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Malaysian Airlines MH370 contact lost

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Malaysian Airlines MH370 contact lost

Old 13th Mar 2014, 14:03
  #2741 (permalink)  
 
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Proposed Search Location

I worked on flight profiles for avionics system tests at Naval Air Test Center (Pax River) for a couple years back in the late 1980s. Based on the reports I've heard, my analysis is as follows:

' ' Point S1 - Last ATC contact
txtStartLatitude = "6.9208"
txtStartLongitude = "103.5786"

' Point S2 – Contact, ADSB system (web track FR24)
txtStartLatitude = "6.9208"
txtStartLongitude = "103.5786"

' Point S3 - Last ATC contact, ADSB system (web track FR24)
txtStartLatitude = "6.9208"
txtStartLongitude = "103.5786"

' Sanga Mercur Oil Rig - known position
txtStartLatitude = "8.3667"
txtStartLongitude = "108.7026"

' Oil rig (Sanga Mercur Oil Rig) sighting report was:
' 265 - 275 bearing, high, minimal lateral velocity, on fire
' Plane had to be below 15,000 ft to not be on SGN ATC

' Maintaining 65 deg course from S4, gliding @ 7:1 on fire?
' max range = 17.3 nm
' could have just reached the rig if turned toward it immediately, but
' rig was only 15 deg off to right so might have maintained course since
' that's where SAR would look (assuming SAR doesn't know about rig)
' Oil rig report: 265 - 275 bearing, high, minimal lateral velocity,
' on fire. Plane had to be below 15,000 feet to not be on SGN
' (Ho Chi Minh City) ATC as reported. Not sure how oil rig bearing was
' determined. If phone more accurate, but if just memory from rig true
' north, then maybe +/- 25 deg instead of +/- 5 deg.
'
' Point S4 - Location at oil rig sighting (assuming due west as reported):
txtStartLatitude = "8.3667"
txtStartLongitude = "108.4186"

' Maintaining 65 deg course, with 7:1 glide ratio.
' Not sure on glide ratio, 7:1 is for 747 (my memory).Also that's max
' with optimal AOA. Some time would have been used before attempting
' max glide and on fire (damage) would have probably reduced it.
'
' Point S5 - Final point (end of glide – crash/ditch) is at:
txtStartLatitude = "8.4885"
txtStartLongitude = "108.6825"

Obviously, there is some uncertainty in this position. I'm not sure about the FR24 system (I believe it extrapolates minute to mintute) Points (S2 & S3). I'm also not sure about the oil rig sighting bearing and distance (S4). Best guess on my S5 estimate uncertainty is +/- 15 nm. We probably have subs scanning gulf bottom by now (as well as ships) and they will probably find it soon.
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Old 13th Mar 2014, 14:04
  #2742 (permalink)  
 
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@ TURIN

Totally agree - once out of LOS radio range, ACARS would switch to direct Sat link.
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Old 13th Mar 2014, 14:07
  #2743 (permalink)  
 
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...or it would switch to HFDL....
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Old 13th Mar 2014, 14:10
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..a fisherman with a bit of plastic is likely to be the first to shed light on the l

Good. Common sense is not totally dead.

One caveat: anyone notice,what was a semi-strange answer for a basic question on a civilian jet's NAVCOM equipment on Day 2 or 3.

"Asked to detail the communications devices aboard the missing jet, Boeing spokesman Doug Alder said, "Itís not appropriate for us to discuss that right now."
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Old 13th Mar 2014, 14:12
  #2745 (permalink)  
 
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MountainSnake
"On 5 June 2009, the French nuclear submarine …meraude was dispatched to the crash zone, arriving in the area on the 10th. Its mission was to assist in the search for the missing flight recorders or "black-boxes" which might be located at great depth.[93] The submarine would use its sonar to listen for the ultrasonic signal emitted by the black boxes' "pingers",[94] covering 13 sq mi (34 km2) a day. The …meraude was to work with the mini-sub Nautile, which can descend to the ocean floor."

Source Wikipedia.

