Old 744 Forum

Archived posts

Malaysian 777 missing in action

Page: < 1 2 3 4 5 > »

Author Post
Moderator
Registered: May 2009
Posts: 2449
Location: KTMB
I presume the military know ten times more than what they release but for obvious reasons they keep their mouth shut. Tension in that area is always elevated.


Hoppie
Member
Registered: Jan 2011
Posts: 6
Jeroen Hoppenbrouwers wrote
I presume the military know ten times more than what they release


That's what I think. I still cannot believe that a ghost plane moves around over hours, crossing different ATC control zones and no one recognizes a inconsistency although the aircraft does not respond by radio.

Would the military of several countries accept that an unannounced aircraft travels in their airspace without taking any kind of action?

Something is going wrong here.
Member
Registered: May 2009
Posts: 958
Location: Chicago
The Americans are now announcing that the have "indications" that the plane crashed in the Indian Ocean. I wouldn't be surprised if that turns out to be correct. It's strange to think that it's not too late to give up hope about survivors.
_______________
Will /Chicago /USA
Member
Registered: May 2009
Posts: 503
Location: Mumbai, India
What would be the range of an average mil radar? 200NM? More? And below what ALT does it not work?

The action is shifting close to the Andaman Islands, part of India. The capital, Port Blair has a fair sized Indian Navy outpost -

As Michael says, how can an acft cross Thailand without being picked up by civil or mil radar....

And if she's travelled further east, on the route to IGREX, that would bring her under the Indian Navy radar....

Guess we're not being told everything.....
Member
Registered: May 2009
Posts: 418
Location: Australia
farrokh747 wrote
What would be the range of an average mil radar? 200NM? More? And below what ALT does it not work?

Australia's Jindalee long range radar, situated in the centre of the continent has a range of 3000 km and can see beyond Indonesia.
_______________
Garry

Website: flightsim.garryric.com
Member
Registered: May 2009
Posts: 309
Location: Winchester, UK
Now it appears that the ACARS may have been disabled. So what does the aircraft now NOT broadcast?
_______________
Cheers, Richard
Moderator
Registered: May 2009
Posts: 2449
Location: KTMB
ACARS carries all data messages, including maintenance reports and position reports (ADS-C).

The transponder carries not just radar returns, but also TCAS/ADS-B position broadcasts.

The only radios remaining when the data links have been disabled are voice VHF and HF, plus the ELT but that should not work unless you bang on it.

If Malaysian flies with an in-flight entertainment system that does live internet, there may be more stuff, but this is not very common yet and often uses ground stations only (phone poles aiming up).


Hoppie
Member
Registered: May 2009
Posts: 309
Location: Winchester, UK
My wife suggests that mobile phone signals should also have left a trace of the aircraft track. But we have heard nothing about this, have we?
_______________
Cheers, Richard
Member
Registered: May 2009
Posts: 958
Location: Chicago
Hoppie, there are conflicting reports going on. I'm hearing (1) that ACARS was turned off, and (2) the engines kept "pinging" satellites every half-hour for several hours. Can both of those be true at the same time? Can the engines somehow ping or transmit independently of ACARS?
_______________
Will /Chicago /USA
Member
Registered: May 2009
Posts: 958
Location: Chicago
Richard McDonald Woods wrote
My wife suggests that mobile phone signals should also have left a trace of the aircraft track. But we have heard nothing about this, have we?


I don't think this is likely. Cell phones don't work over very long distances. At altitude, the plane is too high for the phones to make contact with ground-based cell phone towers (not that I've personally tried that or anything, wink wink). Over the ocean the problem is obviously much worse.
_______________
Will /Chicago /USA
Moderator
Registered: May 2009
Posts: 2449
Location: KTMB
It is not impossible but I don't think that engines have independent antennas and other equipment that can reach out to satellites in orbit. But it isn't impossible, Iridium antennas are about the size of a toe slipper/flip-flop. You can stick one of these on an engine nacelle and the associated electronics are about the size of a pack of cigarettes.

Mobile phones have trouble reaching poles when you travel fast enough and high enough. At low altitude (3000 ft) it may work but even then I doubt a reliable connection can be established, including identifying the phone IMEI.

Plus, it's all classified and sensitive data. The authorities admitted already they simply don't disclose stuff they already know for sure.


Hoppie
Member
Registered: May 2009
Posts: 269
Location: between EDDF and EDDN
Richard McDonald Woods wrote
My wife suggests that mobile phone signals should also have left a trace of the aircraft track. But we have heard nothing about this, have we?



