There seems to be no Mag Track printed out on the PLOGs - just True Track and a wind derived Mag Heading. As Mag Track is the primary course information used by all the aircraft nav instruments, may I ask why it has been omitted? The only way at present to derive the Mag Track is to create a PLOG with a zero wind component.





neutron

are you sure



i planed a route from Thame (near EGTB) to Long Crendon.

The Track is 000 Deg and the Heading (M) is 2 Deg.



Adding a wind 270/90 the Heading (M) is 272 Deg, which seems right to me

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Galaxy Tab Plus 7 inch, NavsGo GO7100 as of March11

Magnetic track is a fairly pointless piece of information, and isn't one we've ever heard a request for in the PLOG. What instrument in particular do you have that wants to know magnetic track?

I deleted your last post as it appeared only to call into question the aviation experience of the SkyDemon staff and not to contribute anything to this discussion.

Let me frame my last statement in the context of "for a piece of flight-planning software". The reason why pretty much every feature of SkyDemon is the way it is, is because of either customer feedback or prioritisation of features. So far we've had a grand total of one person ask for magnetic track to be displayed on the PLOG. There would be no surer way to ensure the eventual failure of the SkyDemon product than to implement every feature that every person asks for, so we operate based on consensus.

1. SkyDemon does not feature full vertical navigation facilities. This topic has been addressed elsewhere in this forum and the basic answer is "they will come when there is sufficient demand".

2. You are expected to work in TAS in SkyDemon; it's unclear what the "etc" in your point refers to. Again, we have a great deal of customers but none of them have so far expressed a desire to operate in IAS when planning a route.

3. If you believe some of the areas of Scotland in which we have designated FIS frequencies are incorrect, or the frequencies themselves are incorrect, tell us which ones and we will investigate. I do not recall receiving a report from you about this.

4. There is little we can do about this at this point in time.

5. Probably the coastline, which in some areas can be off by as much as 1nm but in most areas is accurate. Again, if you find that a town appears to have the incorrect coordinates, let us know about it.

I received a PM from Anonymous with some points about magnetic track which, since the sender was Anonymous, I couldn't repond to so I'll do so on here. Please bear in mind I'm not trying to say that anyone is wrong, but trying to provoke significant justification such that we can make a case to change or enhance the software.

> The reference instrument for all aircraft flying today is still the magnetic compass.
Yes. However once airborne the compass will not read the same as the potential mag track column unless there is nil crosswind. I'm afraid I therefore don't understand the relevancy of this statement.

> It is the magnetic track ... that is entered into ... built-in IFR GPS's.
This is pretty compelling. When would you enter an actual track (whether it's true or magnetic) rather than simply entering the waypoints?

> All runway headings are in degrees magnetic as are all bearings derived from VORs.
Yes, but it is unclear how having SkyDemon output legs as magnetic bearings is relevant to runway headings. Could you explain how bearings derived from VORs relate to one's PLOG, unless you are actually tracking along a radial?

> All bearings on airfield plates are in dregrees magnetic.
Agreed. However the PLOG shows enroute legs only; could you explain how the potential mag track column will be used to relate to the magnetic bearings shown on airfield plates?

> How is SkyDemon applying magnetic variation, which varies from place to place?
SkyDemon uses the standard magnetic model of the earth to calculate the exact magnetic declination at the midpoint of each leg, on the day the flight is planned. If you think SkyDemon's value for magnetic declination at a specific point is wrong, please let us know the position and what you think it should be.

I sent you the pm. For some reason, the forum allows you to post pms without being logged in. The full text of my pm is below:

The reference instrument for all aircraft flying today is still the magnetic compass and therefor once you are in an aircraft all tracks, headings, brearings and vectors are given in degrees magnetic. It is the magnetic track not the true track that is entered into all the aircraft's navigation instruments including built-in IFR GPSs. All runway headings are in degrees magnetic as are all bearings derived from VORs. All bearings on airfield plates are in dregrees magnetic. It is the true track that is irrelevent!

 

How is SkyDemon applying magnetic variation, which varies from place to place? I have a suspicion that the derived mag headings which with zero wind should be the same as mag track are some degrees out for tracks in my local area.

 

My point is that at present, all headings, tracks, radials, intercepts and radio navigation is carried out in the aircraft using magnetic bearings hence the importance of including mag track in the PLOG. It is mag track you set in HSI or CDI. It is the mag track from waypoint to waypoint that is displayed on IFR GPS sets. True track is not used other than to plot one's course on a chart which is then converted to mag track for navigation purposes.





neutron

Would you mind responding to the points I raised?

SkyDemon is software targetted at pilots who will be flying VFR and it sounds rather like the justifications you're using are based on navigation either with an IFR GPS or by tracking from VOR to VOR. This is of course perfectly valid, but the majority of our customers appear to navigate either with a VFR handheld GPS or with a VFR chart. Radio aids are often used of course, to confirm position, but do not necessarily comprise the route itself so having something to "dial in" to the HSI wouldn't be required.

Again, I stress that this is merely our experience of customer feedback and this is what drives which features make it into the product. Perhaps we'll get lots of (unsolicited) input in this thread from people who'd like to see an option for mag track added to the PLOG. In which case - we'll add it!

