To Whom It May Concern. Black Box 37.5 khz Pings Are Ultra-sonic!
 

I wrote about this earlier in the forum, but now that it seems there's a good chance there's a legitimate search area, I want to reiterate that submarines and P-3's are set up for listening for submarines, ships, explosions, Say Again Machines, etc, but not optimized for the ultra-sonic 37.5 khz audible ping sent by black boxes. Maybe there are some submariners or P-3 crew that can comment about this. I've read somewhere that an 8 khz ping, would be optimum for typical submarine or P-3 equipment to hear. I know it's redundant to call a 37.5khz ping "ultra-sonic" but I want to emphasize that point. You can't hear it without a dog or down converter. If the equipment has the range, you can look at it on a spectrum analyzer. Just like radio equipment is more sensitive when tuned to a specific RF frequency, listening equipment is much more sensitive when tuned for a specific audio frequency, instead of listening to a broad range of frequencies. This may have been why AF447's ping wasn't heard or not heard consistently enough.

http://www.c-130hercules.net/gallery...1/0/5/3572.jpg

Sometimes the aircraft stays together and floats for days.

Chronus, very interesting map. Did not know it was available as normally OTH radar technology actual operational range is not public domain.

As there is not really much ( if any) traffic flying southbound in this area on that route, it should be relatively easy to look at the tapes to see if an echo existed at the time.
Or the aircraft ( if indeed there was one there ) flew exactly outside of the operational range, reimforcing the idea that this route was not chosen at random .

I have a general problem with the southern search area.

Altough we have no confirmed track across the peninsula we do have received information regarding the general direction of the aircraft. If was reported to have crossed the peninsula on a southwesterly direction to then turn to a northwesterly direction.

The above could be explained in a catastrophic event with a direct-to entry followed by a heading mode.

Hovever, to then go to a southern route you would require some human intervention. And such intervention comes very late for 'cabin survivors'.

As a consequence the southern route is not possible in the event of a catastrophic failure.

@FE Hoppy
CVR 2 hours
FDR 25 hours

It is amazing that a computer in a home you may buy for your teenage kid can outperform the storage available in a modern airliner by more than a 1000 factor.
2 hours of voice recording on a plane that may be designed to fly 16-18 hours?
In case of MH370 which may have flown for up to 8 hours and if so the voice recordings in the first two hours maybe a lot more important than the last two hours. Especially if (at least) one pilot was incapacitated for whatever reason.

The best I can gather is that the audio quality of the CVR used today is 31 kbps.
A 1TB SSD recording at 64 kbps will can store more than 72000 hours (1 channel)at twice the quality.
I believe current CVR's use either 3 or 4 channels, but even using 10 channels (some in the cabin as well), 7200 hours equals 300 days.
Based on the assumption that a CVR and a FDR use the same storage media with the FDR yielding ~12 times duration of a 4-channel CVR a 1 TB SSD would store 9000 days of data (the life of most airframes) ... all for under $1,000 (excluding DAQ which would likely be the same as current recorders).
Using the same storage media (1TB SSD), the use of 10 video cameras in full motion mode would record 40 hours of video.

Time to use current technology, methinks

Hunter, Inmarsat puts it on the red arc at 0811. That's not consistent with traveling in a straight line SW over Malaya. Either the SW report over Malaya is wrong, or extra turns were required.

In either case, I'd bet on Inmarsat being right, and the zigzagging over the NE Indian Ocean being a bit suspect.

That was me in the decompression chamber with a compatriot who appeared to be unaffected until we checked - remember this was just over 30 seconds - he was writing perfectly neat garbage and was not 'responsive' to the instructor who got his O2 back on rapidly. I cannot see anyone at 35,000 with hypoxia doing/saying anything sensible after a few seconds.

It would be most instructive to know what the controller said to the crew, a chatty non-standard handoff could get an "alright goodnight" in response.

No correction here, but compliments on the great tomato teaching analogy. CDMA would be better for the satellite to use than time division, since propagation delay does not affect it as much, since the bits know how to put themselves back in order at their destination, since they are encoded in a Walsh Code. Of course, it's not easy to upgrade a satellite as well as the many customer transceivers, unless they have an up-loadable modulation format. So it's probably just academic. Maybe the next set of satellites and customer equipment will have CDMA modulation. Of course, the very nature of time division multiplexing may make it easier to use the shift in the spaces between the bits, as the customer moves, for tracking purposes.

My point is the second one, why are they searching at some calculated end of the arc rather than along it. It isn't known what speed the aircraft was flying at. They've highlighted a search area for Australia that is at the end of the aircrafts fuel range, at some assumed cruise speed. All they know is that the transmissions were received somewhere in the arc (north or south) during those time periods. It could have been circling a single point and remained in the width of the arc and the width is not a line, it has a width due to the lack of precision of the sat data. Remember the arc is NOT a track of the aircraft. The entire arc should be given the same POD until proven otherwise.

