jcxroberts
Posts: 97
Joined: Tue Mar 11, 2014 3:41 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 12:34 am

The pilot's odd double transmission (MH370 remaining in flight altitude 350) seems consistent with the onset of undiagnosed hypoxia as does his final transmission.
 
dtw2hyd
Posts: 7491
Joined: Wed Jan 09, 2013 12:11 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:02 am

Quoting BaconButty (Reply 14):
absolutely fascinating stuff. Makes Duncan Steels mob look a little silly.

We are at a stage Malaysia might as well put a spare T7 on a Chinese cargo ship and drop where they want. Until we see some physical evidence, every report should be filed under BS category. Doesn't matter how well it is presented.
 
User avatar
7BOEING7
Posts: 3039
Joined: Fri Oct 12, 2012 5:28 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:51 am

Quoting WarrenPlatts (Reply 46):
then it would stay on the same GC track for another 1200 nm after passing RUNUT;

if it's going POVUS to RUNUT, if you put in RUNUT/-1200 that would be the same point as POVUS. If RUNUT was the last waypoint you can't do an along track waypoint that is beyond RUNUT, you could do RUNUT/180/1000 after RUNUT which would take you to a point 1000nm south of RUNUT

Quoting WarrenPlatts (Reply 46):
Also, is there a limit to how far away a waypoint can be? E.g., could a pilot over the Indian Ocean select a waypoint in Argentina, for example?

No. In the Puget Sound area we used a waypoint TOU most of the time, which in our case stood for Tatoosh. Depending on the data base if we chose the wrong TOU we'd be on our way to Tolouse, in which case we'd get a message indicating we didn't have enough fuel.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:53 am

I have no idea why they decided to say it was probably a depressurization. There's really nothing to indicate that at all.

Now we have the media basically announcing that the cause of the incident has been found...

Strange.
 
sipadan
Posts: 322
Joined: Wed Mar 12, 2014 7:06 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 2:42 am

Quoting LTC8K6 (Reply 53):
I have no idea why they decided to say it was probably a depressurization. There's really nothing to indicate that at all.

Now we have the media basically announcing that the cause of the incident has been found...

Because to suggest an autopilot flight for well over 5 hours, AND to remain NEUTRAL, they had to at least imply an unresponsive crew. Had that implication NOT been made, then there is only one thing that could be inferred... an intentional act.

Hypoxia in merely a representation of one possible scenario that would allow for their autopilot theory to be possible.

Note well that they never mention the possibility of a 'lost' crew. Keep in mind that they also stated that the the a/c was functioning perfectly (thus their assumptions), aside from comms.

[Edited 2014-06-26 19:46:00]
 
WingedMigrator
Posts: 1771
Joined: Wed Oct 26, 2005 9:45 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 3:14 am

Quoting LTC8K6 (Reply 53):
I have no idea why they decided to say it was probably a depressurization.

I have no idea where you got this third-hand information. The report theorized hypoxia (which encompasses all possible root causes of an oxygen-poor environment, one of which is depressurization) for the sole purpose of defining an underwater search area.
 
sipadan
Posts: 322
Joined: Wed Mar 12, 2014 7:06 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 3:33 am

Quoting WingedMigrator (Reply 55):
I have no idea where you got this third-hand information. The report theorized hypoxia (which encompasses all possible root causes of an oxygen-poor environment, one of which is depressurization) for the sole purpose of defining an underwater search area.

I think his point was that in supplying for us a hypoxia scenario, they also are endorsing it (they say this bluntly, hence their assumptions). To an ill-informed media, this seems to suggest something 'accidental'.

Of course, they have a clear disclaimer stated, but this tends to escape the headline seekers.

It is interesting, however, that they give no mention to a scenario where a crew member CHOOSES to be unresponsive.

If you're going to float hypoxia, is it not also fair to float intentional, just to balanced? I suppose there were a great many legal considerations that precluded them from even mentioning this.
 
