HP 15CE Aviation Pac

[Geoff Quickfall]

I will dig it up, it is storage after renovating the cave! I seem to remember that it was a navigation book using programable calculators.

This particular program using the polar / rectangular functions was for the HP 25. It used the same amount of memory as the standard sin / cos routine but was an interesting math solution.

On the 41C I would put a test in to determine if the longitude of point a was equal to the longitude of point b, therefore due north or south, then a second subroutine to determine if point a longitude was > than point b for direction of flight.

Another to determine if you were traversing through a pole.

Which raises an interesting point on the GPS navigation used on the Flight Management Computers that Boeing used. I am sure this applies to Airbus FMAs. The flight cannot proceed within 90 nautical miles of true north or true south.

Having flown over the north pole a few times it was interesting to see the dogleg around the north pole on the flight plan. This occurred with GPS, INS and IRS navigation from latitude / longitude waypoints.

Cheers