In an aircraft, the cell phones should be switched in flight mode. When you call one of them, there is no ring tone, but only the message, that "the person you have called, is temporary not available". I do not know if tracking in this status is possible and I'm also not sure if the airlines allow to leave the cell phones in online mode.

Here in Germany I have heard, that it is possible to track a cell phone even if it is switched off. The only way to be complete "invisible" is to remove the accu.
I also sometimes heard, that people or criminals have been found via cell phone tracking.

So when they say that the cell phones kept ringing (even if nobody was answering), they should know where the phones are. And in this case these phones should be in the area of a cell tower.

Peter
Moderator
Registered: May 2009
Posts: 2449
Location: KTMB
60-70% of passengers seems to fail to really switch their phones off properly. They may think they did, but didn't. So I think it is a myth that aircraft fly around with no phones on, blasting at maximum power in a vain attempt to reach a pole.

Nobody heard phones ringing. They heard the network ringing. That is something totally different. The network may or may not do this depending on loads of factors, excluding whether the phone is online or not.

Concerning tracking: many phones have a few cell modems plus WiFi plus Bluetooth and possibly even more. All of these can give away your position, and not all of these are switched off by Air Mode.


Hoppie
Member
Registered: May 2009
Posts: 269
Location: between EDDF and EDDN
Of course nobody knows if the cell phone owners heard anything.

What I understood from the news is that some relatives called the cell phone owners and heard what they normally hear when the line is not busy and the phone is online. Perhaps this behavior is different in other countries or with other operators.

From my own experience:
About 2 or 3 weeks ago, we had a cell tower failure in our vicinity. Some friends who wanted to call me stated, my cell phone told them, I would have been offline. They did not hear a ringtone, there was immediately the o.m. message. My cell phone was in online mode but for them I was "not available"

--
When not all possibilities are switched off even in flight mode, then they should find them, as long as the battery supplies power.

Peter
Member
Registered: May 2010
Posts: 843
I'm wondering how the ACARS was turned off (if it was). It's hearsay, but someone on PPRuNe was saying that the B777 ACARS circuit breakers are in the Main Equipment Centre (MEC).

Our B744's have Quick Access Recorders (similar to the Digital Flight Recorder, but with no crash protection). Our QARs record specific airplane data and send it to our maintenance centre at certain times. The QARs have their own antennae. I believe they are UHF, but not linked to satellites. Perhaps MAS has something similar for engine data?
Member
Registered: Jan 2011
Posts: 6
Several times I heard from people who had forgot to switch off their mobiles during flight. Arriving at the destination, they found welcome-SMS of all overflown countries. In theory it is always said that this should not work because of the high cruising altitude. In practice, lot's of people tell exactly this story. Nevertheless I also think that, dialing a victims cell phone number, it only responses the network, not the mobile.

Moments before AF447 plunged into the sea, not less than 24 ACARS messages were sent by the Airbus A330-200. Regarding MH370 we were told that there were only a few pings. Would a B772 not sent messages when alt decreases rapidly or engines stop working due to fuel shortage?

At the moment I think of a confused hijacker who does not really know what he wants, issuing conflicting demands several times. Or a kidnapper group facing problems to carry out their plan or in dispute with each other, flying around "helplessly". Fuel comes to an end, finally. In both cases an aircraft specialist must be involved.
Member
Registered: May 2009
Posts: 944
I assume that the NSA and its affiliated agencies have easy access to many more data and other transmissions than the civilian world knows about. But they will probably never admit to this, much like the other military organizations.

It's too bad they can't somehow release at least some of their information in case of emergencies...
_______________
Best wishes,

Phil Bunch
Member
Registered: May 2009
Posts: 944
_______________
Best wishes,

Phil Bunch
« Last edit by Phil Bunch on Mon, 17 Mar 2014 00:14:43 +0000. »
Member
Registered: May 2009
Posts: 958
Location: Chicago
Interesting article based on a statement from the Malaysian Prime Minister, quoting FAA and NTSB sources, saying the plane could be in central Asia. Look carefully at the map in the article. The last satellite data puts MH370 either in the ocean or else over central Asia, which includes western China, homeland of the Chinese separatist Uyghur movement.

http://www.slate.com/blogs/future_tense/2014/03/15/flight_370_disappearance_missing_airliner_apparently_flew_to_central_asia.html
_______________
Will /Chicago /USA
Member
Registered: May 2009
Posts: 497
Jeroen Hoppenbrouwers wrote
Concerning tracking: many phones have a few cell modems plus WiFi plus Bluetooth and possibly even more. All of these can give away your position, and not all of these are switched off by Air Mode.


Not switched off by air mode? Would that not defeat the purpose of having an air or airplane mode in the first place?

