Final Approach with ILS (specifically KSFO ILS 28L)

[boguwei 0]

I noticed this problem the other day when I was coming into SFO on runway 28L.

 

I wanted to test out the autoland feature so I was coming in to intercept the localizer at a heading hold. The correct frequency and heading was input manually into the CDU via the NAV RAD page, and approach was armed.

 

The 747 intercepted the glide slope no problem and I got a LAND 3 just fine.

BUT, about 100 feet AGL, the simulator would exit and say that I had crashed - presumably into the fence next to the ocean as I was about to land.

 

During this, I can see that the plane is following the diamonds perfectly until 100 ft AGL or so, when the aircraft seems to very quickly fall beneath the glide slope markers (even though vertical descent rate did not change). It's almost as if the vertical profile is programmed to shallow out right before the runway.

 

The aircraft maintained a constant rate of descent and did not adjust for the veritcal diamond moving upwards very quickly that last 100 ft or so.

 

Was I doing something wrong, or is it just an FSX bug? I feel like even if it was an FSX bug, the aircraft should have compensated for the diamond moving up and shallowed out with the ILS profile?

[PHXMD-11 86]

I would turn off the detect crashes feature in the fsx options menu. Try that and it may work.

[boguwei 0]

I would turn off the detect crashes feature in the fsx options menu. Try that and it may work.

 

Will do. I just wanted to make sure it wasn't me being stupid and not using the MCP correctly or something.

[dmwalker 601]

I haven't had any problem with ILS28L but I use the default scenery. Do you use add-on scenery at KSFO which might cause this problem?

[ajpongress 467]

FSX geometry doesn't really sync up with what you see visually.

A building/fence post/tree can extend beyond the actual graphic for the purposes of crash detection.

 

As mentioned, just disable crash detection. It's not realistic and you don't need it stopping a 4+ hour flight on short final.

[boguwei 0]

Ok. Thanks for the feedback.

 

I disabled crash detection and everything worked out fine.

(For the record, I'm pretty sure I use the default scenery, haven't installed any addons I can think of that would affect scenery geometries)

[dmwalker 601]

By all means disable the crash detection. I just wanted to make the point that there isn't any structure or fence or feature at or near the beginning of the runway and, even with the crash detection disabled, I presume there is still the anomaly of the ILS display which boguwei still has consistently and I don't have consistently. Anyway, it's not a big deal but I just thought I'd mention it.

[boguwei 0]

I presume there is still the anomaly of the ILS display which boguwei still has consistently and I don't have consistently.

 

There was indeed still the anomaly when I tried again on 28L. You're right, it's no big deal, but it is certainly odd.

 

Either way, tried the same procedure with 28R and the aircraft followed the glide slope just fine (crash detection off though, as I suspect trip7cap is right about the extended geometries). Weird little idiosyncrasies in FSX I suppose.