Breaking: Possible wreckage of MH370 found

[SpottedKitty]

Apparently some other airplane crashes near reunion included a 747 and other Boeings, so one has to wait for identification number confirmation. Should be a few days or so.

FWIW, the TV report I saw earlier mentioned that the barnacle growth sprouting in a few places suggested it had been in the water "about a year". One more data point to help pin it down?

[Tribble]

Or, they could just have all commercial jets send out GPS coordinates and other data throughout the entire flight. I'm surprised that's not standard by now.

[Broomstick]

Well, there are still some 50 year old commercial jets flying in the world and I'm not sure how feasible it is to upgrade all of them, at least not in a 100% reliable manner for the purposes stated.

Going forward sure, have it on the new jets, but given that a commercial jet can easily last decades upgrading the entire fleet can take awhile. And cost a crapload of money.

[Borgholio]

Having older jets shouldn't prevent installing a simple satellite dish in the tail section somewhere that can transmit position, altitude and speed. If we had crash data even down to a few square miles, that would narrow down the search considerably.

[Broomstick]

Sure, no problem.... we'll just find somewhere on the tail - you know, where a lot of the steering mechanism is located - that doesn't interfere with vital operations and where the airflow past the fuselage and bouncing off the flight controls as they move doesn't either knock the dish out of alignment or rip it entirely off the airplane.

It's not impossible to retrofit older airplanes (with something that we actually know will work) but the cost would be considerable. You can't just bolt shit onto an airplane, there's all sorts of regulations, paperwork, and procedures. Not to mention that the weight and location has to be taken into consideration and possibly other weights installed elsewhere to compensate for it where it won't interfere with anything important and, well, I'm not a mechanic for a large body jet so I'm probably missing a few things here but installing equipment in any airplane is more complicated than it initially appears to a layperson.

[Borgholio]

Sure, no problem.... we'll just find somewhere on the tail - you know, where a lot of the steering mechanism is located - that doesn't interfere with vital operations and where the airflow past the fuselage and bouncing off the flight controls as they move doesn't either knock the dish out of alignment or rip it entirely off the airplane.

I did say "IN" the tail...not "ON" the tail. Bolting a dish on the outside of a plane is rather foolish, ya know? I was referring to a small GPS transmitter installed inside the body of the plane. They have portable transmitters the size of a cell phone you can carry in your pocket...so aside from possible radio interference issues (which naturally need to be thoroughly tested), how difficult can it be to attach a cell phone-sized object to the inner wall of the fuselage? If they need a larger antenna, say the size of a dinner plate...is it really that cramped for space back there?

I'll concede that the regulatory and certification processes for such things will be much harder than the physical / technical aspects...but it is doable if they wanted to.

[Broomstick]

If they need a larger antenna, say the size of a dinner plate...is it really that cramped for space back there?

Hard to say - there is a LOT of stuff going on in the tail, and some very tight choke points.

I keep forgetting how much smaller GPS units are than they used to be.

Maybe they could somehow incorporate it into the housing of the black boxes.

[Thanas]

Does one really want to put more weight than necessary into the tail anyway, considering how much strain it is under?

[Elheru Aran]

Wouldn't it only be a few ounces, possibly only up to a pound depending on how tough it is? Electronics these days can be *really* miniaturized...

[EnterpriseSovereign]

Hopefully this piece will reveal more than simply which plane it came from, if that's even possible.

[Thanas]

Wouldn't it only be a few ounces, possibly only up to a pound depending on how tough it is? Electronics these days can be *really* miniaturized...

Maybe though it would need to reach satellites considering how much of the earth is without radio coverage.

[EnterpriseSovereign]

Wouldn't it only be a few ounces, possibly only up to a pound depending on how tough it is? Electronics these days can be *really* miniaturized...

Maybe though it would need to reach satellites considering how much of the earth is without radio coverage.

Presumably it would be tied into the plane's existing transmitters- of course if the plane doesn't have those to begin with then it's a bigger problem.

[Thanas]

One can switch those off, the idea was to create an independent system.

[Luke Starkiller]

There are also significant ongoing expenses for a system like that; one of my customers operates B737's and had live satellite TV systems installed, including independent antennae. They no longer use that system but still have to have inspections carried out regularly; hangar the aircraft for maintenance and have a certified Eddy Current inspector brought in to inspect for cracks.

[Borgholio]

Wouldn't it only be a few ounces, possibly only up to a pound depending on how tough it is? Electronics these days can be *really* miniaturized...

Maybe though it would need to reach satellites considering how much of the earth is without radio coverage.

Oh that's no problem. A common two-way satellite internet communication system for home use has a dish only about two feet across and weighs about 15 pounds including the transmitter. And that's for full internet access (which many planes have already these days anyways). A GPS tracking system just has to relay basic telemetry so it could probably do with a smaller transmitter.

[Broomstick]

Only 15 pounds, ay?

It's not just weight. Everything on an airplane balances around the center of gravity, abbreviated as CG. 15 pounds at the CG is one thing, but the structure of the plane away from that point acts as a lever. Think of the force exerted by 15 pounds at the end of a 125 foot long lever. Or, for the metric crowd: 7kg at the end of a 38m lever.

For extra credit, there is also the matter of whether it's centered from side to side or displaced to one side, and whether it is above or below the plane of the CG.