User avatar
Finn350
Posts: 1595
Joined: Tue Jul 09, 2013 4:57 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:12 am

Quoting dtw2hyd (Reply 51):
I have no idea why they decided to say it was probably a depressurization. There's really nothing to indicate that at all.
Quoting sipadan (Reply 54):
Because to suggest an autopilot flight for well over 5 hours, AND to remain NEUTRAL, they had to at least imply an unresponsive crew. Had that implication NOT been made, then there is only one thing that could be inferred... an intentional act.

It is very logical to think that everybody was incapacitated due to hypoxia. The depressurization can be either intentional or accidental, and they don't draw (and they don't have to draw) any conclusions on the cause of the depressurization.

Quoting tailskid (Reply 48):
This generates another line of position, that intersects the 7th arc only in two places.
Quoting tailskid (Reply 49):
My prediction would be to look at the point where the A/C would be expected to run out of fuel on a southbound great circle course from POVUS.

The performance bound boundaries define just the boundaries beyond which the plane cannot have flown. The intersection points don't have any special meaning as one doesn't know where the plane turned south.

[Edited 2014-06-26 22:25:16]
 
sipadan
Posts: 322
Joined: Wed Mar 12, 2014 7:06 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:51 am

Quoting Finn350 (Reply 57):
It is very logical to think that everybody was incapacitated due to hypoxia. The depressurization can be either intentional or accidental, and they don't draw (and they don't have to draw) any conclusions on the cause of the depressurization.

I agree that this is logical. However, IF you subscribe to an intentional act, as I do, it is also logical to believe that not everybody was incapacitated, or at least not at the same time.

In fact, it's quite illogical to believe that Zaharie himself was incapacitated at the beginning of that leg of the flight,

[Edited 2014-06-26 22:59:13]
 
User avatar
Finn350
Posts: 1595
Joined: Tue Jul 09, 2013 4:57 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 6:15 am

Quoting sipadan (Reply 58):
However, IF you subscribe to an intentional act, as I do, it is also logical to believe that not everybody was incapacitated, or at least not at the same time.

I fully agree on that. Even the report implies somebody most likely re-configured aircraft electric buses at 1825 Z (SATCOM device booting up), turned south a few minutes later and set up auto-pilot. After that the report assumes no further human intervention.
 
65mustang
Posts: 84
Joined: Wed Mar 19, 2014 1:28 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 6:57 am

Quoting sipadan (Reply 16):
If you can't see that the Malaysians are engaged in a campaign of deception and obfuscation, I really don't know what to tell you. Their behavior certainly suggests many possibilities. I suggest tilting your orientation to 'nefarious' and hypothesizing from that premise.

There is something nefarious going on.
 
User avatar
HAWK21M
Posts: 30050
Joined: Fri Jan 05, 2001 10:05 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 10:37 am

Someones hiding something..........a blunder by the military......a possibility.
I may not win often, but I damn well never lose!!! ;)
 
art
Posts: 3038
Joined: Tue Feb 08, 2005 11:46 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 10:53 am

MH370 inquiry puzzles over initial satcom message

http://www.flightglobal.com/news/art...ver-initial-satcom-message-400804/

Sorry if this gas already been covered in previous posts.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:00 pm

I thought the first handshake was always labeled as a "turn" because the turn was what supposedly generated the handshake?

It was even called a "sharp" turn because it caused the need for a handshake due to loss of the SAT com link during the turn?

What am I missing or mis-remembering?

Are they now saying the first handshake was due to a loss of power to the SAT com system on the plane?

[Edited 2014-06-27 06:03:12]
 
User avatar
Buyantukhaa
Posts: 2324
Joined: Thu May 13, 2004 5:33 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:09 pm

Quoting LTC8K6 (Reply 63):
I thought the first handshake was always labeled as a "turn" because the turn was what supposedly generated the handshake?

It was even called a "sharp" turn because it caused the need for a handshake due to loss of the SAT com link during the turn?

What am I missing or mis-remembering?

The sharp turn was thought to correspond with one point in the following diagram:



The turn did not trigger a handshake most likely. There is a mismatch between prediction and measurement there, and that is also the longest gap in communications between MH370 and the satellite. So something interesting must have happened there, but what?
I scratch my head, therefore I am.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:09 pm

Yes, the report says that #1 and #7 were initiated by the aircraft and that both were likely due to power loss.

