Why couldn't a crashing airliner just

I’ve been wondering about this for awhile and I thought I’d give it the SDMB sanity test. Wait, maybe that’s an oxymoron. Anyhow…

Most airliners now have those in flight phones that you can use to place a call to your ISP from your laptop. When an airliner crashes, they go to great effort to recover the “black box” and voice recorders so the FAA can figure out what happened. So the idea is this. If a plane has trouble, the pilot flips a switch or maybe automatically a dangerous condition is detected. Anyhow, why can’t a computer connected to the flight data recorder use the airphone link to place a call to a special phone number and start dumping data to a computer on the ground using a plain old modem. You could send a lot of parameters including GPS data and it seems to me that most of the equipment necessary to set up this flight data link is already in place on most planes That way, they’d know where the plane went down and have a pretty good idea of how and why. Anybody see any reason why this couldn’t work ?

>> Most airliners now have those in flight phones that you can use to place a call to your ISP from your laptop

they do? I have not seen them yet. And I have not even seen the power outlets on your seat that let you plug in your computer and not have to use the batteries. I have been hearing about them but not seen them. Much less inflight internet. Maybe you fly first class?

A very good question - why don’t they have something like that already? No need to use the phone service - they could reserve a radio frequency band.

On a related note, there was a UL going around by e-mail that claimed there was a recording of an Alaska Airlines passenger’s last phone call to her husband, transmitted via airphone. Terribly tragic to listen to, but a hoax nonetheless.

I am not saying it is not possible but it is not so easy as it sounds. What is the amount of information stored in a black box? I believe it is at least 30 mins of technical data in one and 30 mins of cabin voice recordings in the other. You would have to guarantee that all this data was sent and received and in a question of seconds. I do not believe it can be done reliably. A better alternative might be duplicate black boxes a set of which would become free and float and be equipped with EPIRB. That would save us if the other set cannot be recovered. But I cannot see radio transmission as viable.

I don’t think that the phone link could replace the black box but it would be an easy way to send real time info. I agree, you couldn’t dump the whole black box data quickly but I think you could send a lot of parameters in real time, especially if you had decent compression. It would remove the need to find the black boxes quickly at big expense.

It may just be that in some of the most important cases, like fuel tank explosions or terrorist bombs, there won’t be time to do this.

Staying with the balck boxes is cheaper than retrofitting all those old planes with the equipment you suggest, and they do an adequate job when maintained. Why replace them?

real time info? no way! You are going to be transmitting all the stuff over the air for every plane just in case one goes down?i cannot think of anything more wasteful of bandwidth. Not to mention you’d have to have dedicated receiving stations in all sorts of remote places… and what happens if the transmitter goes out? The black boxes are designed to work under the worst conditions. The more I think about this the more it seems clear that they’re doing it that way because it’s the best solution.

The ability to do USEFUL real-time data logging in commercial aircraft exists. In Europe, some airlines have what are called Quick Access Recorders (QAR) on board that record dozens of flight data parameters to tape. At the end of each trip, the tape is swapped out, and the data gets plugged into a database.

What this provides is an ongoing picture of an airplane’s performance as well as the pilots’ performance, rather than the US autopsy recorders. If an American plane goes down, we have to hope the the flight data recorder (FDR) was recording data that will tell us what happened. Many of the older FDRs only record a dozen or so parameters. Something as seemingly simple as speed could take a dozen parameters - pilot’s control input, autopilot input and actual engine speed, multiplied by four engines. Add a channel for indicated air speed, and you’re at thirteen channels. Just for your speed. Instead, we’re limited to measuring either the throttle control position or engine speed on just one engine, so we can get some other data.

The European QAR will show a minor disparity between the pilot’s pressing on the rudder pedals and the actual position of the rudder. Next week, the QAR tapes show the disparity increasing. Plane is flagged for maintenance. The sticking control valve is replaced without incidence. Here in the US, we won’t know the valve was sticking until it fails and the plane goes down.

Yes, we could easily have real-time transmission of flight data to the ground. The technology is certainly available. Availability of “airspace” would be an issue.

As for why American airlines have such low-capacity FDRs in their planes, and why we do absolutely nothing with all that recorded data until disaster strikes, it all comes down to money. The airlines are betting that the cost of wrongful death settlements will be less than retrofitting their fleets. They may be cold-hearted and callous in this regard, but if you remove the “people might die” aspect from the reasoning, it is the better long-term business decision. From a humanitarian point though, it sucks.

I think I have a copy of that one:

He: What’s happening now?

She: Everybody’s yelling. It’s hard to hear. The flight attendant is screaming about video games and lap tops and something else.

He: Huh? In the middle of an emergency?

She: Yeah, typical bureaucratic crap. You’d think–what was that?

He: I love you, honey.

She: I love…

One good reason might be that an emergency sufficient to cause a crash might also be sufficient to disrupt radio communications. I would imagine that if the pilot knows that there’s a problem of some sort, he’s talking to the folks on the ground about it anyway, if possible. The recorders just supply more information, to add to that.

Also, the most common time for an accident is on landing and takeoff, where there may be no warning at all, and if there is it’s only a matter of a couple of seconds. And during this time, you certainly can’t have the pilot be distracted by switching on a transmitter, so the black box would somehow have to ‘know’ that there is a problem, which may not be feasible.