Malaysian Airlines MH370 contact lost

[jehrler]

GarageYears,

I believe that this particular T7 DID HAVE Satcom, just not the Satcom antenna per the recent Boeing AD. Not the same thing at all.

Could be but if so then, as hamster3null noted above, what is the

Boeing 777's satellite-communication link designed to automatically transmit the status of some onboard systems to the ground

??

Which systems would these have been since it seems that the RR one is not satellite based and earlier posts claimed neither was the ACARS?

If it did have such capability and these systems need to ping the satellites (even when not transmitting any data) ala a cell phone, then why has it taken this long for anyone to notice that these satellite signals lasted for 4 extra hours after the last communication?

[MG23]

Originally Posted by jehrler

If it did have such capability and these systems need to ping the satellites (even when not transmitting any data) ala a cell phone, then why has it taken this long for anyone to notice that these satellite signals lasted for 4 extra hours after the last communication?

I'm sure anyone who may have received a communication from the aircraft was checking their logs on Sunday, but any relevant information takes time to percolate through the investigation.

[Chronus]

Thanks Lonewolf 50. The reason why I posted this up was to show that the seasonal variation in the hydrodynamics of the region is such that by now the Malacca Straights would have revealed its dark secrets and that The Andeman Sea would have carried it well out into the Ocean.
But had I been a betting man I would put my money on the Indian Ocean.

[fox niner]

According to the RR engine ping communications, it stayed aloft for 4 hours. Not three, or five, but four. That is pretty exact information.
Actually, that is the most exact information I have seen for quite a while.

[Richard W]

Asylum Seekers and Stolen Passports

An Iranian seeking asylum in Western Europe needs a visa in order to get to Western Europe. He's unlikely to get it if the Entry Clearance Officer suspects he will ask for asylum.

[wiggy]

if we ASSUME for a moment that, for example, racks E1-E4 at the MEC have been destroyed by a catastrophic event, with several electrical and other key system failures you'd have to be able to maintain trim and make pitch adjustments in a severely compromised cabin in terms pressurization.

Yep, that's why I'm struggling with the "MEC damaged,selectively and the aircraft flew for hours" scenario....

In fact I'm not really buying any mechanical/technical scenario I've heard so far ..I'm at a complete loss.

[clayne]

Originally Posted by fox niner

According to the RR engine ping communications, it stayed aloft for 4 hours. Not three, or five, but four. That is pretty exact information.
Actually, that is the most exact information I have seen for quite a while.

How about the exact information that shows the original WSJ reporter correcting their statement that it wasn't actually data related to RR engine monitoring?

[jehrler]

MG23,

I'm sure anyone who may have received a communication from the aircraft was checking their logs on Sunday, but any relevant information takes time to percolate through the investigation.

I understand but what seems to make this a bit of a long time to search is that, as noted in earlier posts, these communication devices have the equivalent of a MAC or IMEI address allocated based on the airframe.

This would, I imagine, make searching the logs much quicker as there would be an identifiable characteristic to a ping.

I also wonder if one can use triangulation or simply dead reckoning from the satellite(s) contacted to get a feel for where the aircraft went.

[flash8]

Would it be possible to bring an "all frequencies" jamming device on board powerfull enough to jam GPS/SAT/GSM/transponder etc.?

Yes, a commercial fairly easily available (although likely some flags would be raised) wideband RF Jammer with the sort of power needed would fit into a smallish suitcase, size in most cases here is proportional to power output and frequency range required.

[MG23]

Originally Posted by jehrler

I understand but what seems to make this a bit of a long time to search is that, as noted in earlier posts, these communication devices have the equivalent of a MAC or IMEI address allocated based on the airframe.

It still has to be validated, then passed on through the correct channels. That takes time.

Imagine if someone spoofed a signal, the people receiving the signal didn't validate it, announced it immediately, and that drew the SAR effort a thousand miles away from the real site. Not a good idea.

[V-Jet]

Interesting thing with hypoxia, and in pass this on to all who haven't done a chamber run, YOU FEEL MUCH WORSE POST HYPOXIC WHEN YOU GO BACK ON OXYGEN!

Thanks VR, and IW. All these years and I never knew! I can certainly attest to feeling like absolute crap at 0300 body clock time. You will not be performing well. Well enough, usually. But could easily part explain 'dumb' decisions/recognition at the start of procedure and the comment above lack of comprehension/ability if you regained consciousness prior to any impact.

IF there are 200+ pax sitting in liferafts somewhere they will be dying horrible deaths. I know ELT's etc should be activated but if not heard the results would be horrific. I would hope for the big bang/impact theory.

Decades of EP's training simply said 'no matter where you are you will only be in a raft for at most 48 hours' and the joke that (Qantas) the worst place to be would probably be just off SYD where you would be unlikely to get the worlds attention and would have to rely on local fishermen to get home is plainly a nonsense with some aircraft configurations.

