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Malaysian Airlines MH370 contact lost

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Malaysian Airlines MH370 contact lost

Old 21st Mar 2014, 15:49
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Galaxy nope
but it depends on what happens and what order it happens when the engines flame out...and what speed the generators go off line.
It could of course slow up in altitude hold until they stop producing usable electrical and hydraulic power.
Since there have been several theories (reports?) of varying altitude I am assuming that there wasn't anyone flying her.
What I was suggesting that if the crew were incapacitated (or incapable of controlling the aircraft due to electrical problems) then for the aircraft to stay airborne for 7 hours and then crash it would probably descend in a controlled fashion and not nose dive at 10000fpm+ as has been suggested.
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Old 21st Mar 2014, 15:49
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MH370's location

Originally Posted by onetrack
Chances of finding the aircraft in the Southern Indian Ocean when 14 days have passed and there's only a vague idea of its LKP? - Very, Very Low.
IF current search area is most likely...

The average depth of the Indian Ocean is 3,890 m (12,762 ft). Its deepest point is Diamantina Deep in Diamantina Trench, at 8,047 m (26,401 ft) deep located about 1,125 km west-South-West of Perth.
Light penetrates up to 660 feet (about where bathyl zone starts – it ends at about 6600 feet where temp drops to 4 degrees C)
The abyssal zone extends from 6600 feet to the bottom about 20,000 feet where the trenches begin. Pressures here range from 200 to 600 atmospheres. The waters though are serenely still.
(Note: The deepest descent by humans was in 1960 by Trieste (to bottom of the Challenger Deep in Marianas Trench in Pacific O – 35,810 feet – pressures of 16,000 pounds/sq inch – 1000 x sea level).

Re AF447, debris and bodies, still trapped in the partly intact remains of the aircraft's fuselage, were located in water depths of between 3,800 to 4,000 metres (2,100 to 2,200 fathoms; 12,500 to 13,100 ft). The Bayesian search theory was used by Metron to map the probable area. AUVs with side scan sonar were then used and found a fairly compact debris field 200x600 metres. The US ROV, Remora 6000, in its first dive found the FDR.
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Old 21st Mar 2014, 15:52
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Originally Posted by Speed of Sound
This information seems to have been missed by most posters on here. That would suggest to me that hourly pings were actually recorded and not overwritten.
this was confirmed by AMSA on day 2 of the aussie searching and today by the malaysain minister in the daily briefing.


It is not news
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Old 21st Mar 2014, 15:57
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Since there have been several theories (reports?) of varying altitude
Apart from the claimed PSR information of a climb to FL450 and a decent to FL295, there has been no confirmed reports of any varying altitude.

All we can say for definite is that if it continued flying for over 7 hours then most of that time must have been at or above FL300 for the claimed fuel on board.
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Old 21st Mar 2014, 16:18
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Originally Posted by Speed of Sound post #7036
"We couldn't say what direction it had gone in, but the plane wasn't standing still because the signals were getting longer, i.e. further in distance from our satellite."

Inmarsat Senior Vice President Chris McLaughlin
- is there any link to this statement? Does Inmarsat know in detail what was happening to the signal elevation during the 7 hours? ?Assuming the reception angle is referenced to the earth vertical? I would assume from the above 'quote' that the elevation was increasing at some latter stage. If the information is refined enough it might be possible to re-create multiple paths of likely routes which when meshed with start pos would surely yield some clues? Initially we were told is was a '40 degree' signal, but that does not appear to be the whole story. Logically the elevation would decrease during the supposed 'turn back' and 'Malacca transit' - then what?
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Old 21st Mar 2014, 16:20
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HMS Echo

Little off topic but let us not get carried away with the capabilities of HMS Echo....

I spent 3 years on board and her sister ship as a civilian contractor providing support for the survey equipment and teaching Navy operators how to use it - (yes as a civilian - really!).

The vessel is fitted with survey equipment for up to 1000m depth. It is great at finding wrecks. A sidescan sonar can only see a 200m wide swathe and you can only survey at 4.5knots. Her hull mounted multibeam will see a much larger swathe, but it is not designed for detecting objects - just changes in seabed. The 'hit' rate per metre squared is too low.

While Echo is a valuable asset, but it is not magic and is limited by the equipment. What may be of more use is her ability to act as a command platform.

I now work as a Survey Party Chief running geophysical surveys (as well as a flight instructor) - so I do know this industry as well as flight instruction.
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Old 21st Mar 2014, 16:20
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Hunt for Jet Switches to Visual Search as Radar Empty - Bloomberg

The engineers at Inmarsat were able to validate their estimates of the plane’s location by matching its position at 1:07 a.m., when it sent a burst of data through its Aircraft Communications and Reporting System, McLaughlin said. That final transmission on Acars included a GPS position that was used to calibrate the other estimates, he said.
Does that mean, the final ACARS transmission was already made via SATCOM?

If the ping at 1:11 was used for calibration, wouldn't it have been better to do the calibration against the position from secondary radar at 1:11. Transponder was switched off at 1:21.

