Malaysia Airlines Loses Contact With 777 en Route to Beijing

[Highkeas]

[QUOTE=guamainiac;621520]................. Hard to believe that no outside credible (as they can be), agencies have seen the "hard data" ............................QUOTE]

My understanding was that the search areas based on the ping data were developed by the UK AAIB in conjunction with other credible agencies (such as NTSB, Australia, and perhaps Boeing).

My experience having worked on failure investigations is that the release of information to the public is usually restricted to the lead authority in the investigation.

[guamainiac]

Sorry Highkeas, I've been off for awhile and some recent posts have mentioned this notion. I didn't do adequate catch up reading for sure.

Still, I have to thoroughly disagree with Gabe's proposition in his #5. I think a high speed crash that destroys the airframe would release lots of small and pliable (especially soft), debris such as towels, napkin or clothing and luggage if at sea; if on land in a remote jungle area it would of course make it hard to see if it went in straight and fast. I'm thinking of the small "footprint" of the 9-11 crash over Pennsylvania or especially that old Florida crash in the Everglades where it seemed smaller than the average suburban homes lot.

Perhaps that is a clue, an impact in a remote marsh however, then the beacons would be easy to detect?

[kris]

4- beyond the boundary of the search area ... yes indeed, as per the "4 ping thing" and how credible those are which is right back to square one. Hard to believe that no outside credible (as they can be), agencies have seen the "hard data" to verify any reasonable possibility they served as a valid base to establish such an extensive search?

I'm not surprised. The Doppler data most probably doesn't come from a satellite service company, Inmarsat has no interest in gathering such information. There is no Doppler shift between Earth stations and geostationary IOR satellite, yet they admitted they had to correct for this shift.
This means the data comes from NSA or similar source. Why would they want to publish raw data, to make sure everyone knows their capabilities?

[Highkeas]

I'm not surprised. The Doppler data most probably doesn't come from a satellite service company, Inmarsat has no interest in gathering such information. There is no Doppler shift between Earth stations and geostationary IOR satellite, yet they admitted they had to correct for this shift.
This means the data comes from NSA or similar source. Why would they want to publish raw data, to make sure everyone knows their capabilities?

I assume the transmission data is recorded so times and Doppler shift is inherent in that data and can be easily determined with instrumentation. Probably there is normally no need to mine Doppler data.

I hope the tracking analysis, including methods and analysis, will be included in the final investigation report.

[Evan]

I hope the tracking analysis, including methods and analysis, will be included in the final investigation report.

Or the interim report. We might never see a final report.

[starchyme]

a case for unsolved mysteries

Not only can they not find the plane, they cannot find the data used to determine current search zones. This sounds like a lost case in total. Before everyone starts to look bad, maybe call it quits, sad for the families, but things are not looking up either way.

http://edition.cnn.com/2014/05/15/world/asia/malaysia-missing-plane/index.html?hpt=hp_t3

[Gabriel]

5- seems to defy known physics?

The supersonic part maybe.
While these planes can concivabily achieve slightly supersonic speed at a high altitude dive where the air is thin, I don't think that it would remain in one piece at supersonic (or even close to sonic) speeds at low altitude.

In the high flight levels, Mach 1 would equal something slightly more than 300kts IAS (in fact the TAS would be about 600kts) so, with a Vmo of 330kts, the "background" aerodynamic forces (those that would still be there after removing the trans/supersonic effects) would be in the manegable range for the plane, but at sea level Mach 1 is above 660kts, way beyond the envelope even after considering margins.

Now, a dive into the water at say 400kts and a high penetration angle will leave very little larger than say 5 inch.

[BoeingBobby]

The supersonic part maybe.
While these planes can concivabily achieve slightly supersonic speed at a high altitude dive where the air is thin, I don't think that it would remain in one piece at supersonic (or even close to sonic) speeds at low altitude.

In the high flight levels, Mach 1 would equal something slightly more than 300kts IAS (in fact the TAS would be about 600kts) so, with a Vmo of 330kts, the "background" aerodynamic forces (those that would still be there after removing the trans/supersonic effects) would be in the manegable range for the plane, but at sea level Mach 1 is above 660kts, way beyond the envelope even after considering margins.

Now, a dive into the water at say 400kts and a high penetration angle will leave very little larger than say 5 inch.

I concur 100%!

[TeeVee]

Now, a dive into the water at say 400kts and a high penetration angle will leave very little larger than say 5 inch.

not sure i believe the 5 inch part.

[Traumflug]

Now, a dive into the water at say 400kts and a high penetration angle will leave very little larger than say 5 inch.

If you remember car crashes into a concrete wall you'll remember these cars usually get crushed, but stay in mostly one piece. Also, the rear parts have a deceleration distance of almost the length of the airframe, so they probably won't even severely crush. And there are a number of quite stable parts, like the gear and the inners of the engines.

That said, finding 10 feet long parts isn't exactly simple, either.

[Traumflug]

Wouldn't noisemakers have voltage regulation and crystal controlled oscillators to have a very stable frequency?

Yes, that's typically the case. Quartz crystals either swing at the right frequency or they don't swing at all. There are resistor/capacity oscillators, too, but they're usually used only when trying to squeeze away another few percent of the costs of a $3 device.