[brika]

A/C comms

MAS/Boeing/RR all deny any engine maintenance data transmitted after 1:07 am, ie 1 hour after TO.

However, it appears that the a/c's maintenance troubleshooting systems continued to ping about once an hour - picked up by satellites - prompting US to head to the Indian Ocean to a position calculated at 5 hours flying time (no public data as to how many pings were transmitted).

Boeing/RR decline to comment.

Clearly, not every piece of data or a/c communication capability is in the public domain - for very good reasons.

WASHINGTON/PARIS, March 13 (Reuters)

Given that pings were detected upto 5 hours later, and given that these pings have to go through the antenna, it appears that the hull breach at the antenna site could not have happened.

[mseyfang]

As the days wear on, the issue of any debris drift does indeed become more and more of a factor. No one knows where the plane is, so I'm just putting this out there as a go-to reference in case something eventually turns up:


Real-time Navy model website for sea-surface temperature and currents:
HYCOM 1/12 degree page

The Indonesian Flowthrough and Indian Ocean are the most relevant sectors. As a point of reference, 100 cm/s is equal to 1.9 knots, and 1 knot is 46 nm/day. Most values are well below this.

Chart for the point roughly halfway between the crash and now, as
a general reference since there is little day to day change:

Thanks for posting that. Most interesting. With respect to the part I bolded, I presume you meant to say 1.9 kts is 46 nm/day, correct?

[glitchy]

...why has it taken this long for anyone to notice that these satellite signals lasted for 4 extra hours after the last communication?

This is engine-status VHF ACARS we're talking about, right? Satellite monitoring of VHF traffic is well within the realm of the possible, but the job is finding the relevant ACARS blocks in what's likely a mountain of noisy signals intelligence data, not to mention getting it approved for release.

I'm not at all sure the overall scenario hangs together, but if you want to speculate about a functional airplane, a deliberate transponder shutdown, and a quick descent to below ground-based VHF and primary radar coverage, having a satellite notice the engines trying to phone home makes some sense, and would also explain why RR never knew about it.

[answer=42]

@jehrler and others

If I understand correctly, the

Boeing 777's satellite-communication link designed to automatically transmit the status of some onboard systems to the ground

, presumed to be Satcom, pinged satellites for a duration of four hours, without actually transmitting any data.

Question:
Can you think of a scenario in which this satellite-communications link is severely damaged enough so that it does not transmit data but is not so severely damaged that it cannot ping?
Question:
Can you think of a scenario that produces the above outcome that does not involve manual intervention to cease data transmission, while not fully disabling the satellite communications link?

[Uncle Fred]

Indeed Ian.

For those of us who had to undergo periodic refresher training in the chamber, we realize that even though we were "taken" to altitude that it was all rather quick. It would be interesting to have a flight surgeon weigh in on what the recover would be if you were already at an 8000' cabin altitude for time (starting at 1 hour or so), the onset was insidious, fatigue, age, etc.

I agree in the chamber the recovery was quick. I just wonder if it would be so in the jet when it all came as a surprise and you then had to regain SA in short order to fly the jet.

Either way, thinking is quickly compromised.

[PlatinumFlyer]

"According to the RR engine ping communications, it stayed aloft for 4 hours. Not three, or five, but four. That is pretty exact information.
Actually, that is the most exact information I have seen for quite a while. "

I was under the impression that the pings lasted 4 hours, but that they only occurred every 30 minutes, so that the elapsed time could have been up to 4 hours and 29 minutes.

[tvasquez]

I just now saw my bonehead error. 100 cm/s = 1.9 kt = 46 nm/day. Fixed it.

[Coagie]

Jehrler: "If it did have such capability and these systems need to ping the satellites (even when not transmitting any data) ala a cell phone, then why has it taken this long for anyone to notice that these satellite signals lasted for 4 extra hours after the last communication?"


Jehrler, Even if an aircraft is equipped with satcom equipment to relay ACARS, it's a common mistake to assume, that it's communicating directly with a satellite. Instead, it communicates with a ground station, that relays it up to a satellite. Many areas don't have a ground station near enough to the aircraft, to get a good enough signal. Although technology exists, where commercial passenger planes could communicate directly with satellites, there's a lag in implementation, because it has to be tested to make sure it doesn't cause unexpected problems with other systems on the plane. Then standards have to be agreed upon, so it's usually a long time, between the time a technology comes into existence, and it's implementation on an airliner. Even changing the type of coffee maker in an airliner's galley takes years!

[Stuff]

MAS/Boeing/RR all deny any engine maintenance data transmitted after 1:07 am, ie 1 hour after TO.

Strictly speaking MAS/Boeing/RR deny that any data was received after 1:07am.

How about the situation where the aircraft was transmitting the engine data but no ground-station was available to hear it however the US surveillance satellites heard the aircraft trying to establish a link? Neither party is lying but it leads to the apparent conflict where one says nothing was received and the other says they heard a 'ping'.