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Comment by seppel | Hacker News Reader

> Your (b) is an especially tendentious phrasing.

Yes, you are right, it was maybe a stupid phrasing, I'm particularly annoyed by it and I should have given a better example (but I disagree that you cannot distinguish tap water from bomb ingredients. Of course you can. And I did even talk about the stupid 100ml limit, which is apparently the threshold you need for bombs. And they will lift the limit soonish, because apparently the counter-terrorists have won).

Anyway, let's take a better example: I'm not allowed to bring weapons in the cabin because they are a safety risk. This is an understandable risk, they will enforce it (not by asking but by searching), and if you still end up with a weapon in the plane and disturb the flight, you will for sure end up in jail.

If your cell phone rings loudly during take off, you will politely be asked to turn it off. If it rings silently, nobody will ever care.

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It makes a bit more sense when you take into account mitigation strategies for each hazard.

- If somebody has a weapon in an aircraft and is intent on using it, it's unsafe, and there's not a whole lot that can be done. You're all trapped in a sealed pressure vessel, and law enforcement isn't coming until you're on the ground. Your only mitigation strategy is to hope the crew and passengers can fend for themselves.

- If you lose ground-based navigation during landing, it's unsafe, but there are several mitigation strategies. You're not going to land at that moment anymore, but the pilot can abort the landing, switch over to GPS, and fly the missed approach to get back up to altitude. At this point there's time to troubleshoot... They can make an announcement asking passengers to switch off electronics. They could fly an RNAV approach. If the weather's good, they could land visually. Worst case they can fly to a military base and make a ASR approach (I don't think this has ever happened with an airliner).

There's different levels of unsafe. You have to consider what the specific risks of each are.

Was there ever a missed approach due to a cell phone not being in air plane mode? How was the cell phone located? What would happen if the cell phone was in the luggage in the cargo bay?

Sorry, but this sounds all very hypothetical. This this was a real problem there should be other procedures by now.

> Was there ever a missed approach due to a cell phone not being in air plane mode? How was the cell phone located?

Here's a story of an interference event where they went missed:

https://www.quora.com/On-my-last-flight-before-landing-the-p...

A quick search through the NASA ASRS database shows several reports where the ILS or VOR receiver was behaving erratically, sometimes during descent. In some cases the crew was able to land visually, in others the crew crew had enough time to ask passengers to switch off phones and the problem went away.

See: ACN 695049, 321746, 307150, 277118, 200510, 161347, 364464, 467979

https://asrs.arc.nasa.gov/search/database.html

Most of these are older reports, take that as you will. It's entirely possible LTE doesn't interfere with the ILS/VOR. I honestly don't know.

Note also that this only lists reports made through NASAs reporting system. There are other reporting systems used by commercial operators (i.e. ASAP) that I can't easily query.

If I expand the search to include 5G interference, I get 97 recent results. That's a different issue, but at least worth mentioning to show that interference is still a general concern. I'm not going to list all of those, but you're welcome to query for them at the above link.

> What would happen if the cell phone was in the luggage in the cargo bay?

Then they would use one of the other contingency options I already mentioned to land visually or using other sensors. Still not a "safe" situation if this happens when you're close to the ground. If this were to happen during a Cat III approach, it would be extremely bad.

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