5 ms·
Imagine you're flying the landing pattern in a cloud. You just flew through a thermal boundary so your battery jostled and lost voltage for a split second, rese
by yellowbkpk 16y ago
Imagine you're flying the landing pattern in a cloud. You just flew through a thermal boundary so your battery jostled and lost voltage for a split second, resetting your electronics that require a >5 minute reboot and config time. How do you determine geographic north?
- DanielBMarkham 16y agoAnd whatever you do, don't forget your manual compass deviation rules: accelerate north, decelerate south Trivia note: I believe the standard compass is called a "whiskey compass". Not sure why. Probably because if that's all the nav gear you got working you'll probably be using copious quantities of whiskey after landing. (Actually if memory serves I believe the early compasses floated in whiskey. No doubt this practice did not last very long. I think they use kerosene now)
- pavel_lishin 16y ago"We wouldn't be lost if Bob here hadn't drank the compass."
- jcl 16y agoThe explanation I have read is that it is a "wet compass" (a ball floating in liquid), which was abbreviated "W compass", which is pronounced "whiskey compass" in the NATO phonetic alphabet that pilots use. I doubt whiskey was ever used to fill them, since even water would have worked better in terms of cost, transparency, evaporation, or boiling point.
- pdx 16y agoI suspect it would have been freezing point that was most important, and whiskey was a readily available source of low freezing point liquid.
- DanielBMarkham 16y agoI've read that as well. Just trying to share a little FBO-lore. It's common to tell the whiskey compass story in the fashion I have. http://iflyasa.com/2009/10/11/whiskey-compass/ http://iflyasa.com/2009/10/11/whiskey-compass/ I was aiming for tone, not accuracy. There are all sorts of topics that pilots discuss with great vim and vigor. I was trying to convey that feeling. Looks like I missed the boat.
- ZoFreX 16y agoI doubt any pilot would forget their grid north / magnetic north conversions. I hope not, anyway. That stuff got drilled into us in the cadets.
- robryan 16y agoIsn't that the same problem though? Easier from them to do one calculation on the ground in advance rather than pilots having to worry about a conversion in the air.
- metageek 16y agoParticularly since the pilot would still have to look up the local conversion, since it varies from place to place.
- borism 16y agothat just means there is a market for ultra-low-power battery-assisted magnetic-to-true-north converters!
- maigret 16y agoICAO VFR maps contain the magnetic deviation as information - you just have to apply it to all your directions and be able to remember in what direction you have to correct ;) Not so trivial under stress. Anyway, on US and EU latitudes, the difference is not much bigger than 2 or 3 degrees, right?
- wtallis 16y agoNo. The magnetic declination can be quite significant even in the continental US, and it isn't determined by latitude alone: http://en.wikipedia.org/wiki/File:IGRF_2000_magnetic_declination.gif http://en.wikipedia.org/wiki/File:IGRF_2000_magnetic_declina...
- jberryman 16y agoTrick question: the correct answer is you eject immediately.