True Or Mag?

[PODKNOCKER]

To enable Air Canada to climb through our level, we were asked what our heading was...096 between Gander and 50 West...Air Canada told to head 096 and cleared to climb through our level to be level by 50 West. He crossed our nose three miles ahead and 200 feet above. ATC asked if he was heading 096. He was, but in TRUE and we were magnetic. Asked other carriers what they flew across the pond and there seemed to be a 50/50 split.
What do YOU fly across the pond, TRUE or MAG?

[Captain Stable]

At what latitude was this?

[mattpilot]

When ATC gives headings, isn't Magnetic always supposed to be used?

[ETOPS]

When flying in the North Atlantic track structure and in MNPS airspace you should select "True".

As you were between Gander and 50W you were under radar control so should have had "Magnetic" selected and thus been able to comply with ATC instructions and seperation.

[PODKNOCKER]

ETOPS...thats my whole point...if you look at the poll you will see that more operators are MAG than TRUE across the Atlantic. If you can tell us where it is cast in stone that we should all be in TRUE then we could get everyone flying same way same day. I have been flying the Atlantic for 30 years with five operators and have always been in magnetic.

[ORAC]

It would appear that it's not cast in stone. North Atlantic routes are defined in navigational coordinates only. The decision whether to navigate between them in True or Magnetic is the operator's.

North Atlantic MNPS Airspace: (In particular, page 46 and 52/53).

MNPS Airspace (ftp://www.nuntius.co.uk/nat/MNPSA9/mnps9.pdf)

[DrSyn]

In POD's original, specific case, under Gander Radar, the answer is unequivocably Mag. I also agree with ORAC's observation that it is up to the operator to specify company procs for NAT MNPS ops. It is not a requirement to operate OTS in True.

To save some poor soul from downloading and then wading through the entire MNPSA Doc, fascinating as it may be, here is the relevant extract on the subject:
___________________________________________

Avoiding Confusion between Magnetic and True Track Reference

To cover all navigation requirements, some airlines produce flight plans giving both magnetic and true
tracks. However, especially if crews are changing to a new system, there is a risk that at some stage
(e.g. during partial system failure, reclearances, etc.), confusion may arise in selecting the correct
values. Operators should therefore devise procedures which will reduce this risk, as well as ensuring
that the subject is covered during training.

Crews who decide to check or update their LRNSs by reference to VORs should remember that in the
Canadian Northern Domestic Airspace these may be oriented with reference to true north, rather than
magnetic north.

Navigation in the Area of Compass Unreliability

In areas of compass unreliability basic inertial navigation requires no special procedures but most
operators feel it is desirable to retain an independent heading reference in case of system failure.

Different manufacturers may offer their own solutions to the special problems existing in areas of
compass unreliability. Such solutions should not however involve the use of charts and manual
measurement of direction.
________________________________________________

Hope this helps.

[Intruder]

AFAIK, True headings/tracks are used only in the designated Area of Magnetic Unreliability and the Northern Canada area (where it is clearly marked on the charts).

[reynoldsno1]

In Antarctic regions, grid gyro is used (i.e. slaved compass systems are isolated from the magnetic detection unit).

There has been a long debate in ICAO about the mag/true question - it still has not been resolved. Most GA aircraft do not have the required level of sophistication in their heading reference systems to operate in true.

[PODKNOCKER]

More votes please...so far the mags have it, but there needs to be a larger response to get a valid arguement either way.