I've just read this article about the disappearance of QZ8501 and was surprised by the following statement:

Even with automated beacons (we can assume these weren’t used, weren’t on board or were intentionally disabled) and EPIRBs, losing an aircraft is actually not that difficult.

Now, is it?

I was under the impression that if Breitling can make a watch with a 406 MHz distress beacon, a €70 million aircraft must surely be equipped with an automated ELT that can start to transmit automatically and whose signal can be picked up by [LE/GE]OSAR.

As it seems, US-registered civil aircraft are not required to carry 406 MHz ELTs while aircraft registered in Australia must be equipped with ELTs that operate on both 406 and 121.5 MHz (see the same reference).

Can you shed some light upon what is the current state of ELT regulations, how ELTs fitted to commercial aircraft operate in case of distress (automatic/manual?), what are the relevant regulations for EU-registered aircraft, and how can one lose an aircraft when all these systems operate?

I don't buy that “losing an aircraft is actually not that difficult” if all available technology is used (even assuming little redundancy and an adequate price range).

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    A general remark (not sure what the article says) but an ELT dropped in a big body of water like the ocean, is pretty hard to find. The range of the signal in water is severely limited (compared to the size of an ocean), and you need to take into account that the distance from the ocean floor to the surface which might be substantial as well. – falstro Dec 29 '14 at 22:57
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    @falstro The article is focused on non-emergency radar contact, briefly mentions that GPS is a one-way connection, and ELTs are only mentioned in the quoted bit (apparently as EPIRBs). While you raise a good point relevant to the process of actual rescue, we are only interested in locating the crash site for which the last transmission above ground should suffice. 406 MHz ELTs transmit a burst of signal every 50 seconds, which, assuming GPS data are included, should greatly reduce the search area (even without GPS, it should be approximately 3 nm). – Harold Cavendish Dec 29 '14 at 23:06
  • It is now confirmed that QZ8501 wreckage has been located close to the position of the last contact. – Jan Hudec Jan 3 '15 at 21:37
  • Actually, when crossing the big pond from Europe to the Caribbean I sometimes think about how incredibly difficult it would be to find a plane back when we haven't seen a ship or plane but only water for 9 hours straight...... There is a lot of surface on the earth when you think about it.... – Ron Oct 23 '15 at 20:53
up vote 6 down vote accepted

It is certainly possible to build an aircraft using modern technology that is hard to lose. After all, aircraft have GPS receivers and passengers can watch YouTube in the cabin. All you have to do is integrate those two and send the exact GPS position to a ground station as frequently as you want.

However, the global aircraft fleet is not so capable. Some aircraft have satellite internet capability; some do not. For those that do, the internet connectivity is completely isolated from the aircraft navigation systems. (After all, you don't want any possibility that an aircraft in flight could be "hacked" by someone on the ground.)

Retrofitting an existing aircraft (which could be up to 40 years old or more) to add such capability would be a very expensive job. Retrofitting an entire fleet (with perhaps many different aircraft models) is astoundingly expensive. Existing aircraft navigation and communications systems are so good that losing an aircraft "almost never" happens (yes, it's happened at least twice this year), compared to the number of successful flights. The airlines probably consider upgrading their fleet to support this kind of continuous surveillance not worth the expense, when compared to the probability that one of their aircraft actually goes missing.

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    Also, making it work anywhere in the world is significantly harder than just making it work. – Lnafziger Dec 30 '14 at 2:18
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    I thought that the SARSAT system covers the whole world and according to the data I've found, 406 MHz ELTs for aircrafts cost around a thousand US dollars which is not much, really. Is there perhaps some drawback to the system that I'm not aware of? (cc @Lnafziger) – Harold Cavendish Dec 30 '14 at 8:24
  • The initial cost might be small but it's 100's of millions world wide. Now add the maintenance and service costs and the cost, environmental and fiscal, of all the extra fuel to carry them around. Add the limited usefulness (exactly what benefit do you think they would provide?) and it doesn't make so much sense. – Simon Dec 30 '14 at 22:54
  • @HaroldCavendish Most of them DO have ELTs, but they don't work very well under water, as you know. – Lnafziger Dec 31 '14 at 21:00
  • No, it only happened once the already last year; QZ8501 wreckage has already been located. – Jan Hudec Jan 3 '15 at 21:38

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