Are they trying to listen to the FDR/CVR pingers in the area where the transponder stopped emitting? Maybe they are but I have never heard anything about yet.
There are a lot of naval and air assets out there. Some have an anti-submarine warfare capability and with it, an underwater acoustic capability. The areas west and east of the Malaysian peninsula so far searched have consisted of shallow water. Any continuance beyond the Straits of Malacca starts to run off the continental shelf to deeper water in the Indian Ocean.

Shallow water makes for a notoriously difficult acoustic environment. Those waters are chock full of fishing vessels. Man made noise and natural noise in the water adds to the ambient noise, which will be much increased over that of an open ocean environment. Reverberations will be rife. There will be surface reflections and bottom bounce (depending what the bottom is made of).

In deep water, sounds spread spherically, greatly dissipating the intensity. Shallow water, constrained by the surface and sea bed, causes the sound to spread cylindrically, meaning in a given volume the noise is greater. It's logarithmic and I can't be 4rsed digging out my old notes! 10Log versus 20Log.

That said, the shipping noise is low frequency whereas sonic locators on Flight Data Recorders is not. Regardless of the frequency, ambient noise is still a factor and higher frequencies are subject to greater attenuation than low frequencies.

In the Air France 447 case, the location was open ocean; much quieter acoustically and a submarine could manoeuvre in the deep water there. Submariners are notorious liars about where they are and where they've been but if they tell you they are loath to go anywhere a prang might ensue, I'd (guardedly) believe them. They certainly don't like shallow water.

They could use a surface vessel with a decent SONAR suite to listen for the location device. To cover any area AND listen is almost mutually exclusive. They may need to sprint and drift, otherwise their Own Ships Noise (OSN) may mask what they're listening for. Otherwise, drop sonobuoys from fixed or rotary-winged aircraft. That might do it.

Look, an acoustic search really requires a half decent datum to start with. An acoustic search of the South China Sea or the Indian Ocean, or even a corridor of the Indian Ocean, is really not a practical primary search tool. Searching for this aircraft now, entering the sixth day with so many false starts, will have left any traces on the surface in a much diminished state.

I flew SAR on Air India 182 back in 1985. I was an acoustic specialist on my Nimrod Maritime Reconnaissance crew. We dropped buoys but heard nothing. The water there was over the 1000fathom line and was "quiet". Plus we dropped buoys at each of the 2 datums of wreckage on the surface, so we were as near to the source as one could be, under the circumstances. We heard nothing. To be fair, sonic location devices then were in their infancy and I've no idea if the Air India 182 aircraft had been fitted out with such a device.
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Old 13th Mar 2014, 14:16
  #2746 (permalink)  
 
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Isca: are you serious that you had such a discussion with a pump jockey?

In my part of the world, which overlaps yours, I tell the guy how much fuel, and he pumps it. Period. He does not get a vote on how much fuel goes in, and I cannot fathom a scenario where you would have to explain yourself to a fuel dealer. Man up!

And if I decide last minute to add 20 tonnes of fuel, it goes on or I don't. Its really that simple.
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Old 13th Mar 2014, 14:18
  #2747 (permalink)  
 
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Fuel load

Quote from ISCA
As an aside to those speculating the aircraft could have been "secretly" fully fueled you obviously don't know much about refueling procedure.
Well it appears unfortunately you do not either.
Different Airlines bestow different levels of responsibility and authority in allowing their crews to upload whatever fuel they feel is justifiable.
Therefore, unless you know exactly what MH crew refuelling policy and procedures are, the view you are espousing carries no weight.

Their fuel load was I believe still an area of discussion.
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Old 13th Mar 2014, 14:20
  #2748 (permalink)  
 
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To be fair Dai, your sonobuoys in the central Atlantic were designed to hear a submarine a couple of hundred meters below, within a km or so, and not a pinger from 4km down.

Emeraude also has a much larger sound collecting area than those buoys.

You're absolutely right that listening for data recorder sounds in 100-foot deep water full of shrimps, raindrops and shipping, large and small, is not going to be easy.

In water as shallow as the South China Sea, towed arrays are also going to come into problems, as they are going to be in water whose depth is comparable to their length.

