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Autoland update 184


Camille MOUCHEL

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Marcel Semelka

Now have a look at that, I gave it another try, same Airport, same Runway (EDDT, ILS RWY26R).

This time I chose a DH of 50ft and the Autoland was smooth like butter... I mean like melted butter almost :D

-9 fpm according to projectFLY :D

Is that normal behaviour or a bug ? Looks more like a bug to me, doesn't it ?
MDA = no flare at Autoland, at least it loooks like it.

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That's not correct, however. The limitation on autopilot engagement in the FCOM is MDA for a non-precision approach, or 1

Hi guys, As you may know, i have concerns regarding the current flare mode of the bus, so I decided to check the Autoland and I think that there is a flaw too. Indeed, the bus barely flared and smas

So my test was for what? For you to say i am wrong. Thats me out of this convo.

Hi guys,

Did an autoland today at KFLL, ILS 28, slowly retarded throttle at the 50' RA callout, and the flight logging program I was using, bluCARS, recorded a -65 FPM.

"[13:40] - Landed at -65fpm. With 847gal of fuel onboard and a pitch angle of 3deg."

I can't do that hand flying my landings, mine are always -200 to -300 fpm.

Jim

 

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Antonis Kastrinakis

If I am not mistaken CAT IIIb LVPs are not very common due to the strict requirements of the ILS system, at the airfields that support it, to be functioning fault-free for an insane number of hours. CAT IIIa ops are slightly less demanding but not by a huge amount. I will try to find that source and post it here. Then again, I am just an armchair jockey so my understanding may very well be skewed. I do, however, think that in the case of zero vis minima the prudent course of action would be to divert to one's alternate.

Not quite the source I was looking for but pertinent to the topic anyway :). Have a look.

https://www.youtube.com/watch?v=Q8-jw48X6nY

 

Edited by Alpha_floor
Link added.
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Arto E.P. Karhu
10 hours ago, Simon Kelsey said:

The main issue is that when the weather is good the ILS signal is not protected to the same standard as required for CAT II and III operations. Unlike during normal CAT I ops where only the ILS critical areas need be protected, for CAT II and III ops the much larger localizer/GP sensitive areas have to be protected. This is, amongst other things, what LVPs (Low Visibility Procedures) are designed for, and essentially it means that departing aircraft have to be held further away from the runway when holding short and landing aircraft need to be completely clear of the localizer sensitive area before the next aircraft can pass a particular point (usually the FAF). As you can imagine, this means big gaps between arriving aircraft, and even bigger gaps if you need to depart aircraft in between arrivals, which is why the landing rate goes down the pan when the visibility drops.

This also means that airports are generally reluctant to implement LVPs unless they have to (because the reduced flow rate causes chaos). If LVPs are not in force, the ILS sensitive areas will not be protected and therefore an aircraft on approach may experience undesirable signal fluctuations. This is why autolanding off a CAT I approach without LVPs in force should be done with extreme caution -- there's fairly dramatic video on Youtube of a Singapore B777 going grass-cutting at Munich as a result of a CAT I autoland -- an aircraft departing ahead overflew the localizer array and distorted the beam, resulting in the landing and rollout going very wrong.

An added nuisance is, on some airports, that some runways are effectively unused because taxi routes to them would cross the runway to which CAT approaches are being performed - a situation that is typically wanted to be avoided. This further reduces the capacity.

Indeed what is obviously totally missing in FSX/P3D is that how sensitive the ILS is to various error sources. A big reason for this is that the antennas are never perfectly directional in a way that would be optimal to the system depending of that. Side beams are inevitably produced, and actual patterns can be rather complicated outside the main beam. The actual, resulting radiating pattern is extremely sensitive of the environment: an object placed suitably can, for instance, reflect energy from some side beam into the general direction of the main beam. By the very way ILS functions, it is extremely sensitive to this kind of effect. In one instance at certain airport, just as an example, when a new hangar was built to an apron some distance away from the nearest runway, it was soon noticed that opening/closing of the hangar doors caused issues with localizer signal. Eventually, the localizer antenna was 'adjusted', I understand by adding some elements to redistribute that specific side beam elsewhere.

-Esa

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Camille MOUCHEL

Thanks for the video. Tu i still don't understand why you would need to set a MDA or DH for an autoland otherwise you have to land manually.

Plus we can the see the aileron moving but not the elevator and yet you still managed to get a greaser.... it's weird as I'm wondering what made the plane pitch up during flare. We will need to wait for the devs inputs


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Simon Kelsey
Thanks for the video. Tu i still don't understand why you would need to set a MDA or DH for an autoland otherwise you have to land manually.


Because, as discussed above, autolanding is not just a case of pressing the button, sitting back and waiting for the aeroplane to land itself.

There has to be a DH in some cases because you have to be able to confirm the system is operating correctly. The law doesn't talk about autoland, it talks about categories of approach -- autoland is just a means to an end because it would be impossibly challenging for an average human pilot to consistently transition to manual/visual flight and land at these low DHs.

