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Comment by viraptor | Hacker News Reader

I don't think it's about the danger to the passengers as much as forcing your way to the pilot. I.e. someone capturing/torturing passengers until the pilot comes out.

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I guess I simply don't buy that any terrorist on board -- even if there were several of them and they were armed with box-cutters and the like -- could ever take the cockpit. The doors are locked, the pilots are sometimes armed; and mostly, the passengers would never let it happen.

Even in the most extreme scenarios imaginable, the passengers would have a 20-1 advantage, and would understand that the cost of failing to neutralize the threat would likely result in their personal demise (not to mention the greater threat of using the plane as a weapon).

I've been on planes with about 20 passengers, so 2 or 3 terrorists could significantly narrow the odds.

That said, I don't disagree with your point at all.

I'd rather see an armed plainclothes officer on every flight than be harassed at the airport.

That size of a plane is too small to worry about. Commercial aviation is usually at least 50 seats. The TSA isn't preventing terrorists from chartering a private jet and flying it into something either.

I've been on 737s with about 20 passengers. It's rare, but given the right combination of flight, time of day, and season, it can happen.

This is of course not really testable, but putting other passengers in a position where their actions would directly result in someone else's death could change that. Would you really expect people to resist if someone started by binding random person and promising to stab them if anyone gets up? (yeah, starts like a bad action movie plot, but it could be relatively effective)

Locked doors and guns are one thing, and a pretty solid argument imo but... 20 american joe publics vs. any small number of arabs, maybe even just one?

Fear of death is not such a great motivator as you imagine I think.

have you seen people react to threats in the wild? especially from the first-world white middle class background? its just not a part of their life and generally they do really stupid things like freeze or panic wildly, shoot first and ask questions later...

a lot of these terrorist guys come from very tough environments with aggressive cultures that make the south of USA look tame... if they panic or freeze up when death is imminent they are likely die and leave no offspring - and these situations occur much more frequently so that there is a very strong selection pressure to compete in that regard which is absent from most of western society, modulo wars, for at least three or four generations now...

> any small number of arabs, maybe even just one?

Any small number of people.

There is no need to single out certain cultures.

Thank you. Equally could have called them American allies (Saudi). I can distinctly remember the feeling in late 2001 that people would look back at the reaction to events in a similar way to how we look at the McCarthy era or other such witch hunt and demonization type events. I don't think we have reached that place yet, but it's closer than it was.

Of course, it's equally insulting to say that people from a white middle-class background can't react effectively to emergencies.

it was an example... and a good one.

i strongly disagree with the sentiment that we can't use races, sexes etc. to discriminate (we shouldn't use it to privilege or under-privilege people for sure, and thats the real issue with racism, sexism etc.) - there is real measurable data there.

p.s. i am an arab. i can understand why arabs in particular would be inclined towards becoming anti-US terrorists too... its not very complicated or deep, and certainly not racist.

20 american joe publics vs. any small number of arabs, maybe even just one?

I didn't know having an arabian background turned you into some kind of superhuman ninja. Or are you just slightly confused and a bit bigoted?

It's a good thing evolution doesn't work that quickly. Selection has less of an effect than you portray in this case. If it were true, it would be all middle-eastern countries winning the olympic events.

and black american people make excellent athletes - and that has nothing to do with selective breeding in the slave trade?

evolution is maybe not the answer, but my experience tells me that survival skills lack in my surrounds.

It's also worth noting that anyone attempting to use a plane as a missile against a particular target is fighting the clock. It would take some time for the hijackers to breach the cockpit (whatever the method), and in that time it is highly probable that military jets have been scrambled and are inbound.

I'm also a bit curious just how difficult it would be to take down a modern jetliner if you had the run of the back of the plane and whatever you could legally bring on board.

Using the plane as a weapon and bringing it down are very different objectives. The chief concern here is using that plane as a force magnifying weapon. If you wanted to pop a hatch in the floor and start messing with the avionics bay, you'd rather easily scuttle the plane.

The pilots knows the same as the passengers: That if the hijackers take the cockpit, odds are nobody lives, so in a crisis, his best strategy for both personal survival and for saving the most passengers is to get the plane on the ground as soon as possible.

If a hijacker "just" wants to perform an old-school hijack, ie. not use the plane as a 9/11-style missile, his best odds are convincing the captain of that fact without taking the cockpit. The hijacker can verify that the captain is complying using a smartphone with GPS.

Fun fact: Smartphone GPS doesn't work above 10K feet, such that it can't be used to terrorize airplanes.

Don't you see, you're only helping the TERRORISTS by pointing that out. :)

Anyway, in that case, they'd have to remember to buy one of these first, then: http://www.amazon.com/Bad-Elf-1000-30-Pin-Receiver/dp/B0035Y...

Is that an actual limitation of the GPS network, or a limitation of the client-side software.

My understanding is that GPS satellites broadcast a timestamp, and the receivers use that information to compute their position. Assuming that this is accurate, devices should still be able to get the signal at higher altitudes. The only way I can think of this not working is if the geometry works out so that at 10K feet you are no longer in ranges of 4 satellites. I suppose this could be done my calibrating how wide to make the signal (which would make the signals stronger on the ground, but require more satellites for full coverage). This would likely also require having been thought of back when the GPS network was planned.

Also, I would imagine that planes use GPS, in which case it would have to be a client-side restriction.

Client side (may be in firmware or software): GPS above certain elevations or speeds requires a special export license that your smartphone probably doesn't have. An unlicensed device is required to output no fix (but it has to be able to calculate that the parameters are outside the allowed range).

http://ravtrack.com/GPStracking/cocom-gps-tracking-limits/46...

How difficult would it be for someone to work around these restrictions? If I have an unlocked Android phone, would I be able comment out the range check and recompile the gps software?

It's probably either in the driver for the gps chip or the gps firmware; neither of which are likely to have source available for you.

10k feet sounds a bit low. i thought the limit was at 60k feet and 600MPH

I don't think passengers would ever allow this to happen.

I thought the cockpit doors were actually sealed until the plane landed, i.e. the pilots couldn't open them even if they wanted to?

Pilots can definitely exit to cockpit (they do this routinely to use the restroom, and flight attendants sometimes barricade the forward galley with one of the service carts)

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