Wind Indicator Missing Sometimes

[paulyg123 135]

(I don't see a topic covering this - though I wish the SEARCH worked better)

 

On the PMDG 777, I noticed the wind indicator sometimes is there and sometimes it is not.  I fly with ACN and have live weather set asa  default.  In FSX I select weather option to ACN (if that matters)

 

Where does the wind indicator get tots data from?  Why the intermittent showing? 

 

Paul Gugliotta

[scandinavian13 5,192]

 

 

Where does the wind indicator get tots data from?

 

The IRS as a drift v heading metric, I believe.

 

 

 

Why the intermittent showing? 

 

No wind data, no display. Also, it won't show if you're on the ground and less than a certain speed (forget what the threshold is).

[pcubine 143]

Why the intermittent showing?

Infrequently the wind speed aloft will be nil. There will be no direction or speed displayed on the ND. Ground speed and True Air Speed will be within a knot of each other or maybe even equal.

[BrianW 124]

For wind data to display the TAS needs to be above 100 knots, and the wind speed needs to be above 5 knots.  Additionally the wind indicator is not displayed with the ND map in plan mode.

 

The wind data is calculated using inputs from:

The flight path angle

North and east velocity

True heading

ADIRU TAS

 

Values for the above are derived from the LNAV sub-function of the flight management computing function using inputs from the ADIRU, GPS, Navigation database, and nav radio data.

 

[paulyg123 135]

I should have been more descriptive. I was level at FL240. ACN active and I created and saved flight plan in ACN. My FMC is showing 25 kt cross wind at my altitude but indicator is blank. I will try not using ACN and see if FSX weather gets the indicator working

[pcubine 143]

ACN active and I created and saved flight plan in ACN.

What is ACN?

[walfob 10]

I think he means Active Cky Next!