Do airliners carry something like this?

I had a thought after hearing another report on the failure to locate the missing Malaysian airliner. It seems so obvious to me I can’t see why it hasn’t been implemented before, but I can’t recall hearing of such a thing.

The idea is to distribute about the airframe a bunch of small buoyant mini-beacons. I imagine them being about the size of tennis balls, but maybe bigger would be better. They would be activated either by immersion in water or by experiencing extreme shock. Each would then transmit in a similar way to Breitling’s Emergency Watch. By having enough of these at strategic points of the aircraft would greatly increase the chance that at least one will be ejected from the wreckage. That way the crash site can be found even if the plane sinks without visible trace. I know there is often some sort of locator transmitter on the black-box and cockpit voice recorder, but there is no guarantee that these will not be damaged or submerged.

Any thoughts?

The data recorder and voice recorder (which are orange boxes :wink: ) do have locating devices. The aircraft also carries an emergency locator transmitter that is activated by the shock of a crash. (Or manually; but they’re less accessible in a ‘heavy’ than in a General Aviation aircraft.)

An ELT weighs about a kilogram with mounting hardware. A ‘bunch’ would weigh a lot, and weight is always an issue in aircraft. Of course you’d have to find places to mount them all, and the mounts would be heavier than normal mounts if they are supposed to release in a crash. Flotation materials will add weight too. All of them would need to be accessible so that their batteries can be changed on schedule, so you’d have to modify the airframe. No doubt there would be a certification process. Maintenance times would increase, and those batteries aren’t free. I’m pretty sure they’re not AA cells you can pick up at the Wal-Mart. A military radio/beacon I have takes a weird gel-block kind of battery. In the event of a crash – which is rare, and the ones that do happen don’t always happen over water – you’ll have a ‘bunch’ of beacons that would have to be found and deactivated. This would be difficult in water, with currents and such, and in rugged terrain.

So you’re adding a lot of weight, a lot of time, and especially a lot of expense to solve a problem that rarely occurs.

Interesting idea, but all of these mini-EPIRBs need batteries and periodic testing. The unit on this page is designed for fishing vessels and comes with a case that will automatically deploy and activate the device if the vessel sinks.

The question is how to mount these to aircraft? They need to be accessible for battery and function testing, so there’s brackets and holes that all need to be obsessively engineered, tested and certified. They should be on the outside of the aircraft for best chances of activation in case of a crash, but they need to be immune to the vibrations of normal flight, and they need to be immune to weather.

They’ll probably also need to be incorporated into the plane’s electrical systems. Not so much for battery charging, but so the devices can get regular GPS coordinates and to confirm that the device is still on the aircraft.

We’re in a market where airlines boast of saving bushels of dollars by doing seemingly trivial things like removing one olive from each salad. Do you really think anyone’s going to willingly foot the bill for these devices? My vote is “not until they’re required by law.”

Up till now, the current technique of marking the crash site with flaming wreckage has worked well enough.

That reminds me of a comic book I had when I was a child. A story involved an RAF raid over Germany, and the target was to be marked by a green flare from a pathfinder aircraft. I don’t recall if it was a Lanc or a Mossie, but there was some drama with one of the pilots. The plane took a hit and was going to crash. So the pilot aimed his aircraft at the target and told everyone to look for the red flare – which (he didn’t tell them) would be his aircraft crashing into the target.

A better solution to the missing Malaysian airliner would have been to design the plane so it wouldn’t crash in the first place. Which illustrates the problem with this sort of thing: You can’t really plan based on individual events.

that didnt work out so well with the titanic when they tried it

I kind of wonder if they had a slow leak? There was a case about 20 years ago where a small jet lost pressure over the eastern seaboard. IIRC it was carrying some university’s football coaching staff. It flew on autopilot on an erratic course until it flew out into the Atlantic, then cost guard watched helplessly while it lost power when fuel ran out and dropped into the ocean.

If the crew did not realize in time that they were slowly starving for oxygen, then they could start acting like they were drunk and disoriented; do weird things like turn off electronics, turn 90 degrees, etc.

Would alarms go off and the oxygen masks pop out? Don’t the air crew wear masks sometimes?

You get alarms in the cockpit and the passenger oxygen will drop automatically. This happens well before the oxygen levels get dangerously low and the immediate response from the crew should be to don their oxygen masks. It’s not unheard of for the crew to get caught out, but they have gone to sleep rather than doing weird things.

I’ll cross-post this (here and the one proposing cloud storage)

Since ACARS has solved the problem of converting status into an electronic beep (and, I’m guessing, a digital one at that): if DSL uses (or used) telephone wiring, the idea of piggybacking data on existing wires is probably solved.
Turn the planes wiring harness (I don’t want to see what it looks like on those monsters) into a transmission network an use a small digitizer of some sort recording to a USB/RFID/whatever chip inside a literal orange tennis ball (lightweight version) stuck between the hull and the interior plastic panels. attached to hull with the equivalent of Post-it [sup]TM[/sup] adhesive, so they don’t fall out every time maintenance opens the panels
Anytime a hull is breached, a dozen or so of these fall out.

No addition wiring - huge cost savings right there, about a half pound or so for ball and digitizer.
What’s wrong with this pic?

There was a similar case in 1999: Learjet carrying pro golfer Payne Stewart, three other passengers, and 2 crew, bound from Florida to Texas, did this. Plane on autopilot, didn’t follow intended course, flew for 4 hours on auto-pilot to South Dakota and crashed there.

Wiki article:

ETA: Several Air Force jets intercepted and followed it, but couldn’t do anything.

Nationwide news media (radio, TV, papers) covered the entire flight in real time pretty much non-stop for the entire four hours.

If he pressure leak snuck up on them, the pilots slowly succumb to hypoxia where they become very confused and almost like they are drunk - could do stupid things like switch off he transponder and change course before losing consciousness.

The problem is, you would think that there would be all sorts of alarms - for example, you would feel your ears popping a lot as pressure bleeds away. I don’t imagine the passengers sitting passively wearing their drop-down masks with no feedback from the unconscious cockpit for hours. Within a few minutes, someone would have dragged out their phone and texted someone - it would be another hour over the Malay peninsula then Aceh, I would guess.

The titanic never even got off the ground.

Au contraire, it was far, far above the ground for most of its maiden voyage!

Yeah, but that water landing was a doozie.

You’re probably thinking of the 1980 crash that killed Bo Rein, the new head football coach of LSU and former head coach of North Carolina State.

Yeah, that’s the one. I got the impression from the news that it was a small jet. (41,000 feet! In a turboprop!) I assume without a radar or a transponder, it would have been acomplete mystery where it ended up.