"1st and 7th handshakes
The 1825 and 0019 SATCOM handshakes were log-on requests initiated by the aircraft. A log-on request in the middle of a flight is not common and can occur for only a few reasons. These include a power interruption to the aircraft satellite data unit (SDU), a software failure, loss of critical systems providing input to the SDU or a loss of the link due to aircraft attitude. An analysis was performed which determined that the characteristics and timing of the logon requests were best matched as resulting from power interruption to the SDU.
Approximately 90 seconds after the 1825 log-on request, communications from the IFE (In Flight Entertainment) system on the aircraft were recorded in the SATCOM log. Similar messages would be expected after the 00:19 logon request, however none were received. This could indicate a complete loss of generated electrical power shortly after the 7th handshake."
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:12 pm

Quoting BuyantUkhaa (Reply 64):
The turn did not trigger a handshake most likely.

Yeah, it seems odd to me now.

This is the first I have heard of the #1 handshake being initiated by the airplane.

I have followed this thing closely. Don't know how I missed that.

What happened at that time is a very good question.
 
Leeloo
Posts: 30
Joined: Fri Jan 22, 2010 7:43 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:20 pm

Hello all,

After reading a lot in the threads since the accident i need to submit a question or comment here.

Have the flight envelope been reconstructed according to known radar data and as per known satcom hand shake timings etc? I mean it should be possible to reconstruct the whole flight in real with a identical 777 to match the satcom data timings and so forth to get a pretty accurate point of crash. I'm an amature in the aviation world as you might understand but do have a lot of experience in the marine sector which has it similarities.

A real equipment reconstruction adjusted to match the known data would in my mind be the only way to get a clue of what has happened here. Has this been done!?

Kind Regards,
Fredrik Hageberg
Sweden
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:35 pm

Quoting leeloo (Reply 67):
I mean it should be possible to reconstruct the whole flight in real with a identical 777 to match the satcom data timings and so forth to get a pretty accurate point of crash.

That's not really possible if you think about it. We don't know the route the plane took very accurately, except for the first part, up to IGARI.

No one is going to risk actually flying a 777 into the SIO in the manner that 9M-MRO flew.

Besides, if they could reconstruct the flight well enough to fly the route with another 777, then they really wouldn't need to actually fly the route.

Inmarsat did use other planes and other flights to compare data.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:44 pm

Quote:
To experience a power interruption sufficiently long to generate a log on request, it was considered that a loss of both AC buses or, a disabling of the automatic switching, would be required.

So what caused that first log on request from the airplane?
 
Leeloo
Posts: 30
Joined: Fri Jan 22, 2010 7:43 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:51 pm

Quoting LTC8K6 (Reply 68):

Well, we do not know the path of the flight but we do know the data from the satcom etc. If several test and reconstruction flights were to be done (various altitudes, speeds etc) and adjusted to match (in real time) the data from MH370 i think there would be a better understanding of the flight envelope and eventually a more precise point of crash to be found. I don't see any safety issues with a reconstruction if it's done in a good way, in sections of the flight or similar to get the range needed.

With all due respect, computer simulations and calculations might be the way in todays investigations but if I was a part of the investigation team i would for sure ask Boeing/MH for an identical piece of equipment and start to reconstruct the envelope together with Inmarsat and their data.

Just wanted to make an input!

Thanks
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:56 pm

Quote:
The earlier SDU log on request at 18:25 UTC was also considered likely to have been due to a power interruption. As this power interruption was not due to engine-flame outs, it is possible that it was due to manual switching of the electrical system. Therefore it is possible that the aircraft’s electrical configuration was not in the normal state (i.e. the left IDG powering the left AC bus and the right IDG powering the right AC bus) at the time that the first engine flamed-out.

So how did that happen?

Was someone trying to make sure every comm possibility was powered down?
 
tailskid
Posts: 844
Joined: Fri Jun 06, 2014 7:27 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 1:58 pm

Quoting LTC8K6 (Reply 69):
So what caused that first log on request from the airplane?

