Polar Grids Q

[Cron]

Would appreciate some guidance with the solution of this Q. I have not included values as the Q is from an FTO and may be copyright.

A Northern L.C.C is overprinted with false grid. Constant of cone of chart is A.

At B degrees West the grid track is C and the true track D.

At which longitude is the false grid aligned?

Thanks

[oxford blue]

Comparing C and D will give you the chart convergence, and also whether E or W.

On a Lamberts chart, convergence = change of longitude (from the datum) x sin of parallel of origin (or 'n' factor).

Therefore, change of longitude = chart convergence/'n'

That change of longitude is the difference between B and the datum.

You now have to work out which sense to apply it . In the N hemisphere, if convergence is W, B is E of the datum. In the S hemisphere, if convergence is W, B is W of the datum.

Can't you ask the instructors at your FTO?