14
votes
Accepted
Why does this chart seem to show airports with magnetic variation up to 90 degrees?
How do you think "the figure seems to show an extreme variation of up to 90 degrees"?
I don't think you're understanding that diagram correctly.
There is nothing close to a variation of 90° ...
- 30.4k
12
votes
Why does this chart seem to show airports with magnetic variation up to 90 degrees?
Take a closer look at the map. The contour lines show the places where the magnetic deviation is the same. The green lines specifically show where the deviation is zero, so in Indonesia the deviation ...
- 121
11
votes
Why is the treatment of magnetic variation different for NDB and VOR?
The reason is, that for a VOR, the receiver in the aircraft determines the radial based on calculating the phase shift and as the VOR is oriented to the magnetic north of its location, we need the ...
- 271
9
votes
Why does this chart seem to show airports with magnetic variation up to 90 degrees?
The lines in your plot indicate paths along which the magnetic deviation is constant.
If one plots the direction of north as displayed by a magnetic compass, one gets the blue arrows in the following ...
- 7,227
8
votes
Accepted
Do large cities contain enough iron to significantly affect an aircraft's magnetic compass?
A single steel building does, if the aircraft flies close enough, never mind a city core like those of New York or Chicago.
However, the amount of steel isn't the whole story. Each I-beam, sheet of ...
- 17k
7
votes
Do large cities contain enough iron to significantly affect an aircraft's magnetic compass?
The short answer is no, at least not to an extent that is noticeable or requires pilot compensation to deal with.
On the deck of an aircraft carrier with orders of magnitude more steel and signal ...
- 24.9k
7
votes
Accepted
What official government document should a pilot check to determine what magnetic north a VOR was set to when it was commissioned?
The chart supplement does list the magnetic variation of the VORs. Looking under the "radio aids to navigation" section for a nearby airport, it's listed at the end of the line, right after the ...
- 71.8k
7
votes
Accepted
Why do both east and west isogonic lines tilt toward the west as they go north?
Because the present position of the magnetic pole pole is such, that in central and eastern US states the isogonic lines are tilted to the West. But in western parts of the U.S., those lines are ...
- 11k
6
votes
Accepted
Is my understanding of magnetic variation and declination (for a VOR) correct?
Since the magnetic variation is +0.27°, the "zero bearing" is equally +0.27° east of true north and therefore the (undeclared) valDeclination must be +0.27° as well.
You are assuming that the VOR ...
- 3,751
5
votes
Why does Garmin Pilot tell me a wrong magnetic variation?
Typically, the data is taken from the respective national aviation authority. The FAA has incorrect information for KCNO in its database.
https://www.faa.gov/air_traffic/flight_info/aeronav/aero_data/...
- 12.2k
5
votes
Accepted
Why do METARs report wind relative to true north rather than magnetic?
Metars are used by more groups than just aviation. In the U.S. it is official weather for the National Weather Service. It is easier to graph winds in relation to true north than have them in shown ...
- 12.2k
4
votes
Are artificial magnetic fields used or proposed to be used to shield high altitude pilots and astronauts from charged, high energy radiation?
This won't work.
What to shield
Most of the cosmic radiation has quite low energies and can easily be shielded by the hull of an aircraft, spaceship or spacesuit. This would also be shielded by the ...
- 7,227
4
votes
Why does this chart seem to show airports with magnetic variation up to 90 degrees?
In fact, magnetic variation (often called declination) can be as much as 180°. If you walk from the axial south pole towards the magnetic south pole, or from axial north to magnetic north, your ...
- 141
4
votes
Accepted
Which "North degree" is using on the PFD heading, Jeppesen Charts and Maps? (Headind indicator, MSA, coordinate lines, bearings..) True or Magnetic?
Magnetic North is generally used for a both aircraft navigation displays and chart representations.
Yes, it is correct that "All charts are drawn in reference to true north", but all ...
- 37.5k
3
votes
Accepted
What does the expression (For VOR/ILS/MLS, give VAR) in the table mean? Because VAR (magnetic variation) value is not given in the table
In short: According to ICAO Annex 15, declination should be provided in this column for certain navaids. The mention "give VAR" is part of the template used, and originally found in the ICAO ...
- 71k
3
votes
Accepted
Are the runway directions given in the table relative to magnetic north or true north? (True or Magnetic?)
The answer is these bearings are referenced to true north as indicated in the official AIP for Turkey:
However I don't understand why this reference to true north is not explicitly mentioned in the ...
- 71k
3
votes
Accepted
Which of the arrows in the magnetic variation symbol represents which North value (Magnetic N, True N)?
The chart is always drawn with true north pointing straight up. The magnetic variation is given on the arrow pointing along the local direction of the field lines (not technically towards magnetic ...
- 54.3k
3
votes
Accepted
Is this the correct sequence of steps to convert from true course to compass heading?
Yep, that's how it's done!
(If you fly the same airplane all the time, one other thing you could do is take a photo of the compass card. That way, you have the deviation already handled and you save ...
- 23.1k
3
votes
Where do I land if I fly from KLAX with a constant east heading, crossing the US and the Atlantic ocean?
Finally I'm adding this update to the answer sweber provided years ago, using current magnetic declination at an altitude of 15,000 ft. It shows a larger deviation. It's not the magnetic declination ...
- 71k
2
votes
What course should be taken to make estimated calculations?
I would calculate that leg in two segments. From GIJ to BENJO flying a course of 082 magnetic (50 NM), thence from BENJO to CRL on a magnetic course 087 (79 NM).
In addition, the magnetic variation ...
- 72.8k
2
votes
Accepted
How can I use a magnetic declination chart to calculate true track, magnetic track and magnetic variation?
The chart shows you lines of equal declination $D$. You identify your location on the chart (which you have done and marked with an X in your second image). Then you determine on which line you are. ...
- 54.3k
1
vote
How can I determine the runway number from its true bearing and magnetic variation?
Runways are named after their magnetic headings.
To convert from True to Magnetic, use "East is least (i.e. subtract), West is best (i.e. add)".
If you are standing at this location looking in the ...
- 21.8k
1
vote
Accepted
How do I answer this navigation problem?
QDM is magnetic bearing to station, QDR is magnetic bearing from station so VAR and DEV are here only to confuse you; the QDR is opposite of QDM so the answer is 099.
Notice that QDR and QDM do not ...
- 3,250
1
vote
Is this the correct sequence of steps to convert from true course to compass heading?
For those interested in a formula to directly compute True heading from True course, here it is:
$$T_H =T_C + \mathrm{arcsin}\left(\frac{W_S}{\mathrm{TAS}}\cdot\mathrm{sin}(W_
D-T_C)\right)\tag{1}$$
...
- 700
1
vote
Do I use true or magnetic north in headwind component calculations?
Surface winds, as reported by the tower are magnetic. Runway headings are magnetic. However, METARs are reported true, according to Aviation Weather Services and ICAO. Therefore one has to perform ...
- 17.7k
1
vote
How do I convert true heading to magnetic heading or the other way around?
True
Virgins
Make
Dull
Companions
At
Weddings
That mnemonic device reminds one how how you go from True to Magnetic (compass heading, course, etc).
Take the True heading, apply magnetic Variation to ...
- 11
1
vote
What's the difference between True vs Magnetic headings?
Magnetic heading works with a compass. No need for electricity, no need for a radio, no need for satellites. If you have a failure of any navigation system, or main battery, your compass will tell you ...
- 77
Only top scored, non community-wiki answers of a minimum length are eligible