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skywerd
2nd May 2006, 14:57
Departing Atlanta on runway 26L:
For those unfamiliar, Atlanta has 4 parallel runways. In this particular configuration, departures depart runway 27R and 26L and arrive on 26R and 27L.
Anyway: Departing 26L on the RNAV departure with a strong crosswind from the south. Standard Instrument Departure reads: "Maintain 272 degree heading until 500 feet, thence..."
At rotation, aircraft turns 3 degrees to the south to maintain runway track. ATC experts: Am I to correct the heading to 272 degrees, or maintain the runway track until 500 feet? Given the close proximity to the aircraft that departed 27R right next to me, I see this as somewhat critical. Incidentally, it looked to me like he was on a 272 track, not heading...
Thanks for your input,
Skywerd

Gonzo
2nd May 2006, 15:03
Interesting that the procedure doesn't use 'track'. The departure procedures I'm most familiar with all use 'track', so one might infer then that the use of 'heading' means exactly that; do not take into account the wind. But then I'm speaking here as a layman in terms of US SID procedures.

Mr. Voigt, you there?

Spitoon
2nd May 2006, 15:33
Sadly even those who should know better - and I mean them that write the rules - sometimes can't work out the difference!!!

As I see it, heading means heading, and track means track. And I use the terms in that manner. In some ways it's unfortunate but in most wind conditions it won't make much difference whether pilots or controllers use the terms interchangeably - which just further compounds the problem if they actually mean one or the other.

Lock n' Load
2nd May 2006, 15:41
The Canadian SIDS with which I'm familiar all use runway heading, NOT track.
I would do what the departure plate says, not what I think it should say! Fly the heading.

cossack
2nd May 2006, 15:56
Here at YYZ the SIDs are all headings. When we simultaneously depart parallel runways, we are very aware of drift issues and will correct them accordingly and issue a different heading to fly to ensure divergence.

If in ATL another heading was not issued, then the drift was not sufficient for it to cause a problem. Still you should fly headings if that's what the procedure says to do. I'm not familiar with RNAV SIDs but it would seem a little odd to let an aircraft drift rather than be locked on track to the next waypoint.

Scott Voigt
2nd May 2006, 17:05
Hi Skywerd;

You use heading sir... We would love to use track on everyone, but then not all FMS's are created equal, and they have to dumb down the procedure so that everyone can use it. There are also those folks who can't fly the RNAV procedures, so heading takes care of that... We do the same thing at DFW too...

regards

Scott

skywerd
2nd May 2006, 20:50
Thanks for the great answers guys, especially yours, Scott. Thanks also for the input regarding YYZ. I believe this issue is clearly spelled out on the plates for YYZ, but then again, so are directions to the lav, the canteen and the parking area for undersized tugs :) .
And btw, I really miss working with you guys at DFW. We had quite a presence there at one time ...