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Malaysian Airlines MH370 contact lost

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Malaysian Airlines MH370 contact lost

Old 9th Mar 2014, 14:26
  #861 (permalink)  
 
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The aircraft wouldn't have to lose very much height at that distance before it dropped below the radar horizon for a land based radar site at 200Nm out. Nevertheless, I'm confused - why can they not say 'it was travelling at [x] knots on vector [y] at rate of descent [z] before it vanished from our scopes'? That's what military radar installations are there for, surely?
My AAA Radar consist of two systems a active search radar which goes in flat terrain in a 360 degrees view from zero to 25nm. So i have a capability to detect any moving subject within this dome of 25nm around my radar. I have coupled to this a tracking radar which allows me to track a specific subject up to 25nm. This is a very powerful radar. I can track down a bike driving inside the 25nm dome, if i like to.

Every radar has a dome it can scan. But i bet none of the search radar installations is directly sitting at the coast of MY or VN. So 200nm could be just not enough.

I personally would not see any reason why a level change would make the aircraft disappear from radar screen.

I don't think an AWACS or Sentry was in the airspace. I don't see any US carrier activity in that area. This could have been an advantage
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Old 9th Mar 2014, 14:26
  #862 (permalink)  
3db
 
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Coagie,
The 40kHz is an electromagnetic wave. Humans (and dogs) can't hear electromagnetic waves directly. We (and dogs) hear sound pressure waves, which dogs can hear at 40kHz but us humans can't.
The electromagnet (radio) wave is made audible for us by electronics. That is why they listen for it with a radio receiver. 40kHz does travel through water, but not very well. However, it also depends on how sensitive your radio receiver is, as well as a host of other things.
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Old 9th Mar 2014, 14:26
  #863 (permalink)  
 
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This means that MH370 got either destroyed immediately, which on AF447 was not the case, or MH learned from AF447 incident and keeps the ACARS data for themselfs.
So a conspiracy theory is brewing If they had the data...Why would they not just send the search party to its last known position?

Maybe because it was shot down by the Americans and they have told the Malaysian Govt they have to come and cover up their actions?

We've had alien theories...why not this one
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Old 9th Mar 2014, 14:28
  #864 (permalink)  
 
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The issue of cameras being installed is indeed a very sensitive one. I personally as a pilot do not support this. Firstly, Airline management could potentially abuse this information. When you are employed as a Pilot and achieve an Airside pass you are supposed to be scrutinised with background checks etc. Most Airlines still utilise locked door procedures, so we should be entrusted to carry out our duties with trust and our protocols prevent unauthorised access.

The more serious point is " big brother" I a, don't want someone to watch me picking my nose! B, as many other pilots will relate to, when we are under line check feel more pressurised. The last thing I want is when dealing with a serious problem the thought that the safety department/management will be viewing my actions after the event, and with hindsight. This could become a distraction and affect flight safety.

There could of course be an honest broker hat holds recordings and deletes within a defined period... But the CVR/FDR/ACAR's when located always paint the true picture.
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Old 9th Mar 2014, 14:30
  #865 (permalink)  
 
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<<Nobody seems to have addressed the question of how did those with the stolen passports enter Malayasia – if in transit at KUL from Thailand, how come that Thai exit immigration did not pick up on the stolen passports? Thailand issues entry visas, which should have expired in both the stolen passports. If they were already in Malaysia, where are their photos and fingerprints that Malaysian Immigration take for all arrivals? >>
So naive, stamps are easy to counterfeit. Where the photos are, in Malaysia even if they are not willing to say.
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Old 9th Mar 2014, 14:31
  #866 (permalink)  
 
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If they had the data...Why would they not just send the search party to its last known position?
Didn't they do exactly this on AF447? Yes they did, but the debris was 100nm off that position due to the ocean current.

I wounder why no one till now has posted the ocean current depication by the time of the incident.
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Old 9th Mar 2014, 14:33
  #867 (permalink)  
 
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The stolen passport and shadowy pax theorists seem to forget that if a hijacker (or hijackers) just wanted to down an aircraft and go down with it, they wouldn't be bothering to indulge in stolen passport shenanigans. They'd use their own passports because they wouldn't care about being identified. A stolen passport is used to evade proper ID, and the aim is to live in a foreign destination where they can't be picked up easily.