As you go from CAT IIIb to CAT I there is progressively less redundancy and protection built in to the system. For example, the requirements in the event of an autopilot failure are different from CAT IIIb No DH to CAT IIIa (50ft DH). If you have a failure below the alert height on a CAT IIIb approach, it should not affect the aircraft's ability to autoland successfully because the system must be fail-operational. However, you can perform a CAT IIIa approach with a fail-passive autopilot system -- but you need to have at least the minimum specified visual references (one light) in order to confirm that the aircraft is actually over the threshold and the system is operating as expected. And so it goes on as you go up to CAT II.

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Camille MOUCHEL
11 hours ago, Simon Kelsey said:

Only for a CAT IIIb approach (and even then some companies and/or countries do not permit no DH ops -- France for one certainly always used to require a nominal DH, though this may have changed).

CAT IIIa approaches have a minimum DH of 50ft, and CAT II approaches have a minimum DH of 100ft. An autoland is SOP off of all three, however (at least at BA, and I don't imagine other companies would be significantly different). Even for no DH, I would probably still enter 0 in the minimums field.

Always radio minimums for CAT II/III ops as the law (SERA) requires it (do check the approach plate as the exact radio DH will naturally depend on the terrain along the approach path and at the relevant MAPt). CAT I approaches, however, are always baro minima (in this particular version of the FMGS, using the MDA box).

how could you perform an autroland if you have a DH of 50fts, that means that no autoland is allowed and that pilot as to take disengage AP before 50 fts

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Simon Kelsey
4 minutes ago, Cmbaviator said:

how could you perform an autroland if you have a DH of 50fts, that means that no autoland is allowed and that pilot as to take disengage AP before 50 fts

Why do you say that?

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Simon Kelsey
1 minute ago, Cmbaviator said:

for me if there is a DH, you can't autoland

That's not correct, however.

The limitation on autopilot engagement in the FCOM is MDA for a non-precision approach, or 160ft AGL if CAT2 or CAT3 is NOT displayed on the FMA.

As long as you have CAT2 or CAT3 displayed on the FMA, the autopilot is certified to remain engaged throughout the flare and rollout, and indeed this is the point.

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Kevin Hall
8 hours ago, Lauri Sivuoja said:

Just tried autoland using MDA and had no problems. Are your findings consistent (DH ok, MDA nogo)?

Did it flare? If it's OK for you with MDA selected then that's how it should be. For me it only flares with DH selected. I found that with MDA selected all the autoland indications are correct and the FMA shows FLARE but the aircraft doesn't flare so it lands hard. It seems to be one of those bugs which only affect some users, not all.

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L'a^ûri S'i*v(uoj)=a
26 minutes ago, kevinh said:

Did it flare? If it's OK for you with MDA selected then that's how it should be. For me it only flares with DH selected. I found that with MDA selected all the autoland indications are correct and the FMA shows FLARE but the aircraft doesn't flare so it lands hard. It seems to be one of those bugs which only affect some users, not all.

Didnt have any recording device but would estimate touchdown to be about 130ft/min. So yes, it flared.

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Hi, let me give you my  humble input about the auto land "problem". When i first saw this thread, I decided to test the auto land(I never auto land,=). Hopped on the plane without configuring the MCDU (meaning i didn't fill the FROM/TO, nor did i filled out the weights on the perf page). Took off , and landed , slamming the airplane into the runway pavement. On the second try, i filled out both FROM/TO line, and the weights on the perf page, without putting the MDA or DA. This second time the airplane flare as expect, kissing the runway pavement. Now my conclusion is that in order for the plane to flare, the FMGS has to have FROM/TO lines , and the Perf page has to be filled out. 

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Marcel Semelka
42 minutes ago, joseabreu said:

...

Now my conclusion is that in order for the plane to flare, the FMGS has to have FROM/TO lines , and the Perf page has to be filled out. 

Nope, can't be the problem either...

On both tries I did (on video in this thread) the FMGS was completely filled going from EDDT to EDDT with weights, filled approach phase page (QHN, wind etc.) and so on, pretty much like in a normal flight.

I think the developers need to take a closer look at the autoland logic and or maybe the FBW that was changed with the latest update...

Unfortunately I don't have the time to sit in front of FSX and do autolands throughout the day, I hope the devs will find the problem and can fix it.

 

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NilsUnger

Let me give you my humble input. I am still floating and floating and floating...

I think I have done maybe 5 autolandings with this and the previous versions and always floated over the runway. 

After the long float the touch down is nice and gentle.

I always fill out INIT pages and approach page and put in DH. 

Strange that there are so different experiences among the users. 

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Norman S Bowman

Just to add my findings since I have been following this topic.

Two flights using autoland with full details input into FMGS rates for both flights in the 150-200ft range with a slight amount of flare on both occasions.

When I do a manual landing I seem to flare just a little more and perhaps a little earlier.

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Simon Kelsey

Just to follow up on something I said earlier...

Even for no DH, I would probably still enter 0 in the minimums field.


I had a hunch that you could also enter 'NO' in the DH field, but I couldn't remember for certain where I'd seen it or if I was actually thinking about the A320 or another type.

Checking the manuals as a result of this topic, I can indeed confirm that the RADIO field should, in theory, accept an entry of 'NO' for CAT IIIb No DH ops.

