a beast then

Speaking as an ex 747 pilot …….No !😏

 

2 hours ago, SimianFlu said:

FAA limits aside, how much crosswind the AP would handle?

It’s a 25kt limit for everywhere else, although I wouldn’t like to do a cat3 in a 25kt crosswind personally, I’m getting too old for that sort of stuff 😂

The real problem in the 737 example is that you weren't even flying an ILS, let alone an auto land.  Look at the flight mode annunciators - you're in FAC / GP instead of LOC/GS.  You're effectively flying an RNAV approach using the IAN mode modeled in the PMDG (but which most real operators do not use as it's less capable than LNAV/VNAV.). You can accidentally end up in this mode if you arm approach too far out, before you're receiving the ILS.

In both aircraft, AIII mode would be used in the HUD for anything below cat I.

The 787 exited the runway upwind because of MSFS 's poor crosswind and ground physics.  It understands the airplane should weathervane into the wind, but not that it should be BLOWN downwind.  The effect is also greatly exaggerated, so you'll lose control of an airplane in much lighter wind than you would in reality.

39 minutes ago, Stearmandriver said:

The real problem in the 737 example is that you weren't even flying an ILS, let alone an auto land.  Look at the flight mode annunciators - you're in FAC / GP instead of LOC/GS.

Oooooh -- completely missed this when I watched the video. This would also explain why the autopilot disconnects at 100 feet AGL -- IIUC this is exactly what the autopilot logic is supposed to do on an IAN approach?

10 minutes ago, martinboehme said:

Oooooh -- completely missed this when I watched the video. This would also explain why the autopilot disconnects at 100 feet AGL -- IIUC this is exactly what the autopilot logic is supposed to do on an IAN approach?

https://www.flaps2approach.com/journal/2015/1/4/integrated-approach-navigation-ian-review-and-procedures.html

A nice big read tnere but you'll come out the other side enlightened! 

If you want to fly fairly realistically set your minimums at MDA (use the mcp to set that altitude so ap will level off before you dive into darkness ). If you see the runway keep going, switch to manual, if you don't go around or divert. The ap will fly you right into the ground if you want it to but please don't let it lol 🙏😎