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TERRAIN TERRAIN

Started by J D ADAM, Mon, 26 Feb 2024 02:49

J D ADAM

Gentlemen,
I am repeatedly getting a terrain warning when established on the ILS.
This can occur on a flat landscape.
The question is "is this normal in the real world?

Cheers
Derek
NZAA

andrej

Hello Derek,
I confirm that I receive this warning as well. Usually happens one, but regularly on an approach (established on the ILS), with no real threat (i.e. airport is located in a flat surface area). I am too slow to record event (SITU). But if it happens today, I will try to do it.

Sincerely,
Andrej

Hardy Heinlin

It may be a small hill. The main factor is not the hill's height but how fast the radio altitude is decreasing.

There are some ILS approaches in the world that have a small terrain peak on the final (e.g. Seattle). Honeywell's real EGPWS contains a special database for such objects and inhibits known nuisance alerts accordingly. PSX has no such special database.

When you report such problems, it would be nice to know whether you're using an external scenery or the PSX scenery.


Regards,

|-|ardy


P.S.: For reference, see page 547 in the Aerowinx manual.

Bluestar

In the real world it is not unusual to get a Terrain alert off the high rise building on an approach.  During my last B737 sim session a couple of months ago I received a Terrain alert while one on an approach into KDAL.
Grace and Peace,

Bode

MFarhadi

I've had erroneous EGPWS warnings go off on me several times, but only with ATR76. Never had any with Airbus.
Mohammadreza Farhadi
Ex-pilot, current aerospace student

J D ADAM

Hardy and other gentlemen,

Thank you for your reply.

I do have P3D as eye candy.

Flying into home airport NZAA 23l established on the glideslope Cat3 I
receive several warnings.

If any of my great friends on this forum have time, could they please
fly this approach and tell me if I am imagining things!

Cheers
Derek

MFarhadi

I'm pretty (like 99.99%) sure that you "shouldn't" receive a GPWS warning during a CAT III. Can you give a rough RA or DME estimate on where you usually get those warnings?
Standard GPWS procedure during approach incorporates pilot's ability to see whether or not the warning's legible, through visual means. So, if you're doing a LVO approach (CAT II or CAT III) it basically means that you're not gonna see anything outta the windows. The whole certification process of the approach goes up in flames too; the flight tests do incorporate rigorous survey of the approach and missed-approach paths regarding terrain slope and obstacles.
Mohammadreza Farhadi
Ex-pilot, current aerospace student

Bluestar

Quote from: J D ADAM on Mon, 26 Feb 2024 21:03Hardy and other gentlemen,

Thank you for your reply.

I do have P3D as eye candy.

Flying into home airport NZAA 23l established on the glideslope Cat3 I
receive several warnings.

If any of my great friends on this forum have time, could they please
fly this approach and tell me if I am imagining things!

Cheers
Derek


Derek,

I just tried the ILS21L at NZAA without any issues.  My setup was P3dv6, Orbx North Island and Flightbeam NZAA.  My approach was from the north.  My suggestion would be to make sure that you cross EMRAD at 3,000.  Since I am almost always at or near MGLW my Gear is down and Flaps 20 prior to 10 miles and have the Spoilers Armed and Flaps 30 prior to 5 miles.  My touchdown rate is normally around 300 fpm at about 1,500 to 2,000 feet (Never short of 1,000).  Since I'm single pilot my landing checklist is the same as I used in the military "Gear, Flaps, Slats, Cleared to Land".  🤣   
Grace and Peace,

Bode