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Autoland update 184


Camille MOUCHEL

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Andrew Wilson

Actually - I'll post here so that others can try too:

 

Can you download AFSD v4.41 from here: 

http://www.aero.sors.fr/designer_pilot_utilities.html

When you're doing an Autoland, run AFSD and have it displaying the flight controls tab so that you can see pitch trim, elevator and aileron controls. 

If you can then take a video of an Autoland with AFSD running next to FSX - it might show us a little more about what's happening. 

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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.

Aidan le Gras

We do them and here are our limitations for a 'satisfactory' autoland, assuming we were able to make note of all of these items during the landing:

Definition of a satisfactory autoland:

no system failure occurs

no flare failure occurs 

no decrab failure occurs 

touchdown occurs between 150 metres and 750 metres of the threshold, assuming a 'normal' GS antenna location  (note that outside of the TDZ is ok )

Nose wheel touchdown occurs within 8 metres of the runway centreline  

Touchdown vertical speed does not exceed 360 feet per minute. 

Bank angle does not exceed 7 degrees!

nosewheel does not travel beyond 8 metres of the runway centreline. 

Pitch angle does not exceed safe tail clearance for plane. 

Land finally, no rollout failure occurs. 

And if all the above goes well then you don't have to make a tech log entry!

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Zeljko Budovic

I tried to reproduce this 3 times using kevinh's sugestion. It happened only once, at first try, but unfortunately i didn't save any data - it was a first try, just to see if this happens on my system. I landed two more times with same settings, and both times autoland worked perfectly. 

But i saw something when this happened, there was a glideslope deviation about 100ft - probably wind gust(it was reported in AS2016 metar)or something else weather related. In this case, nothing is wrong with autoland system, this is why pilots are monitoring autolandings. The plane was a bit high and tried to corect this with a bit of a dive, then flare was initiated but was to late and landing rate was over 500 fpm. I belive autoland was working well, becouse i could see autopilot making some actions - sideslip was corrected, centerline maintained on rollout etc. 

With another two landings, there was no glideslope deviations and landing was just perfect, less then 100 fpm

 

I tried one more time just now, there was a glideslope deviation but autopilot did not tried to correct it with a dive, and landing was perfect again

 

Edited by lodestar
Update
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B_r_u_n_o-R_o_l_o

@Andrew Wilson

Here is a quick test I made, this time touch down shows around 500fpm (yesterday was 700fpm weights  ZFW: 131668  T.O Weight:148985 & Landing weight: 136290)

For today I just took off with the default weights the FSL loads with ZFW 125.6/27.7)

 

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B_r_u_n_o-R_o_l_o

Hey Howard, how are you mate? No I actually have not done so, I can give it a shot though

Edit: I had a look @ the FCTM and it says:
2) Thrust levers set to idle
If thrust levers are set to IDLE, A/THR is set to off. This technique is usually used
in descent, when the A/THR is in THR IDLE, or at landing. During flare, with the
A/THR active, the thrust levers are set to the CLB detent. Then, when thrust
reduction is required for landing, the thrust levers should be moved smoothly and
set to the IDLE stop. This will retard thrust, and set A/THR to off. As a reminder,
the “RETARD” aural alert will sound. In flare, this aural alert will occur at 20 feet,
except in the case of autoland, where it occurs at 10 feet.

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Norman S Bowman

Hi,

Just carried out a couple of landings using autoland and used managed speed and then full auto-thrust and viewed from the side and a three-quater view nothing untoward to report .Nice landings at around the 60ton weight and saw the flare with landing rates of 320ft and 280ft.

I am happy with the outcome. 

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Zeljko Budovic

Airbus test pilots recommendation is to set thrust levers to idle when you hear "retard" call, just "slam" levers to idle then ^_^ . At 50ft is too early in any case, except in situations when your descent rate is realy high. Or you can start moving them back(slowly) at 30-40ft, autothrottle will still be active until idle is reached, but you will limit how high thrust can go

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Kevin Hall

@Andrew Wilson Hi Andrew, I've made some more tests and I was able to get "no flare" landings with managed speed and by selecting APPR PHASE manually. So I think they were a red herring. I then tried an autoland with DH set to 200 feet and it didn't flare either (DH= 100 feet flares fine). Sometimes when it fails to flare there was an autoland warning at the minimums callout.

I tried landing with MDA set to 100 feet above threshold and it flared. So it appears that the no flare condition might be to do with the DH/DA rather than it being a DH or MDA selection. It seems as if a DH of 100 feet (or a DA of 100 ft above threshold) will flare. Increasing to 200 feet and no flare happens. The higher DH/DA could be delaying the flare, reducing it's effect or preventing it altogether. Does this make more sense in relation to the models concerned?

Maybe the investigation should be the other way round, looking at what might prevent flare from occurring when flare engaged, or what might modify the flare law to the extent that it ceases to be effective. Using the wrong input for logic or an equation is a common cause of bugs in simulation software in my experience. Could that be the case here?

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B_r_u_n_o-R_o_l_o

in both videos, I did set the throttles to idle when "retard" was announced. The FMA shows FLARE mode, but I dont think that the rate of descent shown in the video is an acceptable rate (based on the comments from @Willie Nelson), I am looking through my airbus doc to see if I can find something related to that.

Do you guys feel that the autoland was OK in both videos I posted? 

 

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H0wa_Rd_15aac5

I've tried seven auto-lands from the same saved flight and the v/s is never less than 350 and typically 400 to 500 fps with virtually zero wind.

The reason I suggested not moving the levers to idle until roll-out was to see if the auto-thrust retard mode on its own improved the landing but for me it does not.

As an aside does anyone know what happens on the real aircraft if you don't retard the levers on auto-land. On the A320X if you fail to do so the FMA says THRUST IDLE and there is a fleeting IDLE on the E/WD. The aircraft then just travels off the end of the runway even with maximum braking.

 

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Zeljko Budovic

@DescendDescend With Airbus, you must retard levers on landing. If you don't do it, it's just going to maintain selected / managed speed. And spoilers will not be deployed(thrust must be at idle)so your braking will not be so effective - especialy if autothrottle is still maintaining app speed :lol:

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Zeljko Budovic

it's even worse with airbus, autobrakes activation upon landing depends on spoilers deployment. 

@njflyer I watched your videos now, those landings are hard compared to mine, i did 5-6 tests today on some flytampa airports. Which airport / runway/ scenery is in your videos?

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B_r_u_n_o-R_o_l_o

Yes that is a bit of a mistery, I wonder if this is related to the joystick (maybe too much background "noise" from it), although I use FSUIPC for all axis... Let's see if @Andrew Wilson & team figure it out.

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H0wa_Rd_15aac5
6 hours ago, lodestar said:

@DescendDescend With Airbus, you must retard levers on landing. If you don't do it, it's just going to maintain selected / managed speed. And spoilers will not be deployed(thrust must be at idle)so your braking will not be so effective - especialy if autothrottle is still maintaining app speed :lol:

 

5 hours ago, njflyer said:

@lodestar yes that was my assumption as well, specially after reading the FCTM (see post above).

Its a bit off topic really but for Auto-lands there is a third mode (beside THRUST and  SPEED) called RETARD MODE which should set the thrust to idle (if in LAND mode) at touch down even of you don't move the levers or move them late during roll-out). RETARD MODE remains engaged after touchdown. Obviously you should move the levers to idle for other reasons. The question I was asking was, if the RETARD MODE has set idle then why does the A320 not stop with full manual brakes? See 1.22.30 around page 64/65. I'll try it again later.

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Zeljko Budovic
3 hours ago, DescendDescend said:

 

Its a bit off topic really but for Auto-lands there is a third mode (beside THRUST and  SPEED) called RETARD MODE which should set the thrust to idle (if in LAND mode) at touch down even of you don't move the levers or move them late during roll-out). RETARD MODE remains engaged after touchdown. Obviously you should move the levers to idle for other reasons. The question I was asking was, if the RETARD MODE has set idle then why does the A320 not stop with full manual brakes? See 1.22.30 around page 64/65. I'll try it again later.

Probably becouse if both thrust levers are not at idle there will be no spoiler deployment and without spoilers - no autobrake(depends on MSN, some will deploy spoilers regardless of thrust levers position). Even if you apply manual braking, it's not effective becouse spoilers are not deployed

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Andrew Wilson

We're still not sure what the problem is - but we're working on / testing some updates to the flare routine. 

Idle thrust is commanded during the flare on touchdown - you should have no problem stopping with manual braking.

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H0wa_Rd_15aac5

Hi Andrew. I just discovered that my pedal drivers (Saitek) didn't load properly hence no manual braking. Worked okay when I tried it again. Apologies.