OK

To reply to your questions:

> The reference instrument for all aircraft flying today is still the magnetic compass.
Yes. However once airborne the compass will not read the same as the potential mag track column unless there is nil crosswind. I'm afraid I therefore don't understand the relevancy of this statement.

The relevence of this is that all in-flight bearings should be derived from the same datum and magnetic is the one used universally. The CDIs on your nav instruments whether they be traditional steam VOR indicators or GPS driven CDIs need to be set to the MAGNETIC Track you intend to follow. The offset wind derived magnetic heading is the heading you fly to achieve the selected Magnetic Track

> It is the magnetic track ... that is entered into ... built-in IFR GPS's.
This is pretty compelling. When would you enter an actual track (whether it's true or magnetic) rather than simply entering the waypoints?

You would normally enter waypoints but you might well enter a magnetic track to fly on the HSI page of your GPS. Certainly your GPS should display the Magnetic Track to the next waypoint which should agree with the Magnetic track you have dialled into your CDI instruments.

> All runway headings are in degrees magnetic as are all bearings derived from VORs.
Yes, but it is unclear how having SkyDemon output legs as magnetic bearings is relevant to runway headings. Could you explain how bearings derived from VORs relate to one's PLOG, unless you are actually tracking along a radial?

It's not just bearings derived from VORs and you don't need to be tracking a VOR radial - any course you set in a CDI instrument needs to be set as a Magnetic Track. A CDI type panel mounted GPS Indicator as well as a VOR indicator (which may be operating in RNAV mode with a pseudo-VOR displaced onto the waypoint) needs to be set up with the Mag Track to the waypoint so you need that information on the PLOG.

> All bearings on airfield plates are in degrees magnetic.
Agreed. However the PLOG shows enroute legs only; could you explain how the potential mag track column will be used to relate to the magnetic bearings shown on airfield plates?

It doesn't but that's hardly the point. The real thrust of my argument is that you need to stick to one datum - magnetic.

 

Hope this helps.





neutron

Thanks Neutron. Hopefully we'll get more input on this now there's a suitable thread for it.

hi I agree that the Mag Track is important. Although you fly compass headings but in order to calculate those you need the magnetic headings first of all.

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Galaxy Tab Plus 7 inch, NavsGo GO7100 as of March11

I think the problem is that when training for your PPL you are taught - draw the line on the chart (True Brg), apply wind correction (True Brg), apply mag variation/compass deviation to get Mag Heading and that's what you fly.

Once you start flying, all that goes out of the window and most pilots fly using some form of radio navigation, be that VORs, NDBs or most usually now GPS. For all of these the standard convention is to fly Mag not True so it's the Mag Track between beacons/waypoints that you need. We're lucky in the UK, our magnetic variation is in the low single digits, typically around 3-5 degrees so the difference between True and Mag is not that great. There are places where it's well over 30 degrees different and they still use Mag Tracks for Nav.





neutron

Are you saying that on all the handheld VFR GPS units that our customers are using, the track being displayed is magnetic and they are not just outputting the true track as received directly from the GPS chipset?

I would guess that the answer to that question is yes. Certainly my aviation GPSs, both fitted and portable  use Mag as default.

Perhaps it would be useful to ask the question on the Flyer forum?





neutron

I'd say it would certainly be useful

Hi Tim,



I would certainly utilise a magnetic track column in the PLOG because although I am a VFR pilot, I often navigate through use of VORs especially around the London area. The magnetic track (radial) to or from VORs would be useful in order to tune the VOR radial and provide a backup to my GPS device running SkyDemon. At the moment when navigating through use of VORs, I either have to manually apply the magnetic variation to the true track or produce a PLOG with no wind.



Regards,



Richard Avery

We've added mag track as an option (off by default) in the PLOG ready for the forthcoming beta release of the 1.4 version. We will await feedback on it and hopefully those who have requested it will find it useful!

A further example of the need for Mag Track - 

Quadrantal Rule - cruisings levels are selected in accordance with the Mag Track, these levels are mandatory for IFR but highly recommended for VFR. To select an appropiate level at the planning stage, the Mag Track also needs to be listed under leg properties and appear at the bottom of the screen if a leg is highlighted.





neutron

Here's me two-pennyworth for what thats worth.

1. I am a VFR flyer use map, compass & hand held GPS 296 & Skydemon. No radio navigation equipment.

2. I am certain the GPS is NOT showing magnetic track. I frequently see a major difference in the GPS readout and the compass (I have 2 one of which is digital and has the appropriate magnetic sensors).

3. While I have never used Mag Track for anything (except during TopNav pre-flight planning using VORs), I can accept that others may well need them. I assume they will not use the inflight verison of SD. Also I notice that both Navbox and PocketFMS both ouput Mag Track in their logs  .. PFMS at least is much used by GA crowd.

4. There is no doubt that there is room to include this on the log printout.

David

Pink Leader

You can be pretty sure that your Garmin GPS is displaying Mag Track. The give-away is the small 'M' appended to the heading figure. If you force the GPS into true mode the heading will be appended with a 'T'.





neutron

bashope, this thread was ten years old.

I found this thread via google search

Mike
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