I would bet that a trawler has to be the most likely to find the wreckage.
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Old 13th Mar 2014, 14:24
  #2749 (permalink)  
 
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MAS confirmed in the Beijing press-con at 6pm just now that the signal of the ringing phone of a missing passenger is now traced to the US.
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Old 13th Mar 2014, 14:29
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Australopithecus
Isca: are you serious that you had such a discussion with a pump jockey?

In my part of the world, which overlaps yours, I tell the guy how much fuel, and he pumps it. Period. He does not get a vote on how much fuel goes in, and I cannot fathom a scenario where you would have to explain yourself to a fuel dealer. Man up!

And if I decide last minute to add 20 tonnes of fuel, it goes on or I don't. Its really that simple.
It depends if your airline has been paying the bills. I worked for one that did not! But then you're into different problems like repatriation and is the money in the bank on pay day?
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Old 13th Mar 2014, 14:31
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Sounds Detected

If the US or another country had a SOSUS (or similar) system near there, wouldn't it be possible to listen for an anomaly that could be the plane impacting the water. This would more or less confirm the plane crashed into the ocean.
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Old 13th Mar 2014, 14:33
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I am still amazed that no-one in authority appears to have mentioned checking seismic recording equipment. A couple of previous posters here have mentioned it.
Seismic equipment can throw up a record of the tiniest earth tremor - and 200+ tonnes of aircraft hitting land or water at 500, 600, or 800kmh must have produced a measurable shock wave (if it has crashed, as we must presume, is the more likely scenario).

Maybe the only way there would be little shock wave is if the aircraft stalled and flew into the water nearly level, a-la AF447, at just over 200kmh.
In which case, surely there would be a pile of floating debris? 10% of the B777 construction is composite, I've been informed, so would that style of composite float? Seating, bodies, carry-on luggage, a lot must float for days?
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Old 13th Mar 2014, 14:34
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Malaysia ask for radar data from some neighboring countries.


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Old 13th Mar 2014, 14:36
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@MartinM
This means that the Air Forces in the region are operating like Swiss Air Force these days. 8am in the morning to 6pm in the evening.
Minus 2 hours for lunch, of course . . . at least in the case of the Swiss ... but you know that already!

@Luke Sky Toddler
Still confusion about this so let's put it to bed, I was flying and on the same frequency at the time, Ho Chi Minh ATC started going mad trying to contact the MH370 on 121.5 at around 00.30 local Vietnam time. That is 01.30 Malaysia time, 1730 Z.
First-hand information - hallelujah! Many thanks

@Etudiant
Re the fuel load, it was stated very early in this event that the aircraft had 7 and a half hours of fuel loaded. So there was plenty of gas to go even further than the 4 hours post loss of contact.
No, it was stated that it most likely had around 7 and a half hours fuel - not the same thing at all!

Harping back to the point I made goodness knows how many pages ago, but last night my time, whilst I recognise the limitations of FR24 and the like, there are 3 transponder anomalies (as previously stated) that show up in the 90 minutes or so of interest and also in the local area.

They just happen to affect ONLY MAS370 and 2 of the aircraft nearest to it (though UA895 appears to be unaffected)

KAL672 as it passed 105.2 East at 16.55 UTC
CCA970 as it passed 105.25 East at 17.02 UTC
MAS370 as it passed 103.6 East at 17.21 UTC

This begs the question what else was in the area, perhaps travelling NW-ish at the time that had the capability to, and may have affected all 3 transponders AND ONLY THOSE THREE

Perhaps the illustrious Electronic Warfare ship that is now "assisting" with the search and whose Govt are not exactly fans of the Chinese (who themselves are in a very good position to sink the fiat dollar)?

Or should we only consider possibilities that point to Eastern and/or Muslim countries?

Perhaps nothing at all, perhaps not.
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Old 13th Mar 2014, 14:37
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Originally Posted by island_airphoto
Mode A/C only sends the numbers you set.
Mode S (and ADS-B) also has the airplane ID and AFAIK that is not readily changed in flight.

EDIT: maybe not. Apparently some CAN change the airplane ID from the cockpit.
Anyone know if the 777 can do this?
Of course you can change your aircraft ID (call sign) in the cockpit. The call sign is your flight number as in "MH 370". This changes for each flight and is not specific to any one aircraft.