The aircraft is reported to have suddenly dropped around 700' from cruise, then altered direction some serious amount, somewhere in the range of 180 deg - then it totally disappeared - and not a shred of wreckage has been found after approximately 48 hrs.
Vietnam has 17 aircraft and 35 ships in the search, there are 8 other nations involved, with around another 40 aircraft and about 45 ships.

I'm beginning to think this is a suicidal hijack - the hijacker/s overpowered the crew, grabbed the controls and aimed the aircraft straight down vertically. It speared in vertical and buried itself in the sea bed, leaving very little surface wreckage, and badly damaging the FDR and pinger.
The FDR is designed to withstand an impact equating to approximately 310mph, but a vertical high-speed dive into relatively shallow water would cause serious damage to it.

After the recent stabbing attack in China, it would appear Muslim Uighurs would have enough reason to destroy an aircraft containing a large number of ethnic Chinese - and they would be able to do this more easily from a largely Muslim, multi-ethnic country - where the authorities would not be on high alert for Uighur terrorism, as the Chinese currently are.
The Uighurs have been linked to Al-Qaeda by the Chinese, and the Uighur stabbing attack is not the first terrorism attack on Chinese by Uighurs.

Last edited by onetrack; 9th Mar 2014 at 14:58. Reason: update ..
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Old 9th Mar 2014, 14:37
  #868 (permalink)  
 
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"Coagie,
The 40kHz is an electromagnetic wave. Humans (and dogs) can't hear electromagnetic waves directly. We (and dogs) hear sound pressure waves, which dogs can hear at 40kHz but us humans can't.
The electromagnet (radio) wave is made audible for us by electronics. That is why they listen for it with a radio receiver. 40kHz does travel through water, but not very well. However, it also depends on how sensitive your radio receiver is, as well as a host of other things."


3db, You're dead wrong! It's a sound wave coming from the pinger. These "electromagnetic waves" you speak of, don't travel very well in water, so the pingers on the black boxes use sound waves, not radio ("electronmagnetic") waves. For instance, think of how far a whale can communicate with sound in the ocean. With a name like "3db" you should know better!!!
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Old 9th Mar 2014, 14:39
  #870 (permalink)  
 
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I don't think there are too many cellular towers in the middle of the ocean!
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Old 9th Mar 2014, 14:40
  #871 (permalink)  
 
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Object suspected of belonging to missing plane found Vietnam’s Civil Aviation Authority says a navy plane has found parts suspected of belonging to the Malaysian Airlines plane, Reuters reports.
Parts of tail and door? Keen for further information.
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Old 9th Mar 2014, 14:41
  #872 (permalink)  
 
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ACARS and MH ?

Know next to nothing on this stuff (tho hugely interested) but plenty about Malayisan Work practices. Seems to me that lack of ACARS is a key part of the mystery, is it possible/conceivable that MH have not been collecting/monitoring it properly and/or have lost it ? If that were the case and ACARS data was being transmitted, just not received, it would change the whole picture wouldn't it ? Might also explain the concern about not getting the whole story at the press events.
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Old 9th Mar 2014, 14:41
  #873 (permalink)  
 
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@Onetrack
Not necessarily. Because those involved mght have been on a watch list so that explains unsing fake travel documents.
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Old 9th Mar 2014, 14:42
  #874 (permalink)  
 
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BREAK-UP AT ALTITUDE vs INTACT ON IMPACT WITH THE SEA

Pure speculation here, but if the aircraft had broken up in-flight at its cruising altitude would not wreckage be spread over a very much larger area and consequently be more likely to be spotted quickly, compared to the concentrated wreckage field which would result if the aircraft had impacted the sea more-or-less intact?
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Old 9th Mar 2014, 14:46
  #875 (permalink)  
 
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Nevertheless, I'm confused - why can they not say...
Because they don't know. The issue of radar coverage is rather complex:

Civilian ATC is used to monitor and control civilian airspace. It uses two types of radars - Primary Surveillance Radar (PSR) and Secondary Surveillance Radar (SSR). The first is a physical 'echo' from any object within range (as already discussed, that is typically 60NM), the second is essentially a two-way radio communication between two computers using an interrogation - response protocol. Most of the world (except the deep ocean regions and some very remote land areas) are covered by SSR, but PSR is typically based at major airports to cover the surrounding airspace. The information from both sources are displayed on ATC radar screens, and in an area with dual coverage an aircraft with no transponder signal will show up as an unidentified blip on the screen. However in areas with only SSR, aircraft with no transponder signal will not show up.