Not tried it in the FSLabs, though!

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Bryan Richards
On 12/23/2016 at 6:22 PM, dermobb said:

always floated over the runway. 

After the long float the touch down is nice and gentle.

The float does seem a bit much doesn't it? On 2 occasions I almost over ran a 9500+ runway using auto brake low when the plane barely managed to touch down within the "carpet". I have to remember to use medium when doing auto lands. 

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Nicolas Matus

I've had no issues with the Autoland on last update, but I find the "hovering" over the Touchdown zone rather interesting. In fact, its a successful autoland, but  most of the times the bus aims to touchdown at the thick bars with a firm landing (not a HARD one, but rather a firm one). 

Also, it is very important that if the plane does not react as it should do, take over. (I've seen situations on RW autolands where the pilot would go around at 50-40ft due to an autoland warning or incorrect behavior.)

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Camille MOUCHEL
19 minutes ago, BassmanFromHell said:

I have done a few autolands in ths FSL bus and whether using MDA or DH I always get greasers....

 

Aaron

-oOo-

lucky you, haven't got one yet

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NilsUnger
20 hours ago, bgrade said:

The float does seem a bit much doesn't it? On 2 occasions I almost over ran a 9500+ runway using auto brake low when the plane barely managed to touch down within the "carpet". I have to remember to use medium when doing auto lands. 

Yes, that's what I will be doing for the time being. 

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Aaron Brand

Just to add that I always autoland into Gatwick when arriving on 26L because of the 2 second long pause I get over the TDZ when UK2000 Heathrow loads at that exact point (happens with Aerosoft Heathrow as well before anyone says anything).  No such problem when landing on 08R

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Norman S Bowman

When I land at UK2000 EGLL and EGKK I am not getting any micro-stutter over the TDZ.

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Andrew Wilson
On 1/2/2017 at 0:10 PM, Andrew Wilson said:

If anyone experiences the aircraft not flaring - can you quickly save the flight before it lands and post the files here?

Anyone?

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Andrew Wilson

Thanks Kevin,

Please zip up the files in your FSX/FSLabs/A320/PanelState folder (only the ones for the situation you've saved) and upload here if you can. 

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Kevin Hall
4 hours ago, Andrew Wilson said:

Thanks Kevin,

Please zip up the files in your FSX/FSLabs/A320/PanelState folder (only the ones for the situation you've saved) and upload here if you can. 

Hi Andrew

Sorry for the delay, I couldn't reproduce it at first then the sim started playing up. In my installation, three conditions have to be met for the no flare condition to occur.

1. MDA set instead of DH

2. Allow APPR phase to be set automatically, not selected manually in the MCDU.

3. Using selected speed, not managed.

Hope this helps to track down the cause.

no_flare.FLT.zip

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Andrew Wilson

Hi Kevin,

We're struggling here, because there's no link between those items you listed and the flare logic in either the Flight Guidance system or the ELAC's. 

Can you try to reproduce the issue again, and this time leave the Captain MCDU open on the FPLN page.

Just check for me the FMGC doesn't reboot during the final stages of approach? It should remain on the FPLN page.

It really should be possible to reproduce this issue when using a DH - perhaps you could try and fly a few more landings with DH?

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Kevin Hall
1 hour ago, Andrew Wilson said:

Hi Kevin,

We're struggling here, because there's no link between those items you listed and the flare logic in either the Flight Guidance system or the ELAC's. 

Can you try to reproduce the issue again, and this time leave the Captain MCDU open on the FPLN page.

Just check for me the FMGC doesn't reboot during the final stages of approach? It should remain on the FPLN page.

It really should be possible to reproduce this issue when using a DH - perhaps you could try and fly a few more landings with DH?

Hi Andrew,

Here's another non-flare landing save with the Capt MCDU open in FPLN page. Same conditions as before. Note, although it doesn't flare I do get FLARE GREEN on the PFD every time. I'm not suggesting these three conditions are the direct cause, but so far if they aren't all true it flares normally. Not 100% sure, so I'll try and eliminate the APPR PHASE selection tomorrow as that seems the least likely.

It's getting late now, so I'll try a few autolands tomorrow with the same conditions except DH selected and let you know how it goes.

I've only seen the FMGCs go offline once today, I got an ECAM message about nav position disagreement and both MCDUs showed no FMGC prompt in the Menu page. I had to abandon that flight. Other than that they've stayed running. I didn't realise they mght reboot,

Cheers

no_flare2.FLT.zip

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B_r_u_n_o-R_o_l_o

I just completed a flight to TJSJ ILS10 (DH was set to 200) and "tested" the autoland, well, it did not go very well, the plane landed very hard @ 720fpm. I have a video, but I did not get to save any status as I was just looking at the forums after landing. I will try another ILS there and will save the files as per Andrew's request....

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B_r_u_n_o-R_o_l_o

2nd test, same result, no flare (even though FMA was in Flare mode), hard landing -720fpm. Attaching ZIP file as requested. I also have videos if needed.

 

FSL.zip

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Camille MOUCHEL

@Andrew

I can do a few autoland his night, is there anything that you want me to test and / or display to show I ?


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