The most logical and most accepted scenario is that the Left AC bus was intentionally isolated from it's power source (turned off); the sat transmitter & modem receive their power from the left bus (along with the IFE stuff.) De-powering this bus is something which can be done from the flight deck.

The 8:19 event is assumed to have been caused by a complete loss of power which brought down both AC buses.

Quoting LTC8K6 (Reply 71):
Was someone trying to make sure every comm possibility was powered down?

Yes, that's what it appears happened. De-powering he left bus would also shut down the flight management computer system for the left seat. It has been theorized that this might have been the main purpose for powering down the bus.

[Edited 2014-06-27 07:04:43]
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 2:01 pm

Quoting leeloo (Reply 70):
Just wanted to make an input!

You are far from the first person to suggest that strategy. It's been brought up many times.

If it were possible, or deemed a necessary risk, I'm sure it would have been attempted.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 2:04 pm

Quoting tailskid (Reply 72):
The most logical and most accepted scenario is that the Left AC bus was intentionally isolated from it's power source (turned off); the sat transmitter & modem receive their power from the left bus (along with the IFE stuff.) De-powering this bus is something which can be done from the flight deck.

The report clearly states that de-powering just one bus won't cause the SDU to lose power for long enough to generate a re-boot. So, shutting down the left bus will not generate a handshake.

You would have to shut down the bus, and disable the bus switchover system, or shut down both buses.

Only shutting down both buses will interrupt power long enough to trigger an SDU re-boot.

[Edited 2014-06-27 07:06:15]
 
tailskid
Posts: 844
Joined: Fri Jun 06, 2014 7:27 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 2:09 pm

Quoting LTC8K6 (Reply 74):
The report clearly states that de-powering just one bus won't cause the SDU to lose power for long enough to generate a re-boot. So, shutting down the left bus will not generate a handshake.

That's under a power failure scenario; in that case the left bus power is provided by the right engine's alternator.

However the left bus can be switched off manually, and in that case the right bus power is not used.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 2:33 pm

Quoting tailskid (Reply 75):
However the left bus can be switched off manually, and in that case the right bus power is not used.

I read that a little differently. You would have to disable the switchover system, and then switch off the left bus.
There could be situations where you might want to manually shut off the left bus and have the auto-switchover occur, yes?

At any rate, how is a hypoxic pilot managing to do all of this unintentionally?
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 2:38 pm

Quote:
After power became available, the SDU would take approximately 2 minutes and 40 seconds to reach the log on stage

So this puts our initial power interruption that far before the first handshake then?
 
User avatar
Buyantukhaa
Posts: 2324
Joined: Thu May 13, 2004 5:33 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 2:44 pm

Quoting LTC8K6 (Reply 77):
So this puts our initial power interruption that far before the first handshake then?

I'd say >2'40" before the final handshake (> because of the time to power up the APU or deploy the RAT) but in case of the first aircraft-initiated handshake, the power interruption may well have lasted more than an hour. The 2'40" refers to the time after the end of the interruption, not the beginning.
I scratch my head, therefore I am.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 2:56 pm

Quoting BuyantUkhaa (Reply 78):
in case of the first aircraft-initiated handshake, the power interruption may well have lasted more than an hour.


Yes, I should have said "at least", I guess.

The power could have been disabled near IGARI, I suppose.

If it was deliberate, that's probably the case.
 
WingedMigrator
Posts: 1771
Joined: Wed Oct 26, 2005 9:45 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 3:08 pm

Quoting LTC8K6 (Reply 76):
At any rate, how is a hypoxic pilot managing to do all of this unintentionally?

A useful analogy is that a hypoxic person behaves like a drunk person. Drunk people can perform complex tasks such as driving a motor vehicle, although they will perform them poorly and with errors.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 3:36 pm

Quoting WingedMigrator (Reply 80):

A useful analogy is that a hypoxic person behaves like a drunk person. Drunk people can perform complex tasks such as driving a motor vehicle, although they will perform them poorly and with errors.



Yes, hypoxia has been discussed a lot.

