Just to dispel some rumors and try to help people's understanding of certain things. This will be kind of ongoing, but I need to get some work done now so apologies for the layout.
A lot of people are asking (quite rightly) if we can track the passengers
from their GPS enabled mobile phones:
Unfortunately, no. GPS relies on a constellation
of satellites orbiting the planet. Your GPS receiver, be it in your phone or a
"sat-nav" is just that, a receiver. The reason you can see where you
are on Google maps, for instance is that your phone’s GPS receiver interprets
the timing data from GPS signals and then transmits this information over the
data network to the internet. This is then interpreted and displayed in a
friendly format showing "you are here" in relation to the world.
Some GPS devices can transmit, but these are also
dependent on the ability to transmit over the airwaves, such as these SOS
watches you can buy.
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What about tracking data on the plane? ACAR’s and Rolls Royce engines both
periodically send out data, don’t they?
Yes. ACARs was present on the 777 that has gone
missing, but authorities have yet to solidly confirm if, and what information
was received. It’s also entirely possible that the flight wasn't airborne long
enough to transmit the next segment of information. The same can be said about the
information that the Rolls Royce engines transmit. If they only transmit a
burst of data every 30 minutes, and a disaster happened just after that up-link,
there would be no more data to send.
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Why, were some people able to telephone their relatives to have the calls
connected and then cut off?
Due to the nature of call routing, it can be
possible to hear the tone of the other party’s phone ringing before it
physically rings. You can try it right now, take a mobile phone, put it to your
ear and dial a phone in front of you. A good amount of the time, you will hear
ringing before the other phone receives the call, even by just half a second.
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How does a plane so large manage to just vanish from RADAR coverage?
If you imagine RADAR, which is a system of
radio-wave as a form of light you cannot see. A RADAR transmitter shines that
light and looks for something that glitters. Due to the curvature of the earth,
there’s a limited horizon at which RADAR becomes ineffective. In addition to
this, in the world of civil aviation the system uses transponders on the
aircraft. These boxes have information fed into them, such as flight number,
sometimes type of aircraft, heading, airspeed etc. These do not constantly send
out a signal. At a ground monitoring station, a signal is sent to say “Hey! Who’s
that?” and a response would appear on their ‘scope’ detailing information about
the flight, gathered from a number of sensors on the plane, such as GPS
receivers, compass, altimeters and instruments that measure speed. This is what
ATC will see on their screens. This can be augmented by “skin paints” where a
RADAR site actually shines on the air frame and generates a RADAR return. A bit
like shining a powerful torch on a foil balloon in the sky, you’ll see it and be able to work out where you are in relation to it.
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What about a mid-air collision?
It’s possible, but not probable. We haven’t heard
any other reports of missing, or damages planes in the area at that altitude, plus, don't you think somebody would have come forward by now if they damaged their plane in a mid-air collision?
There are a couple of types of missiles, a ground based unit would probably use RADAR guided missiles. One of these would potentially have the ability to destroy the aircraft in one fell swoop, this still wouldn't explain why the jet ascended to above the service ceiling to some 45,000 feet. It certainly wasn't to avoid the missile as some people are discussing online, because passenger jets, for the most part don't have threat receivers built in. To keep it simple, tracking RADAR shines a torch around and looks for shiny things. To guide a missile the band is flipped to a mode that a missile can follow easier. Generally fighter pilots will be able with their threat gear built in that they're being targeted and then tracked, so they can detect a missile may be fired a them.
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Hijacking? Isn't there some procedure for that?
As this is a big one that keeps coming up, details, details and more details.
The transponder of an aircraft, such as the 777 involved can be set to "squawk" a different ident' depending on the nature of what the aircraft is doing. A flight controller may ask an aircraft to squawk a certain ident' so that they can keep track of who's in their airspace. However, in the event of an emergency a pilot would set their transponder to 7700. On the ATC scope, a number of systems will automatically highlight this to the controller on duty. 7500 indicates a hijack, and 7600 would indicate lost comms.
