Comment by jjwiseman | Hacker News Reader

Comment by jjwiseman | Hacker News Reader

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There usually are other systems (e.g. ILS), but not always.

This post has several comments along the lines of "We used to fly without GPS and it was fine!" The fact is that aviation is so much safer than it used to be, and GPS is part of that. GPS helps aircraft navigate accurately even when they're not near an airport. It helps give situational awareness and avoid mid-air collisions (almost every aircraft these days has a traffic display that shows ADS-B positions of other nearby aircraft, and those positions come from accurate GPS).

Loss or spoofing of GPS isn't usually a critical safety issue on an aircraft, but it definitely removes layers of safety and adds additional risk. Pilots can lose that situational awareness of nearby traffic. They may have increased workload and distraction due to having to use a less familiar & less accurate means of navigation, trying to figure out why their systems aren't working correctly, and even getting bogus ground proximity warning system alerts. ATC may now have increased workload and distraction because some approaches or even runways are no longer usable.

We drove cars for a long time without seat belts and air bags, too.

> We drove cars for a long time without seat belts and air bags, too.

And if we were having problems with seatbelt jammers, everyone would instantly respond by just not using seatbelts in those areas. There would be no road closures and no trip cancellations. What are we supposed to learn from this analogy?

That aviation without GPS isn’t as safe as aviation with it.

I don't even think that's true. Seatbelts are an improvement in safety regardless of context. But what you're arguing here is that a system that's designed to rely on GPS availability, and gets it, is safer than the same system during a GPS outage, not that GPS availability will make any airport management system safer.

It makes it safer to run aircraft closer together. Most airport capacity increases these days come from optimizing airspace, not from new runways or airports, which are time consuming, expensive, and controversial. We used to operate without them but we were also generally operating a lot fewer flights back then.

The more apt analogy is what would our roads look like if all traffic signals stopped working? People would still drive, but it would have to be at lower speeds, with more congestion, etc.

> The more apt analogy is what would our roads look like if all traffic signals stopped working? People would still drive, but it would have to be at lower speeds, with more congestion, etc.

This happens pretty frequently with single signals, so we know what that looks like.

An unattended broken signal gets treated like a stop sign (by law), and this immediately blocks traffic. It's a total disaster.

If it happens anywhere near a population center, a human will be dispatched to cover for the broken signal and dysfunctional law by manually directing traffic, and this gets you almost all the way back to normal.

If every signal failed at once, that would cause much bigger problems, but in the event that we know we're unable to repair the signals, which is the case here, we wouldn't just try to muddle through using the existing roads and systems. We'd define new systems that worked better in the absence of traffic lights.

I was mostly addressing the idea expressed in other places in this thread that aviation without GPS is fine, not your specific point. To address your question, the commercial aviation world is still in the process of figuring out how to deal with the new, current reality of GPS jamming and spoofing. They're developing new procedures, designing new equipment, and changing priorities and plans. While this happens they're downplaying the risks in press releases and statements to avoid spooking the public.

"If this is a regular thing, shouldn't we have ways of using the airport without hoping that the jamming is having an off day?" Yes. But it takes time and money. This level of GPS interference is relatively new, and for about the past 30 years you could basically assume GPS would be available.

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