Who was still alive to power up the SDU at ~18:25 if the pilots were already hypoxic at IGARI?

[Edited 2014-06-27 08:36:59]
 
User avatar
7BOEING7
Posts: 3039
Joined: Fri Oct 12, 2012 5:28 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 3:53 pm

Quoting LTC8K6 (Reply 65):
Yes, the report says that #1 and #7 were initiated by the aircraft and that both were likely due to power loss.

Personally I'd go with the simpler approach -- both were due to an "airplane attitude" issue (a turn blanking the antenna).

"Approximately 90 seconds after the 1825 log-on request, communications from the IFE (In Flight Entertainment) system on the aircraft were recorded in the SATCOM log."

The fact that the IFE was still operational at 1825 would tend to rule out any of the previous "smoke" scenarios -- turning off the IFE is the fourth step in the checklist. The lack of any scenario that includes smoke also would tend to rule out the catastrophic failure of all the communications systems -- indicating the loss of TCAS was not accidental.

[Edited 2014-06-27 09:16:56]

[Edited 2014-06-27 09:17:34]

[Edited 2014-06-27 09:19:02]
 
bluesky9
Posts: 105
Joined: Sun Mar 23, 2014 1:26 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 4:34 pm

ATSB Report on Search
Excellent report, a breath of fresh air, outstanding clarity and thinking. Clearly leaving some options open, but working scientifically with what they have to refine the search area while keeping an open mind.

Hydrophones
Interesting commentary and analysis in the report (above) on the Curtin University hydrophone signals http://news.curtin.edu.au/media- releases/curtin-researchers-search-acoustic-evidence-mh370/. I was wondering whether it might be worth doing some blind calibration of the hydrophone sensors. For example by creating explosions with similar energy to an A/C impact in set locations and letting the Curtain University analyze them and see how close they get to the actual locations.

It is strange and interesting that according to the report that the Curtain has been refused access to the Chagos based hydrophone data. This makes this line of enquiry very interesting. In any investigation, when you encounter resistance push hard in that direction.

Hypoxia
I mentioned the hypoxia while ago, based on my experience of hypoxia and seeing others effected by hypoxia. The insidious nature of hypoxia is that most people don't recognize they are hypoxic and can appear relatively normal, but confidently make mistakes that make no sense to the non-hypoxic observer. For example adding two numbers, they confidently write down the wrong answer. It is possible they turned to the wrong frequency and then even forgot what they needed to do next. Someone mentioned that switching off the transponder was normal, for this part of the flight.

However as others have noted it is though hard to reconcile the hypoxia scenario with a large number of comms becoming inoperative at the same time, but I was wondering whether a lightning strike could take out a lot of these comms and the cabin altitude controls and warnings. I am fully aware that A/C are electrically bonded and designed to absorb lightning strikes without problems. I think I read somewhere that on average every A/C receives about one strike a year. A/C that I have piloted have experienced mid air lightning strikes, and generally you hardly notice it. However, lightning is unpredictable and can leap across internal airspaces, even when the expected path of least resistance would be through the bonded airframe. At least once after a lightning strike another crew member reported that the lightning jumped the airspace inside the A/C and showed me later the exit burn marks. I also have read reports of lightening jumping the air gap in inside boats, (which are also bonded) sometimes causing extensive damage to electrical equipment. Not sure what the weather was at the time, but could a lightning strike, have caused some of the electrical problems with the comms and pressurization and while the crew were distracted dealing these issues they became hypoxic (after about 15 to 20 seconds).

Suggestion:
12. If not already implemented maybe an independent cabin air pressure/altitude and warning light and alarm should be positioned in the pax cabin so that cabin crew are alerted immediately and independently if there is a problem with the cabin altitude.

Type of Impact
On the question of whether the A/C impacted the ocean at a high speed or in a controlled ditching. If a controlled ditching was achieved (hence no debris) why didn't the ELTs deploy as they are designed to? The fact they did not deploy points away from a controlled ditching. If the A/C impacted at high speed, there should have been debris with a fairly easily calculated drift distribution. However no debris was found, therefore the A/C either; i) did not break up on impact, or ii) is in a different location, or iii) there was debris but the big ocean effect resulted in it not being found. Most likely explanation is that it was a relatively high speed ditching and the debris was there (and may still be there) but was not found due to enormous size of search area.