Now I am more than confused.

The reports are that the left turn brought the aircraft in an SW direction before turning NW after crossing the peninsula. The zigzag was never reported and is contrary to indonesian reports. None of this says anything about the 0811 ping.

My point is that the northern location would be consistant in an catastrophy assumption. But it is not possible in a southern location as someone would have to get the aircraft out of the NW heading.

Size is not everything dear!
 

State of the art technology does not have to be safe to be installed in your teenage kids' PC. Failures are an inconvenience not a disaster.

Keeping safety critical systems safe means they may run a generation (or two) behind the latest capabilities. That is not a bad thing.

Let's face it, using "current technology" batteries in aircraft has created a few issues recently.

ULB Detection
 

Back in one of the earlier AF447 threads, auv-ee explained in detail the detection range of the 37.5kHz ULB pinger.

The maximum detection range is 2 - 3km, and in rather calm sea conditions. Less than 1800 meters will provide a 90% or better chance of detection. All this is described in detail by one who knows and has the experience to go with it.

Hunter,

While it could be anywhere on the red arc at 0811, Inmarsat sensibly curtailed the arc at a spot in the Indian Ocean that is the number of flight hours multiplied by a reasonable speed from the South China Sea. They presumably have several earlier hours of angle measurements too, which would be consistent with that.

It seems unlikely to me that the Australian government would make such a big deal about going to look in that oceanic box unless they had some good information that looking in that box was likely to pay off.

The biggest problem with the northern route is that someone somewhere should have seen it co,ing, whereas going south there's nothing to bump into.

The earlier Inmarsat ping angles would show whether or not a steady straight flight into the void was consistent with them. I trust the heavy Australian search is based on sound information, although their released pictures of the "ocean objects" are very whitecap-looking to me. The radar shenanigans and turns over SE Asia all seems to be pretty random.

Methinks you are offering a solution in search for a problem, just like numerous others here. As for flight deck access, for obvious reasons, no one is going to discuss this in public. Big surprise there. Yawn.

@Hunter58
The piece of the jigsaw that I think you are missing is that at the press conference a day or so back, the Malaysian official equivocated spectacularly when asked to confirm that MH370 had in fact made the NW turn and passed through or toward the subsequent waypoints. He didn't actually deny it, but was as near as possible to doing so.


So, it appears that all that is confirmed is that the aircraft crossed the peninsular heading SW, and all the conclusions and inferences drawn from the implication of deliberate human action in turning the aircraft, except for the initial turn back toward peninsular Malaysia, are, in fact, baseless.

basic facts
 

@richardgb

changes in altitude -- main source was the big Times story (35K --> 42K -->23K), seems to be extrapolated from Malaysian primary radar, and has been critiqued as not reliable. second source was Straits Times article about plane flying low at 5K feet to avoid radar. This was echo-chambered by many news outlets. If you look at the original story, the reporter only invited some Malaysian military guys to speculate, then wrote the story with the hypothetical as a fact. not reliable.

UPDATE: 3/23, CNN goes nuts with *their* altitude scoop, which is that, extrapolated from Malaysian primary radar, the flight turned back and dropped to 12,000 feet between 1:19 and 2:40 (speed and timing of drop not specified). This, imo, is simply another version of the altitude-change-calculated-from-primary-radar story, and not new news. Seems to depend on which analyst at which remove from the investigation is leaking. Of most interest here is the "2:40" time. 2:40 was a time we saw in the very first news stories, but then the Malaysians consistently said the flight dropped off their primary radar at 2:15. So what, exactly, correlates to 2:40, and why is that time making a resurgence?

following pre-programmed way points (same as zig zag tracks) Again, a big NY Times headline. All subsequent reporting and statements from the Malaysian pressers have only made this more confusing. If there is any hard data that a new flight plan was entered in the cockpit computer, it has never been directly stated or confirmed. Instead, experts seem to be extrapolating from the primary radar track, and also assuming the new flight plan was transmitted in the 1:07 ACARS burst. But no source has verified that speculation, even in news articles I've read that claim that happened.

UPDATE 3/23, Malaysian Ministry of Transportation confirms "The last ACARS transmission, sent at 1.07am, showed nothing unusual. The 1.07am transmission showed a normal routing all the way to Beijing."

fuel load on departure Normal fuel load, enough to get to Beijing with an hour to spare. Yes, reliable and verified directly in Malaysian presser. This is a fact they stated clearly and proactively and did not waffle on. I trust this as fact.

