wind vector display...

[cagarini]

Good morning!

in the video linked bellow, of a bumpy approah into Anchorage, I observed that the wind is blowing at 20+ knot and being indicated in the ND until, all of a sudden and around 400 ft and as the AP get's disconnected it stops being displayed?

Is it meant to be that way? Airline option?

https://youtu.be/_21Ojt_Y01E?t=167

[G-CIVA]

The WV information is not in any way connected to or related to the A/P functions. Wind Vector information displayed on the ND (& in the CDU) comes from the IRUs.

I suspect as the aircraft is descending on the ILS it passes through a layer of strong, bumpy wind from the E coming from the mountains.  As the aircraft descends & exits that layer into smoother air below, the wind speed drops below 05kts.

The Wind Vector information blanks on the ND if the outside wind falls below 5kts (as described in the PSX Manual).

This is backed up by the SPD Tape stabilising & the amount of turbulence reducing on short finals.

[cagarini]

The WV information is not in any way connected to or related to the A/P functions. Wind Vector information displayed on the ND (& in the CDU) comes from the IRUs.

I suspect as the aircraft is descending on the ILS it passes through a layer of strong, bumpy wind from the E coming from the mountains.  As the aircraft descends & exits that layer into smoother air below, the wind speed drops below 05kts.

The Wind Vector information blanks on the ND if the outside wind falls below 5kts (as described in the PSX Manual).

This is backed up by the SPD Tape stabilising & the amount of turbulence reducing on short finals.

Yes, I thought about that before posting :-) but it looked to me liek a rather abrupt wind change from 25 knot to 5- ... but it's indeed probably teh reason.

I didn't check the orography there, but now that I did, there's indeed that mountainous terrain to the East.

Thx for your comment !

[Ton van Bochove]

PANC has some special wind conditions

https://youtu.be/_21Ojt_Y01E