Francesco Giacchetti wrote on Jun 8^th, 2020 at 3:04pm:


Same here on a LOT of other airports, for example EDDF.

I had terrain warning activation even when I was pushing back at some airport with mountainous nearby in 757

Scholli04 wrote on Jun 10^th, 2020 at 11:44am:

Because the terr warning from now on has this dedicated thread.
That doesn't necessarily mean there's no bug.
But there's at least one more party involved in the issue - the default scenery mesh. We are not sure if the mesh is perfect, so the mesh can be a reason for the false terr warnings.

Anyways, everyone is welcome to attach the flights saved right on the false terr warnings.   

Scholli04 wrote on Jun 12^th, 2020 at 6:32am:


Never say it's not in any FCOM, haha. In aviation, everything is written SOMEWHERE.

Major 757/767 operator:

"The GPWS does not provide an alert for flight toward vertically sheer
terrain or slow descents into terrain while in the landing configuration."


"When the aircraft is lower than 2000 feet above the terrain, terrain within 2000
feet of aircraft barometric altitude is displayed on the HSI/ND. Non-threat terrain
is depicted as several densities of dot patterns in green, amber, or red depending
on relative vertical distance between the aircraft and the terrain.

Note: (752PW) (763) The EGPWS terrain database, look-ahead terrain alerting,
and terrain display account for man-made obstructions.
When the aircraft is higher than 2000 feet above the terrain or within 400 feet of
the nearest airport runway elevation, terrain is not displayed.
Note: The GPWS look-ahead display is not designed to be used as an
independent navigation aid."

"The displays remain in view until the threat no longer exists or the TERR switch
is manually deselected."

Captain Sim wrote on Jun 12^th, 2020 at 2:20pm:


I have no idea! Not imputting anything here except the few lines about how it works for the users to see.

Captain Sim wrote on Jun 12^th, 2020 at 2:20pm:


That is absolutely untrue. The page posted is the best proof. It only explains the genral way the terrain awareness system works.
It's a nice proof though that you did not even understand, nor read, what I posted.

Once again: There is special protection around the approach area, so that for example on the circling at LOWI, the circling at LPMA, LDDU, GCLA (the list is long) there are no useless warnings triggered.

Have a look at ANY video of any of these approaches and tell me why there's never a terrain warning heared. Accoring to your manual it must be there.

And now tell me why, because according to your manuals the GPWS should go crazy while it doens't.

I, once again, tell you why: Because NOT ALL FEATURES ARE DOCUMENTED IN FCOMs. They might be documented in Boeing documents which are NOT PUBLIC.
To help your general understanding of flight manuals: FCOMs only contain that information which the manufacturer thinks a pilot must know.
See the 737MAX and MCAS for the best example. They did not believe the pilots must know, so it wasn't included.

An FCOM is a FLIGHT CREW Operations Manuals, not a DEVELOPERS manual... you need to look a bit further than that. Or just listen to some real pilots instead of constantly prooving ignorance.

Alex T wrote on Jun 12^th, 2020 at 7:42pm:

They think there are no obstacles around but we need proofs.