ATIS Winds Pop Quiz

[FAD3C]

ATIS winds, T or M?
I have not been able to find any government issued documentation stating whether the winds in ATIS broadcasts are True or Magnetic. I understand ATC tower controllers read the METAR line into the ATIS but shouldn't it be Magnetic since we are "hearing it"? In the AIM under 1.4.1 (table) it specifies that "wind direction observations for landing and takeoff" should be in degrees magnetic except in the NDA.
Cheers

[landshark]

Magnetic

[Ki-ll]

The table in the AIM is pretty much verbatim from ICAO Annex 5, chapter page 3-4.
https://www.google.ca/url?sa=t&rct=j&q= ... etUKZaEksQ

wind direction (wind directions other than for a landing and ° take-off shall be expressed in degrees true; for landing and take-
off wind directions shall be expressed in degrees magnetic)

Also, I don't think the winds in the ATIS are exactly METAR winds, those are two different products and probably made by two different people.

[FAD3C]

Magnetic

Can you back up your answer?

[ThatArmyGuy]

+1 to Ki-ll

In general: anything written is true, anything verbal is magnetic.

[Ki-ll]

Here is a little more for you from ICAO Doc 4444 PANS, Page 11-26 paragraph a) in section 11.4.3.2.3
https://www.google.ca/url?sa=t&rct=j&q= ... 3X5QaWu6Hg

Note.— Information on surface wind direction provided to ATS units by the associated meteorological office is referenced to degrees true North. Information on surface wind direction obtained from the ATS surface wind indicator and passed to pilots by ATS units is given in degrees magnetic.

And a little more from Doc 4444 again on the definition of ATIS, page 1-6

Automatic terminal information service (ATIS). The automatic provision of current, routine information to arriving and departing aircraft throughout 24 hours or a specified portion thereof:
Data link-automatic terminal information service (D-ATIS). The provision of ATIS via data link.
Voice-automatic terminal information service (Voice-ATIS). The provision of ATIS by means of continuous and
repetitive voice broadcasts.

Combine that with ICAO Doc 8896 section 2.3.7.2 Note 1:
https://www.google.ca/url?sa=t&rct=j&q= ... p_iyhAZhVA

Wind direction reported to aircraft for landing or take-off purposes must be converted into degrees magnetic. This conversion is normally carried out by the ATS unit concerned.

So ATIS is a service for departing and arriving airplanes, which take off and land, and wind for take off and landing must be in degrees magnetic. I think that's good enough.

[FAD3C]

Then NAVCAN towers are potentially putting the information into the ATIS incorrectly. A friend told me all they do is read off the metar into the ATIS machine or the device they use.

[Ki-ll]

Then NAVCAN towers are potentially putting the information into the ATIS incorrectly. A friend told me all they do is read off the metar into the ATIS machine or the device they use.

Maybe the machine does everything for them?

[CpnCrunch]

If you call 1-877-517-2847 you can compare the ATIS to the METAR. You'll see that for YYJ and YVR the ATIS is 20 degrees different from the METAR, so it is definitely magnetic.

Perhaps your friend meant "we read it off the METAR and add/subtract the variation".

[FAD3C]

If you call 1-877-517-2847 you can compare the ATIS to the METAR. You'll see that for YYJ and YVR the ATIS is 20 degrees different from the METAR, so it is definitely magnetic.

Perhaps your friend meant "we read it off the METAR and subtract the variation".

I'm not sure about that. When I brought this up it seemed to stir up a discussion in a couple of towers out east, one of them being a major tower.

[FAD3C]

If you call 1-877-517-2847 you can compare the ATIS to the METAR. You'll see that for YYJ and YVR the ATIS is 20 degrees different from the METAR, so it is definitely magnetic.

Perhaps your friend meant "we read it off the METAR and subtract the variation".

I'm not sure about that. When I brought this up it seemed to stir up a discussion in a couple of towers out east, one of them being a major tower.

[Fly The Wing]

If you call 1-877-517-2847 you can compare the ATIS to the METAR. You'll see that for YYJ and YVR the ATIS is 20 degrees different from the METAR, so it is definitely magnetic.

Perhaps your friend meant "we read it off the METAR and subtract the variation".

Variation east, magnetic least (less than true)
variation west magnetic best (better than...more than true)

Ahh from the ground up.

[trampbike]

As ThatArmyGuy said, if your read it, it's true. If you hear it, it's magnetic.
ATIS is in magnetic.

[Heliian]

Same as your runway heading, which is magnetic. It would be pretty confusing otherwise.

[PostmasterGeneral]

As ThatArmyGuy said, if your read it, it's true. If you hear it, it's magnetic.
ATIS is in magnetic.

But what if you read an ATIS off of an ACARS printout??

Hahaha

[FAD3C]

As ThatArmyGuy said, if your read it, it's true. If you hear it, it's magnetic.
ATIS is in magnetic.

But what if you read an ATIS off of an ACARS printout??

Hahaha

I had a tower controller tell me they just read off the METAR and put those winds into the ATIS.

[photofly]

This is one of the best trolls I've read for a while. Keep it up.

[FAD3C]

This is one of the best trolls I've read for a while. Keep it up.

Not interested in this turning into a troll run. Just wanted some clarifications as it's nowhere to be found in the AIM or Navcan's AWS Guide. Hence the Pop Quiz.

[photofly]

It turns into trolling when you "discover" that some control towers in Canada are "doing it wrong".

[CpnCrunch]

It turns into trolling when you "discover" that some control towers in Canada are "doing it wrong".

And it's pretty trivial to prove or disprove. I just disproved it above (at least for the west coast). If the OP has a specific airport in mind, why not take the 30 seconds required to actually check the METAR against the ATIS?

This is just a not-very-interesting piece of rumour at the moment.

[Jack Klumpus]

I can guarantee that the ATIS in YYZ when it was manually done, was read from the METAR.

ATIS winds should be Magnetic.

[Heliian]

I can guarantee that the ATIS in YYZ when it was manually done, was read from the METAR.

ATIS winds should be Magnetic.

Do they not have a wind direction indicator? How far north do you go before it really starts to get messed up?

[Jean-Pierre]

Any proof of that Jack Klumpus? I think YYZ Tower open them self up to legal liability if they had been advising flights the wind ~10 degrees different than what they are.

[tower controller]

The weather on the ATIS is the current METAR and the winds are directly from the METAR. I have never put the winds in as read off the wind instruments the format of the ATIS doesn't allow it.

The METAR is automatically loaded into the ATIS most of the time without any operator intervention.

[cncpc]

This is one of the best trolls I've read for a while. Keep it up.

Way to show your ass.