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Comment by ceejayoz | Hacker News Reader

> people inbound not ready for this can run out of fuel

Shouldn't you always be ready for a GPS (or other instrument) failure?

Instrument failures are rare and might impact a handful of aircraft; GPS jamming impacts every aircraft in the vicinity. ATC might have capacity to plan low fuel-consumption flight heading paths for a small number of aircraft, but not 100%?

ATC / radio failures happen. If ATC can't plan a route for you, you're still the pilot in command and responsible for finding a diversion airport and getting down safely, and for having had enough fuel to deal with traffic while doing so.

Sure -- I don't think the concern is literally falling out of the sky, so much as having to divert to another airport that isn't being jammed (inconvenient). But we're speculating on the basis of a vague complaint.

Would you be ok with a commercial passenger flight operating with 1 of the 2 engines completely disabled? It's technically designed to fly with 1 engine, so what's the problem?

Knocking out a pilot's GPS gives them one less tool in the event that other instruments fail. It's like saying "shouldn't you always be ready for backup hydraulics to fail?". Taking a backup system offline isn't an ideal situation.

> Would you be ok with a commercial passenger flight operating with 1 of the 2 engines completely disabled?

Yes. They are designed for that, and have procedures in place for when it happens, just as they do for a GPS failure.

(Specifically: https://en.wikipedia.org/wiki/ETOPS)

I would not be OK with a pilot who didn’t plan for the possibility of engine failure.

If you run out of fuel because your GPS is jammed, there’s a good chance you’d have run out of fuel if it failed in another more normal fashion.

You miss the point entirely. No commercial aircraft is going to be allowed to take off with only 1/2 engines in operation. If one goes out in flight they'll usually find a place to land bc it's understood that if that last engine dies then that's a bad situation. Which is the entire reason they have backups in the first place.

I'm not arguing about whether it's possible, I'm arguing whether it's smart. Airplanes have backups, and yes they can run on those backups, or else what would even be the point of having them? This kind of goes without saying...

If planes are DESIGNED to have backup systems, in case there is a failure, then do you think it's smart to arbitrarily remove one of said backup systems?

> No commercial aircraft is going to be allowed to take off with only 1/2 engines in operation.

That's a different question.

If you're knowingly flying into GPS jamming - these jamming operations are apparently announced via NOTAMs (https://news.ycombinator.com/item?id=28833002) - you should be planning ahead even more.

A pilot is responsible for having enough fuel in case of an emergency, like the GPS unit crapping out. Anyone running out of fuel due to GPS jamming was ill prepared for other emergencies.

Lol, I'm not saying pilots CAN'T operate without GPS (I fly hang gliders and I used to fly with literally no instruments at all).

Think of it this way. A person can live a normal life with 1 arm, 1 leg or even 1 eye or ear. Is it ideal? Probably not. If you lose your other arm, leg, eye/ear it's going to cause many more problems than just losing 1.

Losing any backups in aviation is a less-than-ideal situation. That was the only point I was trying to make. OF COURSE pilots can operate a plane without GPS, my god I'd hope they could. I feel like that kind of goes without saying.

You’re making a lot of specious arguments. I think your laymen’s logic checks out just fine here but that’s not how aviation works…and for good reason.

Taking off with 1 of 2 engines is a lot different than taking off with inoperative avionics. The FAA and airlines dictate what minimum equipment is required for any given aircraft to be airworthy and it’s a fairly robust document that takes into account myriad situations and flight conditions.

Yes that's even part of the verbal/written test. You have to calculate fuel requirements to different distances and they give you options that would be technically right but check to see if you pick the conservative approach in the event of this very situation. If you want to see how many people toss that knowledge out the window listen to some of the videos at VASAvation [1] and instead choose to land on freeways, city streets, farm fields, etc... Not all of them are due to fuel, but some are.

[1] - https://www.youtube.com/c/VASAviation/videos

Yes and especially because planned GPS jams are published in NOTAMS, in my experience, well in advance of the event. Ignorance isn’t really an excuse.

Of course you should be prepared for accidents, but it's quite another to be so prepared accidents don't turn into emergencies.

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