Per Bloomberg:
"The Boeing 777 was carrying 49.1 metric tons (54.1 tons) of fuel when it departed Kuala Lumpur, for a total takeoff weight of 223.5 tons, according to Subang Jaya-based Malaysian Air."

whether the last verbal communication was before or after the initial divergence from the flight plan At least in the U.S. the media went to town saying it was after, and taking this as proof of pilot deliberation. Unfortunately, at the following day's presser, the Malaysians said reports were inaccurate, but declined to provide a timeline of these events, and have deflected all lines of questioning about that critical series of events by saying their main priority is to find the plane. Upshot: we don't know. The investigators surely do, but are they leaking, and to which reporters?

satellite ping data and the consequent assumptions about the two arcs of likely location Satellite ping data is very solid fact. Data has been independently analyzed by NTSB and British Accident Board, who came to identical conclusions about the probability arcs. Further, the Australian SAR head in his presser said that they are leveraging ALL of the pings (not just the final one) in creating a probable flight path. That plus wind, current, fuel, speed, and other calculations narrowed down the southern search area. imo you'd need to be a major conspiracy theorist to believe everyone is colluding on a fake ping narrative.

radar or lack of radar returns Fact is secondary radar handoff from Malaysia was 1:19, and transponder data ceased at 1:21. Malaysian military primary radar tracked the plane (as a blip) until 2:15 when it went out of range back toward the west. They did this not in real time, but upon reviewing a recording. As for Vietnamese civilian radar, there was a report that they alerted the malaysians that the plane had turned back, but when they noticed this or when they alerted is not clear. The Thais came forward only a couple of days ago to say their primary radar had also tracked the plane west. India says they didn't see it. China says they didn't see it. Other countries are cooperating in examining their radar, but that will not be made public, per the pressers, to ensure their national security capabilities.

Law is the country the plane crashed in leads the investigation. The plane manufacturer and airline send consultants. In international waters I think there''s an international investigation protocol. The Malaysians headed this so far because it's their airline, the plane took off from their country, and nobody knew if it crashed or where.

P.S. If subsequent posts take issue with any of the above, I'm happy to edit it. I'm really keen on "what exactly is fact" versus inference, speculation, or spin

awblain

I am sure that neither India, Nepal or China would like to admit that they missed an airliner flying a constant heading with their 'elaborate' air defence radars. However, just because they could be loosing face does not give any reason for not looking. Until now in this whole story everytime the media attention was on one side it proved to be the other.

If inmarsat is so confident on their findings, why do we not have a public analysis of their conclusions?


Despairing Traveller

and which part was the official maneuvering about? The general direction or the zig zagging which they never confirmed in the first place? There is quite a difference in the two.

That's assuming the people listening for it have the proper or properly tuned equipment! BTW: Thanks for the link. He definetly explains the transmission end of it. I'm just not sure all the people listening for the 37.5 khz ping of MH370's black box locator beacon, have the optimum equipment to hear it anywhere near the maximum specified distance!

Satellite pings could confirm flight path
 

Although the only data point that appears to be associated with an individual handshake between the Inmarsat satellite and MH370 is distance (or angle to the satellite), that information is quite useful. From most news accounts, Inmarsat had data for the entire time MH370 had power, with each successive handshake approximately 60 minutes apart. If that is the case, they should have one at about the same time the plane’s transponder stopped working (approximately 43°). From that point, you would have very different data depending upon the path the airplane took.

For example, if the plane did a 180 and turned around, you would have the following data:

2:11 44°
3:11 45°
4:11 46°
5:11 46°
6:11 45°
7:11 43°
8:11 40°

However, if the plane turned westward and crossed the peninsula and skirted the Northern part of Sumatra before turning South, you’d have something like the following:

2:11 49°
3:11 54°
4:11 54°
5:11 52°
6:11 49°
7:11 45°
8:11 40°

Obviously, I don’t have the actual data and the numbers are probably off a bit but you get the general idea. Knowing the satellite data will allow you to narrow down the potential flight paths. I’m sure that is what the NTSB has used (along with a lot of other data) to generate the paths shown on the maps the Australians are using to show the search areas.

Just to add to Hunter and Pontius Navigator's post directed toward Arearadar's reply that included

It is not as if we have only 1 Country involved here, either.

You have Thailand on the other side of the border showing apparently the same flight path across the peninsula. They indicate they never lost sight of the re-appearing plane (well, at least for any considerable amount of time) and say it never entered their space, basically skirting the border.

That is 3 countries (Malaysia, Vietnam and Thailand) combined showing the plane going dark (all 3), turning around (at least 2 - Vietnam and Malaysia), and showing back up off the Peninsulas coast (suspected 2, but at least Thailand) with a total time frame of that series of events at about 10 minutes. Then 2 of them are able to put together a path across said peninsula starting at that time; 2 identified paths that apparently line up with each other. Meanwhile no plane continued on the flight path MH370 was on into Vietnam territory and no plane crashed into the Gulf.

I myself am fairly confident they would be able to figure out with a very high degree of certainty that it is probably not some other 'unidentified' stolen or mysterious similarly sized plane flying around the same areas at the same times ...well, short of them having WashOut and Tug at the helm, I guess.