A320 wind info on ND

[WhyByFlier]

I know that the wind arrow is Magnetic and the digital wind is True on the ND and I remember having to find it and answer it in FCOM in my TR about 5 years ago but now I can not see any confirmation of this in FCOM. Is anyone able to provide me with a reference? Thanks.

[I-2021]

Hi, chapter 31 indications on ND.

Cheers.

[WhyByFlier]

Thank you for your response but in the easyJet FCOMs it doesn't say this. It says:

ADIRS provides the wind direction and speed. The digital direction and the analog direction (green arrow) indicate the north reference that is in use.

That's applicable to 'ALL' and we have a broad range of MSNs. It doesn't say True or Magnetic on the ND and the arrow and digital read out give no indication contrary to what they say above.

Any other ideas?

[compressor stall]

The digital display is always reference true north. The Arrow wind reference depends on what screen you have selected.

For ARC mode
Speed and Wind Indications
In any of the ND modes, the following data are displayed on the L upper corner of the ND:
...
- wind origin and force digital values in degress and knots, the wind origin is given with respect to the true North)
- wind direction in analog form, represented by means of a green arrow orientated with respect to the true north. This arrow is
displayed only if the wind force is greater than 2 knots..

For ROSE modes
In the left upper corner, the A/C actual ground speed and true
airspeed indications are provided, as well as the wind data
(direction/force: the direction is given with respect to the
true North in digital form, and with respect to the heading
dial axis (aircraft heading) in analog form (arrow).

Info all in the A320 AMM

[RAD_ALT_ALIVE_2]

I think you'll find that it's like that because of a mod status introduced a few years ago. It was introduced to tie in with aircraft that have the NORTH REF p/b-sw.

If your aircraft don't have that switch then both indicators reflect magnetic information.

[compressor stall]

Interesting. Was it a generic mod upgrade, or one done just for NORTH REF P/B fitted aircraft?

I'd say there are very few narrow body A320F aircraft with the NORTH REF P/B mod. I've checked a different company's AMM that definitely didn't have the NORTH REF P/B fitted, and the text is the same.

[RAD_ALT_ALIVE]

Looks like I've got my old moniker back...;)

I'm not sure CS. I noticed the change to the FCOM text after coming back from an aircraft that had the NR p/b-sw. In trying to think like Airbus people would, I guess I just assumed.

[timmyEGCC]

It's an interesting topic. So to summarise, newer A320s with no MAG/TRUE switch would have Magnetic GREEN ARROW and Magnetic DIGITAL wind info on the ND correct?

I've been monitoring the IRS 1/2/3 wind info on MCDU IRS MONITOR page (yeah I should get a life right?:8) and although FCOM DSC-22_20-50-10 says the wind info there is in reference to TRUE bearing, it seems to me (after comparing each of the three wind data with ND indications, in regions with Mag Var more than 10°) that it's actually MAGNETIC? Could someone shed some light on this?

The only 'TRUE' wind direction I could find was in PROG REPORT page.

May be I'm missing something.

[767-300ER]

Slightly off topic...

I believe that the wind display starts at 100 kts g/s(?)

How does the system calculate wind velocity and direction while the airplane is still firmly attached to the ground?

:hmm:

[OPEN DES]

76, it doesnt! It will only indicate effective tailwind/headwind component.

[compressor stall]

Right…. Had a good look over some old FCOMs from a few different places - and the inside of a bottle of red :\

If your aircraft has NOT had the software upgrade 34-1368 you will see:

ADIRS furnishes the wind direction and speed. The digital direction and the analog direction (green arrow) reflect both the true north reference.

If it has had the software upgrade 34-1368 (but no hardware pushbuttons fitted) you will see:

ADIRS furnishes the wind direction and speed. The digital direction and the analog direction (green arrow) indicate the north reference in use.

If you have had the upgrade and the hardware pushbuttons fitted and the Polar Nav Function activated, you will see:

ADIRS furnishes the wind direction and speed. The digital direction is with respect to true north, and the analog direction (green arrow) is with respect to magnetic north [...unless TRUE is selected when it references true!].