Blackbird Sims / Milviz Forum Archive

I'm fully established on my apprach, starting at about 6NM out I got a "Caution, Terrain" warning which continued all the way until 4NM.
I was exactly on the approach profile, exactly following FD guidance for the RNAV 27 at EDFM.
Here's a video: https://youtu.be/XM_YlYc0hoM

Can you reproduce it again? Also trying with slower approach speed and vs above -1000 fps?
Anyway, you can cancel the alarm with the INHIB button on the glareshield. INHB message should display.

Tomas

I can reproduce it, yes.
I've just flown another approach where I got it.
ILS25L at EDDF. 3° GS, AP engaged and stable.
Speed 160 again until 4DME, resulting in a VS of about 800fpm to maintain the GS.
Terrain warning activated at about 5NM from the airport and continued until the gear was extended at 4NM.

And another one today, this time miles out over the open water - which the GPWS didn't want to believe:
https://youtu.be/hvjd8XVjZJI

Calvi, LFKC, LOC18 approach.

Is your position set correctly?
You are over the water, but your terrain display shows you over red terrain. Your zoom level is 5 miles so the radar is acting as if you are below minimum altitude at raising terrain, thus the GPWS calls

I'm fairly certain my position was within the required RNP1 specifics. When switching from RNAV to raw data operation (aka when comparing the distance to the FAF from the DME and from the FMS) they matched with about 0.2NM, the latter of which are probably caused by the slant range of the DME compared to the flat range of the GPS/FMS position.
There was no gross error of several miles as would have been necessary for such a big EGPWS messup.

I replicated your position and didn't receive any alarm.
I also found incongruencies in your terrain display. Please take a look at these pics:

This is your terrain image with a 5 NM range. Ground seems too close still you are quite away over water.

This is my position, rather similar to yours taking FL18 fix as a reference. Notice that terrain with 5 NM range doesn't show yet.

Now terrain displays but with 12.5 NM range, and still far from my position.


I don't know why the difference. Do you have the original Navigraph database? or an updated version?


Tomas

I'm using the current Navigraph AIRAC for the King Air, not the one that has been delivered with the P180.
When I updated my King Air the P180 was updated automatically it seems.