If you wanted an approximation, start with a guess. look 50 miles
along that course line, note the deviation and variation at that point
and use it to calculate where you'd be for a 100 mile flight. Repeat
from that point about 30 times until you are abeam SFO. Now, since
that's about a 3000 mile trip, adjust your initial guess by 1 degree
for every 50 miles you're off, then try again. We used to call that
approach a numerical solution, or brute strength calculation, it
probably has a sexier name now.

There's a neat implication here. If you want to arrive within say 10
miles of your target after holding constant heading for 3000, your
heading has to really really be constant -- like to the tune of arc
tan (10/3000) or 0.2 degrees. That's a really tight tolerance to hold
on average.

Remember Linburgh arriving over Ireland within a few miles of where he
intended, after crossing the ocean? Lucky Lindy indeed!



going On Mar 4, 1:00 pm, "Jon Woellhaf"
wrote:
It's not really a trick question, but I think it's a difficult one.

"M" wrote in message

oups.com...



On Mar 3, 3:18 pm, "Jon Woellhaf" wrote:

What fixed compass heading would hold to fly from JFK to SFO (assuming no
wind correction)?

Is it a trick math question? It's certain won't be the great circle
route, which has a continuous changing magnetic heading to hold.

Given the difference of magnetic variation between west coast and the
east coast, I'm not certain this can be calculated using a math
formula. Such a magnetic heading can be deduced by a computer
simulation using the brute force method.- Hide quoted text -

- Show quoted text -