Power Off 1st Handshake
Could the handshake be the result of someone (perhaps a pilot or someone with expertise) trying to achieve something in the electronics bay?

[Edited 2014-06-27 09:41:34]

[Edited 2014-06-27 09:45:50]
 
smallRED
Posts: 10
Joined: Mon Mar 31, 2014 3:16 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 4:37 pm

Hi hi,

Quoting BuyantUkhaa (Reply 20):
Source:ATSB

Thanks for the pic... even though seen many times, worth a re-look once in a while...


Got a query, if anyone can help explain....
The ping rings are mostly one hour apart, yet appear to be of different distances apart....does this mean
(a) speed is not constant, and in later hours, appear to speed up significantly? or
(b) if speed is constant, then direction is not constant, implying someone was navigating it till the end?

(i) if we assume both direction and speed is constant, then taking the distance from the 19:41 ring to the 20:41 ring, and from the 20:41 ring to the 21:41 ring, can we solve for direction and speed? (sorta like simultaneous equations?);
(ii) conversely, assuming constant speed, can we map the direction changes based on minimum speed between the 21:41 ring and the 22:41 ring? [perpendicular to tangent on 21:41 ring straight out to the 22:41 ring would be minimum distance covered in one hour, giving minimum speed?]

Anyone can help?
Thanks in advance..
 
 
tailskid
Posts: 844
Joined: Fri Jun 06, 2014 7:27 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 4:47 pm

Quoting LTC8K6 (Reply 76):
you would have to disable the switchover system, and then switch off the left bus.

There is no way to "disable the switchover system." But the left bus can be isolated from any power source. This might be necessary in the case of an electrical fire.

Quoting LTC8K6 (Reply 76):
There could be situations where you might want to manually shut off the left bus and have the auto-switchover occur, yes?
No

Quoting LTC8K6 (Reply 76):
At any rate, how is a hypoxic pilot managing to do all of this unintentionally?

IMO Zaharie did this intentionally.
 
User avatar
7BOEING7
Posts: 3039
Joined: Fri Oct 12, 2012 5:28 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 4:47 pm

Quoting bluesky9 (Reply 83):
Type of Impact
On the question of whether the A/C impacted the ocean at a high speed or in a controlled ditching. If a controlled ditching was achieved (hence no debris) why didn't the ELTs deploy as they are designed to? The fact they did not deploy points away from a controlled ditching

The ELT's are meant to deploy during a significant crash on land, a controlled ditching would not necessarily cause this and they are not designed to float. A high speed crash could have deployed them but they would probably have sunk with the airplane like AF.
 
User avatar
Finn350
Posts: 1595
Joined: Tue Jul 09, 2013 4:57 am

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 4:49 pm

Quoting 7BOEING7 (Reply 82):
Personally I'd go with the simpler approach -- both were due to an "airplane attitude" issue (a turn blanking the antenna).

The ATSB full report states (page 21) regarding both the 1825 Z and 0019 Z logon requests that "An analysis was performed which determined that the characteristics and timing of the logon requests were best matched as resulting from power interruption to the SDU."
 
bluesky9
Posts: 105
Joined: Sun Mar 23, 2014 1:26 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 4:52 pm

Quoting smallRED (Reply 84):
(b) if speed is constant, then direction is not constant, implying someone was navigating it till the end?


No the satellite is nominally stationary, so even a straight line will have this effect, once past the closest approach point or tangent.

Other factors that might alter the course, are the winds e.g. the effect of jet stream on the A/C, if say the A/P was in HDG mode. The jet stream goes from west to east down there, and get be over a 100kts. But it varies in width etc, so not sure if that would account for it. I think taken into account already by ATSB.

Another factor that could alter the course could be changes in magnetic variation maps and see how operating in magnetic HDG mode would effect the flight path. I think also taken account of by ATSB and others here.