That statement only makes sense if ACARS at 1:07 already went via SATCOM, which would mean ACARS via VHF was deliberately? disabled before.
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Old 21st Mar 2014, 16:24
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CodyBlade
why do you want to know the answer to this question?
Probably best answered by the old saying "It is better to remain silent and be thought an idiot than open your mouth and dispel all doubt." I fear that today is the day Razoray forgot to borrow the family brain cell.
With any luck security services will be monitoring this thread and will be paying special attention to Razoray's posts.
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Old 21st Mar 2014, 16:26
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pings, acars and upgrades

Originally Posted by BOAC
is there any link to this statement?
Here's one
Malaysia Airlines Flight MH370 Would Have Been Found If Communications Box Had $10 Upgrade

includes interesting bit about $10 upgrade to ACARS transmissions to send black box data in real time!
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Old 21st Mar 2014, 16:27
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That statement only makes sense if ACARS at 1:07 already went via SATCOM, which would mean ACARS via VHF was deliberately? disabled before.
Correct me if I'm wrong but isn't the VHF ACARS transmission uplinked from a ground station to the Inmarsat anyway so the fact that it is eventually received by the satellite doesn't necessarily mean it was sent by SATCOM?
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Old 21st Mar 2014, 16:29
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ncludes interesting bit about $10 upgrade to ACARS transmissions to send black box data in real time!
It's not sending black box data, just position updates including GPS coords more frequently.
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Old 21st Mar 2014, 16:29
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odd

"We couldn't say what direction it had gone in, but the plane wasn't standing still because the signals were getting longer, i.e. further in distance from our satellite."

Inmarsat Senior Vice President Chris McLaughlin
That's an odd choice of a word. I assume that by longer he means the time delays between each hourly ping, in milliseconds. If so, it is wrong to construe that delay with distance alone. Ping time can increase for multiple reasons not related to distance. One obvious confounding factor is interference of some type.

What would be interesting to do is some type of statistical smoothing. For example, if the plane was flying a consistent speed one would expect the increasing ping delay to follow a consistent, not random, pattern. OTOH if the ping delays were increasing at an increasing rate then distance alone might not explain it. The forensic calculations get complicated quickly having to take into account so many parameters. I'm going to assume that they go it right and have had many different eyeballs look at it. But I do not think we should treat the result of such calculations as a certainty, more like an educated guess.
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Old 21st Mar 2014, 16:33
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Originally Posted by Mountain Bear
What would be interesting to do is some type of statistical smoothing. For example, if the plane was flying a consistent speed one would expect the increasing ping delay to follow a consistent, not random, pattern. OTOH if the ping delays were increasing at an increasing rate then distance alone might not explain it. The forensic calculations get complicated quickly having to take into account so many parameters. I'm going to assume that they go it right and have had many different eyeballs look at it. But I do not think we should treat the result of such calculations as a certainty, more like an educated guess.
- don't forget a ?sinusoidal? rate of change if the TX crosses the concentric signal elevations.

brika - no more help in that link!
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Old 21st Mar 2014, 16:34
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They have a very accurate position at 07 due to the VHF ACARS transmission. They use that datum with the next ping to work out the return time at that known range. High school maths then allows you to work out future ranges based on ping return times.

It's not rocket science although they are capable of that too!
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Old 21st Mar 2014, 16:35
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Correct me if I'm wrong but isn't the VHF ACARS transmission uplinked from a ground station to the Inmarsat anyway so the fact that it is eventually received by the satellite doesn't necessarily mean it was sent by SATCOM?
I'm struggling with the concept too, but imho Chris McLaughlins statement only makes sense if there was some kind of SATCOM between the inmarsat satellite and the A/C, at 1:07 which was used to calibrate the signal return path between them.
An ACARS message between ground station and satellite wouldn't doe any good to calibrate the path between satellite and A/C transceiver.

Last edited by OleOle; 21st Mar 2014 at 18:25. Reason: clarify what was calibrated
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Old 21st Mar 2014, 16:35
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ACARS update

Yancey Slide #7045

IBT said "You really do need to know the height, distance, direction and a record of what has been going on the flight deck in a regular burst every 15 to 30 minutes," said McLaughlin. "If the box had been configured to send out these bursts, we would have located the plane by now."

Of course one also needs to prevent someone turning off transmissions otherwise its not am improvement

Last edited by brika; 21st Mar 2014 at 16:39. Reason: last line added
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Old 21st Mar 2014, 16:41
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MountainBear:

By "getting Longer" he is referring to the fact the ping sends a timestamp with its ping, and the satellite adds its own timestamp on arrival; so in this case the difference between these timestamps (in milliseconds) would be increasing, implying a longer distance between the sender and the satellite.
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Old 21st Mar 2014, 16:42
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I think some are getting confused between the INMARSAT link and ACARS... there isn't one, except if you pay for a certain service the SAT link will carry ACARS data.

REMEMBER folks the SAT transceivers on the aircraft are also voice capable, and the pings are used as a "stay-alive" status at the SAT-end of this link. In other words if the crew decided to make a SATCOM voice call, the satellite needs to be ready to relay the message.

What he's inferring I believe is that the last ACARS transmission DID include precise positional info, so the 1.11 SATCOM ping will closely correlate with the 1.07 ACARS report, and from thence the following pings can be traced/located (at least to ping arcs).
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Old 21st Mar 2014, 16:43
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They have a very accurate position at 07 due to the VHF ACARS transmission. They use that datum with the next ping to work out the return time at that known range. High school maths then allows you to work out future ranges based on ping return times.
But it doesn't make sense to take the GPS position at 1:07 for calibration, if for the next ping - which probably was exchanged at 1:11 - secondary radar position from 1:11 was available. Why then take the GPS fix from 4 minutes earlier and not the SR fix from that same minute ?
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Old 21st Mar 2014, 16:45
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Inmarsat

Megyn Kelly´s interview with Mr. Chris Mclaughlin, Senior Vice President at Inmarsat; the most articulate / informative one to date.

Satellite company official speaks out on tracking missing jet after it lost contact | Fox News
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