Jeroen
Member
Registered: May 2009
Posts: 497
Couple of things on the various mobile phone myths surrounding this tragic incident.

As pointed out earlier, the fact that you hear a ring tone, doesn't necessarily mean the mobile phone on the other end is ringing. It could be just the network. People still sort of think as a mobile call is a sort of one to one connection. It is, of course, but through a complex maze of routers, switches, fiber, microwave connections and various other radio frequencies. It all zero's and one's.

It is technically feasible or possible to be in range of a mobile network at say 35.000 feet. It is just not very likely. Mobile Network Operators want to provide radio coverage on the ground, not in the air. So typically your antenna's are pointing downwards. By the way, just because you see the antenna's mounted on the towers vertical doesn't mean they radiated evenly along a horizontal axes. We use electronic tilt. Radiowaves being radio waves and propagation will mean you get coverage in various spots, including at 35000 feet. A lot will depend on the technology and the frequency used. The higher the frequency (e.g. 1800-2300 band) the less coverage you get. 800-900Mhz will reach much further. And the old 450Mhz systems such as NMT450 had an incredible range.

When I was based in the USA and piloting my own planes, such as Cessna, Cirrus, Diamond I did some testing. I think I wrote about it on this forum as well. Cant remember the exact numbers anymore. But in general you would not get voice or data coverage above 10-12000 feet. That doesn't mean it can't happen.

Mobile network are planned so that coverage is provided through contagious "cells". Once your mobile phone is properly identified in the mobile network the network knows in which cell you reside. It will also know which are the neighboring cells. As you move toward the edges of your cell, radio coverage will weaken and the system will decide to hand you over to the next cell. This all happens without us users knowing, its a seamless handover, providing the system is well optimized.

These cells are planned out on the ground, based on frequency planning, power output etc. Obviously, some of that radio energy will make it all the way up to 35.000 feet. However, at that altitude the same cells might not be present, so the system doesn't know to which cell you need be handed over. In such a case you would experience a dropped call and or data session. As long as you have coverage, you will be able to call again, but you are unlikely to experience smooth seamless handovers at those altitudes.

Depending on country, technology, competition and sometimes legislation, operators will or will not allow you to roam between them. So there might be a network and your phone will actually pick up its signal, but it is not allowed to attach/register itself. If that happens during a call or data session, again the call will drop. Cross country roaming is mostly not allowed and also has some legal challenges.

So, if a mobile phone is switched on and registered in a particular mobile network, it is known in which cell the phone is located. And of course, the operator will know where that cell is, geographically speaking. Depends a bit, but a cell could be several square kilometers or even larger to something only say 100 square meters.

Within most mobile networks there are technical possibilites to narrow down the location even further. Either through what is essentially triangulation or by the help of built in GPS in your (smart) phone. In some countries it is legal requirement for the mobile operator to provide precise location information with any call to emergency services (e.g. 911). So they immediately know your location.

All of the above is based on a known mobile in a known mobile network. Once you know the number you can start looking for it. If you don't know the number or you don't know the mobile network it becomes very tricky, proverbial needle in the haystack type of scenario.

The idea that you can simply trace a mobile phone that is switched on is therefor in practice a little bit more complex. Lots of articles these days on NSA capabilities. I have no idea of their capabilities other than what I can make up from the various news articles. As they tend to be written by journalists rather than Telecom and or ICT specialist I'm not so sure what they can or can't. But it seems they listen in to calls rather then actually physically locate a phone. Two very different things.

There is this persistent believe that mobile phones can be traced, even when switched off. In order for that to happen we need something akin to a Men on the moon conspiracy to make that happen. There are literally thousand of engineers involved in the specification, standardization and design of Mobile telephony systems.

What is true is that when you switch of your phone, the location where you switched off is likely to be known. You move away from that position with your phone switched off, nobody is going to be the wiser!

Jeroen
Member
Registered: May 2009
Posts: 309
Location: Winchester, UK
Jeroen,
A most interesting post. Ta.
_______________
Cheers, Richard
Member
Registered: Jul 2009
Posts: 7
Interesting report that one of the pilots had a flight simulator in their home. I wonder what the details are?
Member
Registered: Jan 2011
Posts: 6
farrokh747 posted this on Monday 5th, 2014:

http://www.sharelor.net/1/post/2014/03/tribute-who-exactly-is-malaysia-airlines-captain-zaharie-shah-of-mh370.html
Member
Registered: Jul 2009
Posts: 7
Interesting link. He sounds very normal. Truly a mystery what happened up there.

Page: < 1 2 3 4 5 > »

Old 744 Forum is powered by UseBB 1 Forum Software