When MH370 'disappeared from radar', the transponder signal was lost. But that does not immediately equate to anything happening with the aircraft, it just means that there is no transponder response. This is why Malaysian ATC tried for another hour to contact the aircraft, and only when it should have been visible to Vietnamese PSR did they raise the alarm that something was amiss.

Military radar in normal peacetime works the opposite way. Rather than controlling civilian airspace, it just monitors it, with a real-time data link to civilian ATC. On military monitors the known and identified targets are blanked out, so observers can focus on any unidentified targets. Thus military radar would not have monitored MH370, and if in the few seconds between loss of transponder signal and descent below observable height an unidentified blip would have appeared, that would have likely gone unnoticed. In all such cases it is a lengthy reconstruction process to retrieve the primary military radar data (which may first need to be 'weeded' to remove traces of any hush-hush activity), then match all targets with known and identified aircraft before anything may be said with any certainty.

I'm sure this is being done as we speculate in vain. In such cases the radar manufacturer may also be involved to attempt to amplify any possible weak signals that would have been filtered out as background noise by the processing software, but would still be recorded within the primary raw data. Naturally this takes time measurable in days or weeks, and is usually done as a part of an investigation process if no other sources are available to reconstruct the last moments of an aircraft.

Last edited by andrasz; 9th Mar 2014 at 15:03.
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Old 9th Mar 2014, 14:50
  #876 (permalink)  
 
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Pure speculation here, but if the aircraft had broken up in-flight at its cruising altitude would not wreckage be spread over a very much larger area and consequently be more likely to be spotted quickly, compared to the concentrated wreckage field which would result if the aircraft had impacted the sea more-or-less intact?
Yes, spread over larger - no, for spotted more quickly

If the debris is all together the visibility would by better from the air as it would be a large dark anomalie in water.

To find a single part, as large as a rubber boat, in an area as large as, flying at probably 7000 feet or higher, is almost impossible.

Apart from this, think on all the rubbish cargo ships tend to loose all over the place. This reminds me on a movie i was just watching, "all is lost" with Robert Redford. Unless you put a big light on, no one will find you.
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Old 9th Mar 2014, 14:53
  #877 (permalink)  
 
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acoustic locator beacon

These acoustic locator beacon is are not that powerful!

Detection range at 200ft water-deph is only around 3000 meters.

I am not a SAR Expert but i think these Locators are not intended to be received by airborn search-teams but rather by ships, divers or subs.

By law they need to be able to transmit for at least 30 days.....
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Old 9th Mar 2014, 14:55
  #878 (permalink)  
 
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Pinkman, the WSJ article links to the same photo of the 'window panel' that we have already seen, could be any piece of unrelated floating debris (eg. some large piece of Styrofoam packaging). Until it is retrieved and confirmed as an aircraft part, it's no new information.

A positive search result would likely reveal a debris field rather than isolated pieces, the sea had been calm over the past 2 days.

Also by now looking for any oil slick would be rather futile. While thicker than petrol, aviation kerosene is still rather volatile, a thin surface film of it would have evaporated by now with 30C+ daytime air temperatures.

Last edited by andrasz; 9th Mar 2014 at 15:06.
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Old 9th Mar 2014, 14:56
  #879 (permalink)  
 
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Primary Surveillance Radar (PSR) ... is a physical 'echo' from any object within range (as already discussed, that is typically 60NM)
@andrasz

What limits primary radar to a range of "typically 60NM"? I mean, the distance to the horizon at FL350 is over 200NM, so is the range typically limited by sensitivity, or noise and clutter at low angles of elevation?
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Old 9th Mar 2014, 14:58
  #880 (permalink)  
 
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Aircraft can drop passive sonobouys which will detect the locator beacon.


The P3 carries about 100 of them in rotary dispensers. They can be set for depth and 2, 4 and 8 hour endurance but, in this scenario where you are looking for a short range transmission, you would set them for the shortest life so as not to block up the transmission channels to the aircraft.


Also temperature, salinity and thermal profile of the water will greatly decrease or increase the distance at which an acoustic beacon can be detected, you just need to search both above and below the isothermal layer.


Hope that helps.
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