Also in HDG mode rhumbline differs from great circle track.

[Edited 2014-06-27 10:22:52]
 
bluesky9
Posts: 105
Joined: Sun Mar 23, 2014 1:26 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:00 pm

Quoting Finn350 (Reply 87):
The ATSB full report states (page 21) regarding both the 1825 Z and 0019 Z logon requests that "An analysis was performed which determined that the characteristics and timing of the logon requests were best matched as resulting from power interruption to the SDU."

One comment on the interruption being caused by a turn, is that this conclusion was reached so early in the analysis, before other possibilities could be reasonably ruled out. This raises an amber flag for me. Why assume a turn, when there are other possibilities? Just something to keep in mind.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:06 pm

Quoting tailskid (Reply 85):

There is no way to "disable the switchover system." But the left bus can be isolated from any power source. This might be necessary in the case of an electrical fire.

So in the quote below, the report is talking about a failure of the switchover system then? Not someone turning it off?

Quote:
To experience a power interruption sufficiently long to generate a log on request, it was considered that a loss of both AC buses or, a disabling of the automatic switching, would be required.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:11 pm

What happens if you do a controlled ditching with the passengers and cabin crew still alive? Seems like that's very unlikely. There are several portable ELT's, plus the ELT's with the rafts. Someone is likely to deploy one of those.
 
Backseater
Posts: 478
Joined: Fri Aug 19, 2005 3:20 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:12 pm

It is definitely a challenging search problem. Even on land, T7s are sometimes hard to find!

http://i.imgur.com/tPsQZXk.jpg
 
tailskid
Posts: 844
Joined: Fri Jun 06, 2014 7:27 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:15 pm

Quoting LTC8K6 (Reply 90):
So in the quote below, the report is talking about a failure of the switchover system then? Not someone turning it off?

If both engines fail, the APU will provide power after it has started up. However it is not instantaneous as would be a switchover from left vs right alternators. It takes time to start up and stabilize itself. Then there may be other delays associated with a cold start of the modem. All in all they expect a 2:40 delay before a logon attempt after multiple engine failure and APU startup.
 
tailskid
Posts: 844
Joined: Fri Jun 06, 2014 7:27 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:17 pm

Quoting LTC8K6 (Reply 91):
What happens if you do a controlled ditching with the passengers and cabin crew still alive? Seems like that's very unlikely. There are several portable ELT's, plus the ELT's with the rafts. Someone is likely to deploy one of those.

Good point.
 
User avatar
7BOEING7
Posts: 3039
Joined: Fri Oct 12, 2012 5:28 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:34 pm

Quoting Finn350 (Reply 87):
Quoting 7BOEING7 (Reply 82):Personally I'd go with the simpler approach -- both were due to an "airplane attitude" issue (a turn blanking the antenna).
The ATSB full report states (page 21) regarding both the 1825 Z and 0019 Z logon requests that "An analysis was performed which determined that the characteristics and timing of the logon requests were best matched as resulting from power interruption to the SDU."

That's their best educated guess, I have mine -- time will tell.

Quoting tailskid (Reply 85):
Quoting LTC8K6 (Reply 76):you would have to disable the switchover system, and then switch off the left bus.
There is no way to "disable the switchover system." But the left bus can be isolated from any power source. This might be necessary in the case of an electrical fire.

By putting the left BUS TIE switch to Isolation and turning off the left GEN switch you depower the left AC bus. The only checklist these switches are used on relate to either recovering a bus failure or a generator failure -- they are not on any electrical fire checklist, there is none specifically.
 
LTC8K6
Posts: 1534
Joined: Fri Jun 05, 2009 8:36 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 5:46 pm

Quoting 7BOEING7 (Reply 95):
By putting the left BUS TIE switch to Isolation

Thanks. It would have been easier if they had written it that way in the report.  
 
User avatar
7BOEING7
Posts: 3039
Joined: Fri Oct 12, 2012 5:28 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 6:53 pm

Quoting LTC8K6 (Reply 91):
What happens if you do a controlled ditching with the passengers and cabin crew still alive? Seems like that's very unlikely. There are several portable ELT's, plus the ELT's with the rafts. Someone is likely to deploy one of those.

