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.

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.

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?

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.

@jehrler and others

If I understand correctly, the
, 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?

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.

"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.

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

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!

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'.

How much crippled will a T7 be when dual AIMS Cabinet fail?

It will loose communication (ALL?), displays (ALL?), navigation (ALL?).....and more.

The best I could figure out, 777 has separate locations for SATCOM low-gain and high-gain antennas. MH370 did not have a high-gain antenna, which is why it was not subject to the "fuselage cracking" AD, but it could still have a low-gain antenna for the ultra-low-bandwidth Inmarsat Aero L protocol. It's totally possible that Inmarsat Aero L would involve exchanging periodic standby messages "in background", without anyone noticing. But this is all total speculation at this point and I can't find any concrete data on the exact hardware MH370 had onboard, or on the satellite protocol (that would most likely be proprietary anyway.)

The White House said the engines were still running four hours after contact was lost.

White House: Hunt for missing airliner may extend to Indian Ocean - The Washington Post

Coagie

Think you are wrong there. Full CPDLC coverage on the North Atlantic, most parts of which are well out of range of land based receivers. All done by satellite. Many carriers get re-dispatch messages etc out there

glitchy

This scenario is the one that would seem to make the most sense for why it his taken so long to discover any pings past the loss of the transponder.

Some things that I believe are "facts".

1) Engine/airframe data is sent via satellite, specifically the Iridium system
and 2) Iridium, being originally designed as a satellite "cell phone" system, would continually ping satellites, even if data wasn't being sent, or phone calls not made.

So even if Boeing, or the airline, or RR weren't getting data, that doesn't mean that the Iridium network doesn't have a good idea where the aircraft is, pretty much all the time. At least if the hardware was powered up. Even if they didn't have an active Iridium subscription, wouldn't the system keep track of the receiver, if only to be ready to give it a subscription code?

Cell phones ping towers almost constantly so as to maintain a connection in case a phone call is made. The system has to know what tower (or satellite) has the phone in view, so your phone can be made to ring within seconds of a phone call.

Lots of assumptions here, but some lights are coming on.

Plane Flew For 4 Hours
 

SaturnV

Based on the Wall St. Journal reporter's accounts, the pinging lasted for four hours, at 30 minute intervals. So there was power and a functioning communication link during that interval. Depending on whether the U.S. can triangulate the location of each ping, that would give an approximate a location at the time of the last ping. That leaves up to a 30 minute flying distance from the point of the last ping.
According to the Journal reporter's radio interview, he mentioned several times that U.S. officials haven't ruled out the plane landing, or crash-landing on land.


This is beginning to look like either a sudden depressurization related pilot incapacitation or pilot initiated deliberate destructive action.

Coagie,

If that is true that is very interesting as it means that calling these SATCOM is really a misnomer. It also makes me wonder why this would be a useful addition for ETOPS aircraft as they would seem to spend a fair amount of time over open and base station free areas?

I just assumed (yes, I know) that when someone discussed SATCOM they were discussing an iridium like service (with the attendant high high costs).

It is an entirely plausible scenario that US SIGINT satellites picked up ACARS data or any other electronic emission from the jet - and that they are only now working that out.
They can monitor signals as weak as a hand held walkie-talkie from orbit.

Una Due Tfc:
"Coagie

Think you are wrong there. Full CPDLC coverage on the North Atlantic, most parts of which are well out of range of land based receivers. All done by satellite. Many carriers get re-dispatch messages etc out there"


Una Due Tfc, I Hope you are right. I checked into it how airliners used satcom 4 years ago, so my info is dated. Wow, has it been 4 years? Time passes quickly as you get older. 4 years used to seem to me like centuries! Now, 4 years ago seems like last weekend!