However, all of this is secondary and redundant if the pilots wanted to turn them off, which there are a number of news stories demonstrating how this is possible floating around.
With staff potentially taking their own craft, it's theoretically possible to squawk the ident' of another aircraft entirely and follow the flight plan of another flight. RADAR can't tell you what type of aircraft it is. All you see is a reflection. RADAR operators tend to deduce what's in the airspace by the transponder, or in military terms, checking the speed of the flight, how the plane turns and what electronic emissions are being given off.
However, that's pure speculation at the moment. The police checking the home of the pilot and passengers is something that needs doing to chase down all leads.
The potential range of the aircraft with fuel on board is simply put; massive.
Image credit: TWITTER USER @KRISTOFERA
The image above won't be 100% accurate as a lot depends on how the plane was flown. Flying at optimum altitude would give them the max' range so we could be looking further than that, also a lot smaller as flying lower burns more fuel.
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Why do pilots have the ability to disable fundamental systems, such as ACARS and the on-board transponders?
This one's doing the rounds a lot at the moment. What needs to be considered is that when you think about ACARS and transponders, these pieces of hardware consume a lot of electricity and are BIG pieces of kit. Some ACARS units that gather data from around sensors scattered around the plane are the equivalent to a large PC tower. This will be plugged into some form of router, again more electronic hardware. Each of these pieces can cause a fault, and result in a catastrophe such as a fire. The same goes for GPS receivers, fuel pumps (yes, you can turn off a fuel pump during flight) because if one of these systems endangers the aircraft, you need to be able to isolate the hardware to prevent it doing further damage.
This is why pilots can disable hardware in flight.
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How come the CIA/NSA can't find the plane? I've read a lot recently about how our phones are tracked. Surely the CIA/NSA are covering up their abilities by not being forthcoming with the information?
This one pops up a *lot* - we've read a lot recently of how the all seeing five-eyes watch us, all of the time. There's simply no reason for the authorities to withhold this information. Were it still a secret how much we're (potentially) watched, there would be cause for not showing what you're capable of. There's no logic in doing so when people know of the scope of worldwide surveillance. There's a tiny chance that military SIGINT satellites could have captured some of this data, but thinking about it - there's no point in tasking a multi-billion-pound asset to intercept ACARS messages that can simply be pirated from the satellite that's there to deliberately listen to these. There's zero intelligence value in it.
Shootdown theory? Go on...
Alas, I think this is simply too implausible. There's a shedload of RADAR operating in that part of the world and missiles can be seen on RADAR.
There are a couple of types of missiles, a ground based unit would probably use RADAR guided missiles. One of these would potentially have the ability to destroy the aircraft in one fell swoop, this still wouldn't explain why the jet ascended to above the service ceiling to some 45,000 feet. It certainly wasn't to avoid the missile as some people are discussing online, because passenger jets, for the most part don't have threat receivers built in. To keep it simple, tracking RADAR shines a torch around and looks for shiny things. To guide a missile the band is flipped to a mode that a missile can follow easier. Generally fighter pilots will be able with their threat gear built in that they're being targeted and then tracked, so they can detect a missile may be fired a them.
Secondly, we have infra-red missiles. These would home in on the engine of the aircraft. When it gets to within a certain distance, a proximity fuse detonates the warhead and a cone of shrapnel is ejected toward the target. These things don't operate as you see them in films, where they embed themselves in the target and blow up. The cloud of shrapnel itself isn't guided and is in no way guaranteed to hit the target. Simple laws of physics keep it flying. This is called probability of kill, circle error probable.
More information on that, here: http://www.fas.org/man/dod-101/navy/docs/es310/dam_crit/dam_crit.htm
With losing one engine, it's doubtful the jet could ascend to 45,000 feet, then descend AND make the turn. Exciting as it may be to invent conspiracies about a shootdown, it just doesn't fit the flight profile.
...back to work.
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Did Courtney Love really find something?
No... For a celebrity to get involved in crowd sourcing is a pretty cool thing, but this is just attention seeking.
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Aliens?
Just.... no. Ok?
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