Mystery of MH370 wouldn't have been a mystery.

Quoting tailskid (Reply 93):
If both engines fail, the APU will provide power after it has started up. However it is not instantaneous as would be a switchover from left vs right alternators. It takes time to start up and stabilize itself. Then there may be other delays associated with a cold start of the modem. All in all they expect a 2:40 delay before a logon attempt after multiple engine failure and APU startup.

  
However, if multiple engine failure is caused by fuel starvation one wonders how much fuel would be available to run the APU and for how long?????

Quoting LTC8K6 (Reply 96):
Quoting 7BOEING7 (Reply 95):By putting the left BUS TIE switch to Isolation
Thanks. It would have been easier if they had written it that way in the report.

Then they would have had to explain WHY???? it was switched.
 
rwessel
Posts: 2448
Joined: Tue Jan 16, 2007 3:47 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 7:01 pm

Quoting smallRED (Reply 84):
Got a query, if anyone can help explain....
The ping rings are mostly one hour apart, yet appear to be of different distances apart....does this mean
(a) speed is not constant, and in later hours, appear to speed up significantly? or
(b) if speed is constant, then direction is not constant, implying someone was navigating it till the end?

If the aircraft was flying straight, and at a constant speed, but not flying directly towards or away from the satellite, you'd get different distances between the equal-time spaced rings.

That being said, you can use other knowledge to maybe construct possible courses.

It's actually pretty easy if direction and speed are constant. In that case, you know the aircraft has to be traveling in a direction where if crosses a pair of rings in the required time. If a pair of rings is 100mi apart, for example, and the aircraft is going straight at 500mph, it needs to be traveling at roughly a 12 degree angle relative to the (tangent of the) rings at the point where it crosses them. Of course that could still be on any point of the ring. Then you toss in a second pair of rings, with the same calculation, and find the points where a single straight, constant speed course allows both pairs of ring crossings.

If speed and direction vary, then it's much more difficult to come up with a precise path. For example, if two rings are very similar in diameter, it *could* mean that the aircraft was traveling nearly tangentially (parallel) to them. Or it could mean it was traveling perpendicular to them, but it went one way for half the time, turned 180 degrees, and flew back the other half of the time. Or it flew circles, or...

You can still factor other things in. For example, if you know a position, and then you have a ring crossing some time after that, it can only be on places on that ring that the aircraft could have flown to from the known position (IOW, if you the plane can't possibly have flown more than 600mph, and the ring crossing happened 40 minutes after the known position, you can rule out any points on the ring more than 400mi from the known position. For example, the 19:41 ping ring extends east well over Africa - we *know* that the aircraft wasn't on the eastern portion of that ring, since there's no way it could have covered that distance by that time. That then further also constrains the position of the next crossings, but fuzziness accumulates.

And factored into all this is that none of these things are known with precision, so there will definitely be error bars on any of these calculations. For example, just not knowing the altitude of the aircraft makes the rings about 20 miles "thick" horizontally. And any uncertainties in the time measurement (every microsecond of slop adds ~1000ft of uncertainty), or any uncertainties in the position or motion of the satellite, will add to it, etc.

Still, I think the working assumption is that a large segment of the flight *was* in roughly a straight line (and remember straight lines on globes are only occasionally straight lines on flat maps!) and at a constant speed, which is where the search areas are coming from.

[Edited 2014-06-27 12:14:53]
 
tailskid
Posts: 844
Joined: Fri Jun 06, 2014 7:27 pm

RE: Malaysia Airlines B772 Missing Enroute KUL-PEK Part 68

Fri Jun 27, 2014 7:22 pm

Quoting 7BOEING7 (Reply 97):
if multiple engine failure is caused by fuel starvation one wonders how much fuel would be available to run the APU and for how long?????

We can make a pretty good guess with the available data. It must have run for the predicted 2 minutes 40 seconds and then it got 9 seconds into the login before it died.

So it ran for about three minutes.

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos