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Missing Airplane Flew On for Hours

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Re: Missing Airplane Flew On for Hours

#101

Post by hueving »

ars wrote: post #89
rdl wrote: post #76

Earlier quoted context omitted.

Why ground? I'd do that as an L-band ORBCOMM type system, since it's going on planes operating over oceans. $0.01/character.

So why don't planes do that that? You need 24 bits for 3 meter GPS accuracy (times 2). Add some extra for altitude and airplane ID (or does a unique ID come built in?) So maybe 80 bits in total. This would be nothing for an airplane - $0.40 per hour? Why don't they do this already?

>This would be nothing for an airplane - $0.40 per hour? Why don't they do this already?

They would likely receive pushback from private jets that don't want all of their flight path transmitted back to RR.

Re: Missing Airplane Flew On for Hours

#102

Post by downandout »

This begs the question: why on earth is it even possible to turn off a transponder mid-flight on a commercial plane carrying hundreds of human beings? I also don't understand why, if we can send bursts of engine data every 30 minutes from the middle of the ocean, we can't send a GPS location every couple of minutes. Maybe even throw some GPS data in with the engine data - at least we would know where it was within a 30 minute window. We're talking about a few extra bytes.

Re: Missing Airplane Flew On for Hours

#103

Post by hueving »

agildehaus wrote: post #22
United857 wrote: post #15

Earlier quoted context omitted.

It's possible in some cases for phones to "ring" even if they're off/disconnected, as the tone is generated by the network, not the device itself.

In my experience the network won't ring if it hasn't seen the device in a certain time period. "Straight to voicemail" for that. I'm no expert though, maybe rings are still possible. But if the network is seeing these phones, it seems to me it'd be pretty simple locate these people by just querying the provider for the tower location. This hasn't happened, so the only conclusion is all the phones were destroyed, disa…

>In my experience the network won't ring if it hasn't seen the device in a certain time period. "Straight to voicemail" for that. I'm no expert though, maybe rings are still possible.

You are correct, rings are still possible regardless of the state of the phone connection.

Re: Missing Airplane Flew On for Hours

#104

Post by munkeegutz »

elemeno wrote: post #73
chrismcb wrote: post #48

Here is what I don't get. A plane, a HUGE plane, supposedly just disappeared. Near China. So this whole "fly under the radar" is just BS? You just need to turn off your transponder, and you can fly wherever you want?

The range at which Radars can detect planes is a lot shorter than most people seem to believe. Ground based Radars have an effective range of something in the region of 200miles due to the earth's curvature. To get around that you either have to have air based Radars (such as the E2-Hawkeye used by US carrier groups), or more exotic/experimental types of radars which bounce off the ionosphere. The limitations of rada…

In addition, the critical frequency for the ionosphere is ~10MHz (that is, above that frequency, you can't really bounce a meaningful amount of energy off the ionosphere, most passes through). 10MHz = a wavelength of 30m. So in general, you'll only be able to detect things about 100ft or larger in size (and that's a lower limit-- practical is probably bigger). I'm not at all surprised that you'd need line of sight to track a plane. Knowing that there's something there is easier, but tracking is trickier.

Re: Missing Airplane Flew On for Hours

#105

Post by emeidi »

haldujai wrote: post #17
digitalengineer wrote: post #9

So we have a plane that flew to another destination without communication and several people with bogus passports on board. Familymembers have reported cellphones that kept 'rining' instead of going directly to voicemail (as they would have if the plane was at rhe bottom of the ocean). Hijacking looks to me the only reasonable explenation.

This statement has to die. It has been confirmed over and over again that the phones aren't on and this is a network thing. Do you really think that if this plane was hijacked the phones would be kept on especially in light of the Snowden/NSA leaks? Tracking cell phones has been common for over a decade now, I'm sure a hijacker would be aware of this and would toss the cell phones into the ocean.

Like in opening the door at flight level 295 and throwing out a bag full of mobile phones?

Re: Missing Airplane Flew On for Hours

#106

Post by KhalPanda »

yeukhon wrote: post #86
tn13 wrote: post #68

Why no one is paying attention to the fact that the plane was flying over South China see which China is trying to claim for itself. Could it be the case that China by mistake shot the plane down ?

Impossible. The consequence of hiding the truth is an international shame. And do you really think any country launching a missile can go unnoticed? You know that area is under dispute and nearby countries are claiming ownership, meaning they are actively monitoring all military actions. There are satellites watching that area too. No. No. And why China? I think this is more of an anti-China/China conspiracy. You got…

I don't disagree with you, but this part got me:

"And do you really think any country launching a missile can go unnoticed?"

A few days ago... no, I didn't think so. But apparently a massive xxx ton airliner can go for hours unnoticed, so...

Re: Missing Airplane Flew On for Hours

#107

Post by TomAnthony »

omegant wrote: post #95
retrogradeorbit wrote: post #84

Earlier quoted context omitted.

The best part of this theory (which I think is good) is: "Losing Helios 552 might be a freak accident, but if decompression and a locked door led to the loss of MA370 as well, then this would be a new threat that will now have killed 360 air travellers—many times more than have died as a result of hijackings since 9/11. Is it appropriate to employ anti-hijacking measures to prevent violent hijackings a couple of time…

There is a code that can be used by the cabin crew to access the cockpit in this cases. It's cancelable from the inside, so if a hijacker tries to use it you can put it of once it starts ringing(it rings for 30 seconds and then opens the door). So this case of pilots unconscious is covered. Any way I agree that the spending after the 9/11 is insane and unecessary.

That seems like a good solution. Why did the crew of the Helios flight not do that?

Re: Missing Airplane Flew On for Hours

#108

Post by mseebach »

nostrademons wrote: post #39
ekianjo wrote: post #24

Earlier quoted context omitted.

> * On February 22nd, aircraft 9M-MRO underwent maintenance. During this, or during a previous maintenance cycle, an empty oxygen bottle was installed by mistake for a full one, or a valve was jammed, or some other undetected fault rendered the flight deck crew's emergency oxygen supply inoperable. That sounds extremely unlikely. Standard procedures for equipment checks in plane are usually done at 9 sigma standards,…

The other thing to consider is that there are roughly 90,000 flights/day and 365 days in a year, so even if such an event has a probability of 1 in a billion (that's roughly 9 9s reliability), you'd expect it to happen once every 30 years on average. Extremely unlikely events become plausible when large numbers are involved.

I don't think the 9-sigma is calculated per operation cycle, I think it's per maintenance cycle which are from a few times a year to every 5 years, depending on the type.

http://en.wikipedia.org/wiki/Aircraft_maintenance_checks

Re: Missing Airplane Flew On for Hours

#109

Post by mseebach »

noobermin wrote: post #58
mootothemax wrote: post #51

Earlier quoted context omitted.

If the cargo was the interesting bit, killing off all the passengers by dropping pressure and oxygen is trivial. When was the last time a criminal killed ~240 people in order to steal some loot? The solution proposed would, at best, be extraordinary; flippantly adding mass murder makes it absurd.

I mean, it would seem easier to steal the cargo at the airport before it got on the plane, just bribe a few ground workers, I guess. Steal some passports, hijack, then divert the plane just for cargo? It wasn't the cargo; the only reason to hijack the plane would be either the people or the plane or both. Or, it was an accident.

http://en.wikipedia.org/wiki/Brussels_Airport_diamond_heist

Re: Missing Airplane Flew On for Hours

#110

Post by userbinator »

ars wrote: post #89
rdl wrote: post #76

Earlier quoted context omitted.

Why ground? I'd do that as an L-band ORBCOMM type system, since it's going on planes operating over oceans. $0.01/character.

So why don't planes do that that? You need 24 bits for 3 meter GPS accuracy (times 2). Add some extra for altitude and airplane ID (or does a unique ID come built in?) So maybe 80 bits in total. This would be nothing for an airplane - $0.40 per hour? Why don't they do this already?

And since this plane is far larger than 3 meters, it doesn't even need to be that accurate; 50 meter GPS accuracy would be good enough.
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