I'm a software engineer.

The data stream recorded by the black-box flight recorder would be pretty small in size compared to the data requirements of in-flight wifi, which Boeing itself offered for a while before giving the business up in 2006.

Archiving the data is, frankly, trivial in the context of the IT operations of a major airline.

Whether live streaming of flight recorder data would actually make a substantial improvement to air safety is debatable. But, technically, it's very much in the realms of feasibility.

Planes fly miles in the air. The recipients of their data would have to be on the ground or in satellites. When Internet access is sold using satellites, the uplink is usually done with a phone link, not over the air. Wireless operates under square of the distance laws. Look at the communications network NASA needs.

BTW, this is not a software engineering problem.

Just a quick one about the Air France.

You mentioned (if I read correctly) that a plane can go too fast and suffer either structural damage or a loss of lift due to the wind being too fast over the wings?

I can understand it could reach such speeds in a dive, for example, but I got the impression you were suggesting this could happen on level flight, i.e. the pilots did not realize how fast they were going.

I am presuming I've misunderstood this, as I cannot fathom a plane designer allowing the thing to go faster than it is physically capable of.

but I'm pretty sure current GPS technology won't work underwater. Considering that just standing under a porch can throw off the coordinates, I'm sure that thousands of feet of water would be crippling.

On target again, as usual. I'll take his factual, reasoned, experienced explanations over anything else until he's proven wrong. And another observation: he never states his opinions as facts. That's a good rational, scientific attitude, in short supply today.

The local media in Washington DC had many problems with decent reporting on the recent fatal crash on our METRO system. For a while they couldn't even figure out which directions the trains were going, and they didn't bother to ask.

Patrick,

I think you might need to rethink this sentence: "As could other things, many of them very simple, such as designing a black box able to emit a long-range GPS signal so they can find the damn thing, instead of relying solely on a sonar pinger."

I'm not entirely sure what you mean, but "long-range GPS signal" is kind of hard to wrap my head around. This seems wrong on so many levels I'm not sure how to respond:

- GPS works by receiving satellite signals and comparing signal characteristics from several satellites, not emitting a darn thing

- GPS satellite signals are rather extra-ordinarily resistant to travel through water. Just a few feet of water will render a GPS signal useless. As soon as the black box was 5 feet below the surface of the water, it would lose its GPS signal, and hence have no way to confirm its location.

- just about any sort of radio signal in water other than extremely low radio frequencies, does simply not make it through very much water (maybe at most a few hundred feet). - Any "long-range" signal in water simply has to be sonar, at least until they perfect the mythical "ULC" underwater laser - which in any case is more of a directional communication method.

I can't fathom (pun intended) any sort of solution for underwater communication other than one that is sound-based. The science simply isn't there.

Mark

You mentioned (if I read correctly) that a plane can go too fast and suffer either structural damage or a loss of lift due to the wind being too fast over the wings?

I can understand it could reach such speeds in a dive, for example, but I got the impression you were suggesting this could happen on level flight, i.e. the pilots did not realize how fast they were going.

Planes need to be able to climb as well as cruise and decend. Climbing needs a higher ratio of power over level flight than climbing a hill does in a car. This power is always available to the pilot, which is why manufacturers publish "never exceed" speeds.

It would take multiple instrument and sensor failures for the pilot to not be aware this was happening.

But it might not. So why not 1)make it buoyant to the extent possible and 2)locate it within the aircraft (with all relevant engineering and design contingencies considered) so that it isn't likely to get wrapped up in heavier, non buoyant materials and sink?

I don't think that question was properly addressed.

Oh, and were the black boxes from any of the planes that were hijacked on 9/11 ever recovered? I am seriously just wondering - I have no idea nor the gumption to go look for the information.

There's a terrific old engineering saw that goes as follows:

Stronger, lighter, cheaper; pick two.

In other words, you can have strong and cheap, light and cheap, but strong and light is going to be expensive.

In terms of flight black boxes, this might be rephrased:

Able to survive crash forces, able to detach/float/play the banjo, cheaper than the plane itself; pick two.

And the airline industry has clearly chosen to make a device that maximizes its crash survivability, while being cheap enough to install on all commercial aircraft.

It's that simple.

I recently flew from Buenos Aires to Auckland and as the Great Circle Mapper shows, the plane heads a long way south with probably over nine hours crossing the open Southern Ocean. At one point, I did wonder - where is the nearest airport? Tahiti is a long way north of 60 degrees south.

Is the three hour rule always adhered to? Are there circles which airlines are not permitted to fly?

It answers my earlier question - at one point a plane between Argentina and New Zealand is more than 4 hours away from any airport but within five and a half hours.

I flew in an Aerolineas A340 with four engines so a 330 could not fly this route. I would presume a blown engine five hours out from an airport on a four engine plane is not a significant problem?