David Megginson wrote: > Major A writes: > > > - The autopilot in the 172 tries to keep the orange heading bug at the > > > top of the directional gyro, period. If you set the DG to the true > > > heading (as you would in the Arctic), then the autopilot uses true > > > > Ever flown a (real) 172 across the North Pole? :-) > > No, but the Arctic starts a long way from the North Pole. Many people > in Canada fly 172's in Northern Domestic Airspace (roughly north of > 60, but it zigzags a lot), where you use true rather than magentic > headings. The same may apply to parts of Alaska.
It's worth pointing out that a DG will work fine in the polar regions. Other than precession (which has a 24 hour period -- hardly a huge source of error), there's no way for it to "know" that it's over the pole. It will even work fine on the pole itself, in the sense that it will always point toward the same meridian. It won't tumble or do anything silly. Only floating point euler angle computations have trouble at the poles; real hardware is a little more robust. :) Andy -- Andrew J. Ross NextBus Information Systems Senior Software Engineer Emeryville, CA [EMAIL PROTECTED] http://www.nextbus.com "Men go crazy in conflagrations. They only get better one by one." - Sting (misquoted) _______________________________________________ Flightgear-devel mailing list [EMAIL PROTECTED] http://mail.flightgear.org/mailman/listinfo/flightgear-devel