[Gabriel]

If you remember car crashes into a concrete wall you'll remember these cars usually get crushed, but stay in mostly one piece. Also, the rear parts have a deceleration distance of almost the length of the airframe, so they probably won't even severely crush.

There are so many factors that I don't know where to begin:

Energy:
A high speed car crash is perhaps 100kts / 115 MPH / 185 kn/h.
A 400kt crash is not only 4 times as fast, but because energy goes with the square of speed, it involves 16 as much energy per unit of mass.

Material:
Aluminum vs steel. No, I will not say that steel is stronger than aluminum. Volume by volume, it is. But pound bay pound, it isn't.
However, the melting point of Al is about half that of steel.
You'll see: deforming a material makes heat. If you bend a regular steel several times until it brakes, you can feel that it got quite hot. It can actually hurt. And that process took several seconds, perhaps a minute, so the heat had time to dissipate. If you did all that work in one second, the heat build up would be much higher. Now consider the energy of a 400kts crash, and when I said "vaporized" it might have been not such a left-field exaggeration. I don't know for sure, but I think that a good part of the aluminum might melted in such a crash.

Crashworthiness:
Cars are designed with crumpling zones to absorb energy in head-on crashes. Transport category airplanes aren't.

Deceleration of the rear:
You are wrong. The rear may not even "realize" (force-wise) that the forward par is crashing. Very high speed deformation of the materials is a phenom very different from slower speed deformation. When you apply a force to one zone of a structure, the stress at other zones doesn't appear instantly, because the stress travels along the structure at a propagation speed. If the plane is traveling faster than that propagation speed (and, at 400kts, let me bet my wallet that it would be), then the rear would not know that the plane is crashing until the rear itself crashes still at full speed. Especially since the plane is made of aluminum, which has a elastic modulus (wave propagation speed is proportional to it) of 1/3 of that of steel.

Experience:
Ok, enough theory. Let's go to practice:
Have you ever seen any big-plane high-speed high-angle crash where the plane gets crushed but stays mostly in one piece? Or where the rear remains in any recognizable form, let alone "not severely crushed"?
I suggest you to google images of Austral 2553 and United 93.

And there are a number of quite stable parts, like the gear and the inners of the engines.

That said, finding 10 feet long parts isn't exactly simple, either.

With that I agree. That's why I've said "very little larger than say 5 inch" (very little means not much but yes something) and "with a few isolated bigger parts (a black box here, a turbine disk there...) that are not outstanding enough to stand out in the sonar images".

[Gabriel]

Yes, that's typically the case. Quartz crystals either swing at the right frequency or they don't swing at all. There are resistor/capacity oscillators, too, but they're usually used only when trying to squeeze away another few percent of the costs of a $3 device.

Well, but...

The manufacturer of the underwater locator beacons (ULB), that were mounted to the flight data and cockpit voice recorders of MH-370, specified their ULB would transmit ultrasonic pulsed sounds at 37.5kHz +/- 1kHz at 160dB (re 1µPa). After a period of 30 days the ULB would still transmit at that frequency at 157 dB. The manufacturer did not publish any data beyond 30 days (certification criteria). Other manufacturers specifying their ULBs also at 160dB initially and 157dB after 30 days state the ULB would still transmit after 90 days though at around 150dB, the frequency drift may exceed 1kHz.

http://avherald.com/h?article=4710c69b&opt=0

And there were strong talks that MH was way overdue with the scheduled replacement of the batteries of the ULBs. So the batteries might have been quite low even before take-off, let alone after 30 days of transmitting.

[brianw999]

Just to bring home what Gabriel is saying. This....




....turned into this.....




It doesn't bear thinking about what happened to the passengers. Just thank God that it was over in an instant.

RIP.

[Gabriel]

I suspect that the black boxes are on a very specific frequency and that the oscillators are crystal controlled to keep the frequency very exact, regardless of battery voltage, temperature, etc. So I suspect it is highly unlikely that the frequency would have changed.

While I'm glad that they have considered that these ping contacts might have been from the missing flight, I think they may have put too much weight on the "credibility" of these 4 pings contacts. They may have narrowly focused too much attention and resources too early on, instead of focusing on doing more broader searches for blackbox noisemakers/pingers.

Since the 4 "credible" ping contacts were on the wrong frequency, it suggests that they are probably related to other phenomena. Natural sounds, ping noisemakers for other purposes (IE tracking tagged wildlife, tracking tagged scientific equipment, etc.)

I'm very suspicious that the aircraft is not in the immediate area. The reports of "credible" pings, raised my hopes that the aircraft would be found in a few weeks. I doubt the credibility of those pings, so I now suspect that the search may last years and the aircraft may never be found.

If they would have released recordings of the ping contacts early on, it's unlikely that they would have held up to public scrutiny from the scientific community. Not being on the right frequency is a big yellow flag. It's quite likely that the pulse rate and waveform is also inconsistent with a blackbox pinger. I still haven't seen any recordings released of these 4 alleged "credible" ping contacts.

Well, there was some information obtained live by reporters aboard Ocean Shield:

https://www.youtube.com/watch?v=el61KlF-NWs

And an interesting analysis of what's seen and heard in that video by someone that claims being an expert on this field:

http://iheartmatlab.blogspot.com.ar/2014/04/analysis-of-suspected-mh370-pings.html