This sort of thing is why whenever an airplane of any size is repainted it has be reweighed and rebalanced.

[Zaune]

Oh that's no problem. A common two-way satellite internet communication system for home use has a dish only about two feet across and weighs about 15 pounds including the transmitter. And that's for full internet access (which many planes have already these days anyways). A GPS tracking system just has to relay basic telemetry so it could probably do with a smaller transmitter.

And before anyone asks, yes, it does have to be a separate antenna. The onboard wi-fi needs to be totally physically separate from the systems responsible for controlling the aircraft, or else someone will inevitably find an exploit and use it to get up to mischief. I doubt you could turn an airliner into the world's largest R/C aeroplane that way, but you might be able to force the crew to navigate by map, compass and stopwatch because all their MFDs were cryptolockered.

[Dominus Atheos]

The type of connection you guys are discussing has already been invented. SwiftBroadband, made for internet access in private jets, should be easy to adapt to just be an always-on data relay, sending all the same data that goes into a black box to some ground location also.

The smallest and weakest antenna at "only" 200kbps (more than enough for simple telemetry and even some voice data) weighs in at less than a kilogram.

[Borgholio]

Only 15 pounds, ay?

Yep, not that big at all...dish and everything.

This sort of thing is why whenever an airplane of any size is repainted it has be reweighed and rebalanced.

Now I had no idea they were THAT precise when it came to weight balance. I can see how "only" 15 pounds might be an issue in that case if they just slapped it on without testing first.

And before anyone asks, yes, it does have to be a separate antenna. The onboard wi-fi needs to be totally physically separate from the systems responsible for controlling the aircraft, or else someone will inevitably find an exploit and use it to get up to mischief.

Oh of course. But my point was that two-way satellite data transfer on passenger airliners is already a common thing, so why not do the same to help pinpoint the location of the jet should it crash?

[Thanas]

Possible second piece found.

EDIT: Also on La Réunion, possibly a door from the airplane.

[lPeregrine]

Re: adding new equipment to all planes:

One thing that makes this a lot more complicated than it might seem is that any new addition would have to be tested and approved specifically for every type of plane that it's installed on. It's the reason why, for example, GPS navigation is a $5 ipad app or a $5000 ipad equivalent installed in even a small and simple civilian aircraft. Weight and balance is fairly straightforward, but you also have to worry about things like interference with other equipment, corrosion or fatigue life problems caused by installing it (drilling mounting holes, for example), how to isolate it from the pilot shutting it off by pulling the circuit breaker without creating an unacceptable risk of electrical fires, etc. This kind of design and testing work would be standard for factory-installed equipment on modern aircraft, but who is going to pay for it on older aircraft in use by airlines that have questionable profit margins? It's possible in theory if there's enough demand to make the change, but it's much more complicated than "just install a box in every plane".

[Simon_Jester]

This sort of thing is why whenever an airplane of any size is repainted it has be reweighed and rebalanced.

Now I had no idea they were THAT precise when it came to weight balance. I can see how "only" 15 pounds might be an issue in that case if they just slapped it on without testing first.

Well, think about it. A commercial airliner is pretty big. A Boeing 767, for instance, is about fifty meters long, with a fuselage five meters in diameter, or roughly sixteen meters in circumference, so that's 800 square meters of area to be painted. The wing area is about 280 square meters- top and bottom must be painted, for another 560. Tack on for the tail and you're looking at roughly 1400 square meters of paint.

The paint layer will probably be, oh, 100 to 200 microns thick, I'm going to estimate 150 microns.

One liter of paint can be imagined as a cube of paint ten centimeters on a side, because a liter is equal in volume to a ten-centimeter cube. Conceptually, you could then 'slice' into ten centimeters squares of the appropriate thickness like slicing a block of cheese. In that case, you'd get (100000/150) or about 670 slices of paint, enough to cover 6.7 square meters of the airplane's hull.

Covering the entire hull therefore requires about 1400/6.7 or about 210 liters of paint. Paint may or may not be as dense as water but it's about as dense, so 210 liters of paint weighs roughly 210 kilograms.

So yes, that Boeing 767 is covered in about 200 kilograms of paint. A larger aircraft would need more.

(I did all calculations in my head so they're not precise, but they'll give you a rough sense of scale)

[Batman]

Would 200kilos of paint really make that much difference in an airplane weighing upwards of 80 tons 'empty' and up to 200 fully loaded? Especially as that weight would be pretty evenly spread across the airframe so no balance issues?

[Darmalus]

Would 200kilos of paint really make that much difference in an airplane weighing upwards of 80 tons 'empty' and up to 200 fully loaded? Especially as that weight would be pretty evenly spread across the airframe so no balance issues?

I imagine it's more that they want to make sure that their "zero point" is as accurate as possible before loading it up with cargo and passengers, since said 50kg+ passengers tend to move around and probably have uneven weight distribution once seated.

[Simon_Jester]

Would 200kilos of paint really make that much difference in an airplane weighing upwards of 80 tons 'empty' and up to 200 fully loaded? Especially as that weight would be pretty evenly spread across the airframe so no balance issues?

As noted, they need to check, for the reasons Broomstick discussed. Sure, the airplane would still fly if there were 10 kilograms too much paint near the tail... but to optimize fuel economy and make the controls as responsive and precise as possible, you'd want to know about those ten kilograms, and adjust the plane's trim weights accordingly.