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That doesn't make sense since most GPS units also include an altimeter. Plus, you can get an inaccurate altitude estimate from GPS itself. I suppose it's possi
by brndnmtthws 9y ago
That doesn't make sense since most GPS units also include an altimeter. Plus, you can get an inaccurate altitude estimate from GPS itself.
I suppose it's possible that the unit doesn't include an altimeter or doesn't account for altitude, but that seems odd.
- mikeash 9y agoWhoever wrote the "am I parked?" code probably didn't think to check altitude, since when could an airplane possibly be moving vertically but not horizontally? A lot of these units are built for powered aircraft and then appropriated for gliders. I'm confident that software written with gliders in mind would not have this problem.
- ilovecaching 9y agoActually this is quite possible in a light aircraft. If you're flying into a fast wind, you can maintain lift while also not generating enough thrust to negate the speed of the wind, leaving you hovering over a spot, or moving backwards.
- mikeash 9y agoObviously, but how often do they actually do that?
- lb1lf 9y agoI once sat in a commercial aircraft (only barely - a Do228!) which, landing straight into the wind, appeared to stand still and just touch down vertically. Now, I know that this is impossible (no way the stall speed, even with full flaps, sensible AoA and near empty plane is lower than the wind speed at which the airport closes!) - but it definitely felt and looked as we simply gently dropped out of the sky, helicopter style. The pilot suggested this was not uncommon practice when I asked him after we'd parked on the apron - fast, steady wind was what they encountered every day landing on these northern Norwegian islands.
- bitwize 9y agoFairly often, given a light enough aircraft and strong enough winds. My grandfather used to like to tell the story of flying backwards (over ground) in a Luscombe 8A or 8B.
- rubidium 9y agoHelicopters?
- mikeash 9y agoNot their target market.
- deleted 9y ago[deleted]
- mxfh 9y agoMore likely the sensor data is all there, but the high level routine only checks for variation in latitude and longitude.
- moftz 9y agoIt seems like a GPS meant to go on an aircraft would support checking all degrees of direction before deciding to turn off or just not turn off at all since having an aircraft turn off any of its navigational aids seems really dumb. It sounds like he's using just a typical handheld GPS or one meant for a car instead of a real aircraft version.
- mikeash 9y agoThere are cheap handheld aviation units that are not meant to be relied upon in any way, but just help out when able. You're never supposed to put yourself in a situation where losing them would create any safety risk. GPS units that you actually rely on are built to a totally different standard (and price).
- ryanisnan 9y agoHave you ever used a field GPS device? They are riddled with oddities and bad UX decisions.