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Norman S Bowman

Hi All,

This is one for Kevin .I used a DH of 200ft on both of my autolands and by viewing from the side observed that the aircraft flared at 40ft then the nose came back to a n even posture then a slight flare to touchdown towards the end of the TDZ.

I will try a couple more landings this evening just using MDA with full autolands and will see what is happening on my set up.I only use a Logitech 3D Pro joystick,no pedals etc.The joystick is mapped using FSX controls .

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Andrew Wilson
48 minutes ago, lodestar said:

@Andrew Wilson Andrew, can you tell us which MSN is modeled? It would be nice to know becouse of software changes / different FCOM's available on internet

Unfortunately we can't divulge that - but I can tell you the FMGS is Thales FMS2 Rev2+ S4 and ELAC L93's. 

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To all of you that are having autoland flare issues try the following and let us know:

Perform an approach in which you will be fully established/configured (config and speed) with a 20nm final. Do not touch anything within the 20nm and see if it flares ok. If it does it will be a great help to us confirming some findings.

Marios 

P.S. And no weather of course so there will be no indirect influence.

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B_r_u_n_o-R_o_l_o

Hi @Marios

Test1 ILS 10 TJSJ No Weather:

I tested as per your request (+20NM Final in Landing configuration and no weather)  and it appears the FPM, @ touchdown was around 300FPM or so.. Better than my previous attempts for sure. I have a video if you wish, let me know if I shall upload it.

Test2 ILS10 TJSJ No Weather:

Taxied back to RW10, and set a FP T.O RW10,  ILS10 (NO SID, STAR or VIA), flew a standard pattern and intercepted the IAF and set up the plane according to schedule (Flaps, Gear),   set up for Autoland and this time touchdown was a bit harder @ 400FPM

Test3 ILS10 TSJS using ASN:

Same test as above, except this time, for unknown reasons, the Autoland functionned properly with a smooth touchdown

I am not sure why , the only difference between these test was the weather, and I usually get "bad" autoland when using ASN (as seen in previous videos in above posts)

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B_r_u_n_o-R_o_l_o

@kevinh I am puzzled, see my post above I edited as I ran a few more tests, I didn't get a normal flare on the 20+ miles final, but got it on my 3rd attempt using ASN..

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Norman S Bowman

Hi@njflyer,

Have you viewed your aircraft from the external side view.I thought at one stage that I was not detecting a flare however when I viewed the aircraft doing a full autoland the flare and a smooth touchdown was present.

It may be worth a look!

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Kevin Hall
21 minutes ago, njflyer said:

@kevinh I am puzzled, see my post above I edited as I ran a few more tests, I didn't get a normal flare on the 20+ miles final, but got it on my 3rd attempt using ASN..

The test was to see whether a long stabilised approach affects the autoland touchdown. We were just asked to report results. Why is my result puzzling you?

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B_r_u_n_o-R_o_l_o
1 hour ago, DescendDescend said:

4-500 fpm for me. A bit less than 20 miles for fully configured. G/S captured at 2000 feet. MDA 200. Done from a saved flight.

Hey Howard,

btw I tried the RETARD MODE you mentioned earlier, and indeed without touching the throttles upon touch down, I noticed FMA announced THR IDLE (can't remember the exact message but something like this)

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Flow Bloisi

Hi guys,

 

Im working a lot on this wonderful bus but one big problem remain, since the last update i have always touchdown between -300ft and -400ft which is bad i think.I do the following:

- Begin light flare between 20ft  and 40ft th

- Flare at RETARD about 20ft

 

But im still got hard landing, how do you land it since this update ? there is a lot of difference on the flare.

 

Note. Im using A320 wizzair IAE 

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Kevin Hall
19 hours ago, njflyer said:

@kevinh because your testing yelled different results, yours ended in a smooth touchdown, whereas mine resulted a TD -300fpm ... 

But I didn't mention the touchdown rate, just that it flared normally. For me if it doesn't flare at all there's a clear problem with the simulation. If it flares to a reasonable degree then I'm happy.

Your result and my result are on different installations of the A320-X. Some variation is to be expected, especially as framerates widely from user to user. It isn't for you to question my result. Any more than I questioned people in this thread who didn't find the solution that works for me (setting DH < 100) to be useful.

