15 ms·
Before the days of GPS in the cockpit, a relative of mine was a 747 captain doing routes across the Pacific. On one flight, all of the gyros went offline. He
by tomohawk 8y ago
Before the days of GPS in the cockpit, a relative of mine was a 747 captain doing routes across the Pacific. On one flight, all of the gyros went offline.
He had been trained in the US Air Force in celestial navigation, so he was able to use that to get the aircraft within range of a beacon, and land safely.
- gcb0 8y agowouldn't a simple compass have sufficed if they weren't off route?
- dproblem 8y agoInverting compass readings into position is highly problematic because of interference, and noise.
- gonzo41 8y agoThere'd probably be too much metal / electrical interference for a regular compass to work.
- gruez 8y agoPlanes don’t have built in compasses? edit: yes they do https://en.wikipedia.org/wiki/Flight_instruments https://en.wikipedia.org/wiki/Flight_instruments
- danaliv 8y agoAirplane compasses are indeed affected by the electrical system, but not so much as to make them unusable. A maintenance process known colloquially as "swinging the compass" involves turning on the electronics, positioning the aircraft over a compass rose painted on the ground, and noting the error at various bearings. As for the metal, most metal airframes are aluminum.
- hermitdev 8y agoA compass would probably be of marginal utility if you're flying a "great circle" route across an ocean. For instance, if you were to fly non-stop from Chicago to London, your initial route will have you heading north east, but at the end, you'll be heading south east.
- HarryHirsch 8y agoThat's why ships would follow a loxodrome instead of a great circle route. They'd still arrive in port, though.
- mjlee 8y agoWhile this is true, an aircraft has very critical fuel requirements - taking a longer and less efficient route combined with a faulty navigation system is a factor best avoided.
- ninkendo 8y agoI was about to correct you sand say "no, they'd follow a rhumb line", but then I looked it up and realized they're two terms for the same thing. TIL!
- danaliv 8y agoAll airplanes (or almost all? I'm sure someone will know of an exception) have compasses. But without data on wind direction and speed, a compass isn't much good over any appreciable distance. Once off the ground, an airplane is like a boat crossing a swift river. The boat won't land where it's pointed; it'll move with the current as it crosses and end up landing downstream of where it's pointed. So it is with airplanes. They don't fly where they're pointed; they move with the wind as they fly.
- darkpuma 8y agoBoeing 707s were equipped with sextant periscopes. It's popular belief that 737s used to be as well, though I believe that was only the case for a handful of 737s purpose built for the USAF.