I think this only applies to ADS B or CPDLC where the crew enters the flight number for the particular flight in the Flight Management Computer.

Non ADS B flights would have the Call Sign entered by ATC when they assign the transponder code for the flight.

(please correct me if this information is not correct)
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Old 13th Mar 2014, 14:40
  #2756 (permalink)  
 
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I'm a current B777 pilot.

About a year ago, in response to a Boeing Flight Crew Ops Manual Bulletin (BAB-95) relating to a potential software glitch affecting the selected altitude on the MCP, the operator I fly for changed our procedures to comply. Before the change we used to leave the Altitude increment selector in the 1000s position, subsequent to the change it is now routinely left in the Auto position (i.e 100 foot increments).

Had the flight crew experienced a rapid decompression then following donning of oxygen masks, establishing comms between the two of them, checking for cabin altitude/rate and passenger oxygen as required the next checklist item calls for an emergency descent. In my company this is routinely taught as a double loop starting with selecting a lower altitude on the MCP altitude selector, optionally using HDG/TRK SEL to turn off the airway, pressing the FL CH switch (commence descent at current IAS), deploying the speedbrake and ensuring the thrust levers are closed. Once the descent is established a second sweep tidies up the altitude selected (MSA/10k'), refines the heading, increases speed if appropriate and checks again for speedbrake deployment and thrust lever closure.

If there had been an explosive decompression centred on the E&E bay that knocked out all comms equipment and the crew oxygen could it be that the initial actions of the emergency descent checklist, the first sweep, be accomplished then hypoxia set in before the second sweep could be completed?

Under the old 1000s position of the ALT SEL an anticlockwise spin would reduce the selected altitude by many thousands of feet, an anticlockwise spin of the heading could give a large heading change to the west, the aircraft would descend at current IAS (normally in the cruise at FL350 M.84 equates to 250-260Kts indicated). However if the ALT SEL was in the Auto position a quick spin would change the selected altitude by only several hundreds of feet, possibly by pure chance FL295?

This scenario could explain the lack of comms, the primary radar target tracked on a westerly routing and the fact that no debris has yet been found. At FL295 the pilots would succumb quickly to the effects of hypoxia, the passengers likewise once the passenger oxygen was depleted. The cabin crew may have transferred to portable oxygen and attempted to reach the flight deck (my company trains the cabin crew to do exactly that if the descent has not commenced within 80 seconds). However even had the cabin crew entered the flight deck would (could?) they attempt a radio call, once they removed their mask there wouldn't be much time of useful consciousness to get that call out even assuming they knew how to.

If I had access to satellite imagery I think I might extend the search out in the last presumed direction of flight to the fuel exhaustion point and see if anything was there.

Possible? Plausible?
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Old 13th Mar 2014, 14:42
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I hope someone is doing a carefully controlled sonar survey of the area where contact was originally lost.
The problem is the sea between Thailand, Vietnam and Malaysia is like a puddle. It's extremely shallow, about 200 feet deep, and likely full of junk already. You can't easily use sonar. If no-one finds any debris soon, then the wreckage is probably going to be found accidentally in the end by being snagged by a fishing net.

It might also still have been moving fast enough on impact in shallow water that it embedded itself in the mud on the sea bed, muffling any pingers.

Without better inferred positions from radar and radio transmission records, the search for the wreckage may be a long one.
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Old 13th Mar 2014, 14:46
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ploughman,

How would the cabin crew get into the flight deck to bring the oxygen if the occupants were unconscious as their oxygen was out. Is there no backup oxygen carried in the cockpit in case a crew mask fails?

Surely the whole point of new locked doors is that you're not able to break in, and so someone would have to admit the cabin crew with their bottle. A flaw in this back up plan?
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Old 13th Mar 2014, 14:49
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You have to explain the total lack of any form of communication from the aircraft past the point of known contact.

Do these theories of total comms blackout but still flight capable aircraft hold any water.
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Old 13th Mar 2014, 14:49
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Or SOSUS reports

There is an extensive SOSUS sytem in that area that would have detected a noise of that magnitude,
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