Also, a TD rate of 300 fpm is certainly not unacceptable for an autoland. It represents a considerable reduction in the 700 fpm descent rate pre-flare and is firm enough for safety (a "greaser" certainly isn't as safe on a wet runway).

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B_r_u_n_o-R_o_l_o
2 hours ago, kevinh said:

But I didn't mention the touchdown rate, just that it flared normally. For me if it doesn't flare at all there's a clear problem with the simulation. If it flares to a reasonable degree then I'm happy.

Your result and my result are on different installations of the A320-X. Some variation is to be expected, especially as framerates widely from user to user. It isn't for you to question my result. Any more than I questioned people in this thread who didn't find the solution that works for me (setting DH < 100) to be useful.

Also, a TD rate of 300 fpm is certainly not unacceptable for an autoland. It represents a considerable reduction in the 700 fpm descent rate pre-flare and is firm enough for safety (a "greaser" certainly isn't as safe on a wet runway).

1) the TD rate of 300 was the first time I ever had such a "smooth" touchdown

2) I understand results will vary between users, this is not xbox and I accept that, I dont accept you telling me what to question, specially when I only stated that I was puzzled to see different results, if you feel that I was questioning you or your test, or was attacking you, you are wrong.

3) If the Aircraft flares and results in a 500-700fpm as I have consistently noticed, then it doesn't matter that the airplane flare or not, in my case the A320 will flare and FMA indicates FLARE but TD rates are unacceptable.  I have experienced flares IRL that resulted in hard touch down more than once

4) I don't even use autoland for my flights unless the approach requires it, I was simply trying to help, lesson learned. Case closed

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Flow Bloisi

Ok guys, i tried autoland this afternoon on omdb runway 30L with active sky next and few winds 350/06kt.The plane flare at 30ft, retard 10ft touchdown -177ft/mn with a DH set to 200.I think this is acceptable landing rate.I try a full manual landing on the same runway touchdown -323ft/mn then i change the airport and land into LFLL 36R with DH200 and disconnecting AP at 1000ft like i often do when runway is sight, TD -226fr/mn.So i think we are all have to change our minds with the landing flare and pay it a lot of attention.

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Zeljko Budovic

Ok, i did a lot of test and here is what i found: It's definitely something about elevation. Do you(with hard landings)use ftx vector? If so, run vector elevation correction and Pete's "MakeRunways" utility, you can find it here http://www.schiratti.com/dowson.html (not sure the second is needed for FSL, but it's needed for other addons).

They need to be run every time you install, activate / deactivate new scenery. I found this to be issue with autoland, FSL don't flare becouse it "thinks" it's not time to flare yet, becouse of elevation issues.  @Andrew Wilson  i tested it several times, and i'm sure. I have no a idea how FSL A320 reads elevations, from FSX or from it's own database, but i'm sure this is causing problems. When you install addon airport and elevation is different then stock FSX, there is a FSX bug - it reads elevations from scenery.cfg and it takes into account the lowest entry(which is a stock FSX Airport) - this is why ORBX AEC is so low in scenery.cfg. 

Try to install Flytampa Dubai, don't run Vector elevation correction and "MakeRunways" and it will slam into the runway every time. After you run it, every time landing should be a kiss.

This is how it works on my system, and i tested it several times with different addon airports that have different elevation then stock FSX airports

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B_r_u_n_o-R_o_l_o

Hey @lodestar good find! you might be on to something here, on my end I always see the FLARE on the FMA, it's just the TD rate that is way out of wack. When you test autoland, do you get FLARE announced on the FMA at all? 

 

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Flow Bloisi

In my case i don't use ftx vector so i can't tell if the problem is here but 177ft/mn was my touchdown on autoland flytampa Dubai.Maybe some poeple have to try your suggestion.

 

I do another flight this night and manually landed at 151ft/mn, what i do is the following:

 

- 50ft begin to decrease V/S but slowly

- 20ft juste before RETARD alert, a more intensive flare (5° pitch up) then the plane float a few time like two second and i hear 10ft and 5ft coming smoothly.This bus is crazy to land if you don't pay attention to it.

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Zeljko Budovic

@njflyer yes, i see the FLARE but is too late 

@Palaio Odeyo i hope this is the answer, please report if you test it

@Bloisi manual landing is not the problem, autoland has a problem in some situations, and i hope this was the only problem. Not that i realy use autoland, but i'd like to have it working properly in case of some low visibility approach

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