PMDG 777 KSFO 28L Threshhold Problem

[scandinavian13]

 

 

Are airfields level so that all thresholds are at the same altitude?

 

Real world?  No.

 

FSX?  Yes.

[Guest RWFeldman]

Umm sounds familiar. Oh,  believe someone found out recently there is sea wall there!

[3-2-1-Now]

I forget the actual physics and location of the whole thing

 

It is rigged so that when in the correct landing attitude, with the main wheels touching the ground (but oleos fully extended), it reads zero.

 

Best regards,

Robin.

[scandinavian13]

 

 

It is rigged so that when in the correct landing attitude, with the main wheels touching the ground (but oleos fully extended), it reads zero.

 

Thought it was something like that, but didn't want to go fact checking, so thanks!  :lol:

[paulyg123]

I more note to hit on.  I did much testing on this and came to a conclusion, that this sudden loss of altitude/crash only happens over runways right next to water OR runways on a plateau - in both cases the elevation right before the threshold is 30-50 feet different then the threshold (a sudden change in elevation).  I also noticed if I come in a bit high on the approach, I never crashed, but if I come in low on those runways mentioned above, I always crashed.  And the crash was an unrealistic vertical slam of 50 feet down as shown in my youtube video posted above.

 

Again, the mesh setting of 19 solved it for me.

 

 

One more thing- I am glad the site is back - it seemed like a week it crashed. I am off to do 4 hours in a 777-200 full motion simulator.  I'll post videos of it.

[denthibbe]

Again, the mesh setting of 19 solved it for me.

 

 

+1

Same problem occurs on Aerosoft's Nice Côte d'Azur scenery landing on 04L

Setting mesh resolution on 19m solved it for me too (10m was already too low as I still crashed when landing a bit too low)

 

This is what happened :

[FlyCathay]

I did some experiments when avsim was down. I am pretty sure it is FS Global mesh problem, since after I disable it, it is fine.

[Great Ozzie]

If I approach the runway low (3 red on PAPI) just as I cross the threshold the runway jumps up about 30' or so

This has happened to me in the PMDG 747 @ KSFO RWY 28R... also @ KLGA RWY 13.  In my case, I can be "On Glidepath" -- handflying or Autoland, doesn't matter -- I get a crash into something invisible.

 

It would also explain why (as someone mentioned) it seems to happen on over-the-water approaches.

That is the only thing I find consistent; happens where the water and threshold are in very close proximity.  I have heard too it was a Mesh problem (I mainly have the Orbx areas e.g. PNW etc.).  I've had it happen on at least two different systems (one XP x64, the other Win7 x64).

 

I've tried also with the default 747 and the PMDG 737.  No problems at both locations with either airplane.  In fact, I can fly well below glidepath with the PMDG 737 w/ no problem (no invisible crash barrier).

 

The only way I know to avoid is to remember where it happens (e.g. @ KSFO & KLGA) and to come in "well high" i.e. well Above Glidepath when flying the PMDG 747.

 

 

I more note to hit on.

Yes... similar to you, Paul.

 

Thanks regarding the Mesh = 19 setting... but for some strange reason, the sim absolutely refuses to allow me to set it below 10.  Even if I edit the fsx.cfg to MESH_RESOLUTION=21 upon opening FSX the slider is at 10.

[Ed Kammerman]

Funny you mention Asiana. I've started flight 212 RKSI to KSFO in the PMDG 777. Let's see what happens. I'm using Flightbeam's KSFO scenery. I'll report back.

Landed on 28L today using autoland ( Don't trust my old man eyes) No problems

[Tabs]

No way this is a problem with the aircraft - has to be scenery related.

[Jetset408]

It must be the KPMG model. Haven't had the same issue with the PwC or EY model.....

[DOGANG KIM]

I tested several times.

 

This bug also appears with default planes and default airports.

 

So I think this is a FSX native bug.

 

 

Default 737, 747, A320, PMDG 747, 777, 737, Aerosoft A320,321, Level-D 767 .. All same. The bug appears. !

 

What is the reason and solution? I have no idea....

 

(Sorry for my poor English)

[nzeddy]

Yep, it's an FSX bug.

[DOGANG KIM]

Yep, it's an FSX bug.

 

Do you know any link or site about this issue? Some add-on scenery requires 5m mesh resolution. But the scenery has cliff threshold !!

[3-2-1-Now]

The problem is with the way FSX terrain crash detection works.

 

It's like you occasionally see the aircraft jumping on the ground, particularly at KSEA, if the sim is busy with other tasks and can't update the terrain fast enough. In that case, as the elevation changed due to changes in the resolution of the mesh, it would cause the aircraft to bounce/crash.

 

I suspect what is happening is as the coastline LOD is increased (witnessed by the shape changing as you approach it) then the crash boundary built by the sim is not exactly in line with the visible terrain for whatever reason.

 

What would be interesting to do is taxi from the other direction and see where it is. It could literally be an invisible wall, or something worse.

 

Best regards,

Robin.