Malaysian 777 missing in action

[Will]

One SATCOM, mostly Inmarsat and more and more Iridium, which are not reliable if you disturb the plane

What kind of plane disturbance makes the SATCOM unreliable? Are you talking about turbulence, or malfunctions?

[Jeroen Hoppenbrouwers]

Bank 10 degrees left and the satcom link goes SATVOICE LOST.

At the higher latitudes, the geostationary Inmarsat satellites become a very hard target to track. Iridium is easier but there you are faced with gaps in between satellites. Theoretically there will never be any spot on Earth without at least one Iridium satellite at 8.5 degrees or higher above the horizon, but coverage holes (dark zones) do occur, handover goofs do occur, and a thunderstorm on the horizon exactly where the satellite is will have you go blank.


Hoppie

[Will]

Incidentally, CNN is now reporting that the plane was flying on regular airways as it headed out over the Indian Ocean in the direction of the Andaman Islands. Apparently, what ever happened wasn't random or wantonly destructive. Someone had a plan.

[Jeroen Hoppenbrouwers]

Yup, waypoint names and everything.

During the press conference in the afternoon of Mar 14th 2014 Malaysia's Transport Minister provided more details about the primary radar observation stating, the target was first picked up at waypoint IGARI at FL350 (editorial note: waypoint IGARI nearly conincides with the last secondary radar position of MH-370) at 01:21L moving towards waypoint VAMPI, then waypoint GIVAL and finally turning northwest towards waypoint IGREX. The target was lost at FL295 after GIVAL at 02:15L.

Follow the link for graphical map.
http://avherald.com/h?article=4710c69b

[Will]

Of course, one primary target looks much like another. They could have been tracking a military plane. Have they calculated the speed of the target? Anything under M0.75 or over M.090 probably wasn't a 777.

[Jeroen Hoppenbrouwers]

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

[Michael]

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.

[Will]

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.

[farrokh747]

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.....

[Garry Richards]

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.

[Richard McDonald Woods]

Now it appears that the ACARS may have been disabled. So what does the aircraft now NOT broadcast?

[Jeroen Hoppenbrouwers]

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

[Richard McDonald Woods]

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?

[Will]

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]

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.

[Jeroen Hoppenbrouwers]

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

[Peter Lang]

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

[Jeroen Hoppenbrouwers]

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

[Peter Lang]

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

[John H Watson]

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?