Sampling of posts from pprune.org for today. Thread has grown to almost 400 pages as we speak. Lots of good posts debunking any other cause but deliberate action; also mentions the astronomical sacrifices both the Chinese and French have made in their deployment of so many satellites just to locate this plane. #7496 (permalink) freshgasflow @ wildgoose : altitude versus oxygen Yes the oxygen percentage will remain 21 % at whatever altitude. But is it the oxygen percentage or partial pressure that matters ? At higher altitude, the partial pressure drops . ( partial pressure of oxygen = % oxygen X barometric pressure ) ========================================================================== #7498 (permalink) phiggsbroadband If the initial radar returns can be trusted, the plane was piloted in two or three distinct changes of course. On to 270 degrees, at the loss of the transponder. (Maybe on to 240 degrees over the Andaman Sea.) Then on to 180 degrees about an hour after. So someone was still alive then. ========================================================================== #7510 (permalink) hamster3null Quote: Originally Posted by BWV 988 View Post Though we only have information about the last MH370 ping at 0:11 UTC, a massive search operation in the middle of a remote ocean would only be carried out if the (unknown) hourly pings made that area feasible. As the flight originated near the equator, a mirror track to the north would also correlate with the returns, then leading to a last ping area in northern China close to the Gobi desert. Bearings more to the west, however, would appear less likely, given ping data is coherent. Though the flight originated near the equator, last known contact was not on the equator, and you have to account for that when making a mirror track. They are working off the tracks that end up roughly at 40S and 83E to 87E, which would be 2700 NM from the satellite epicenter at heading 155 to 160. Last known position is at heading 78. That would put the symmetrical site at 2700 NM due north (heading 356 to 1) - near Aral Sea in Kazakhstan/Uzbekistan/Turkmenistan. In addition, current search is based on the premise that the debris drifted substantially to the southeast in two weeks since the crash. They are searching way outside the arcs by now. One of the reasons why Australians are looking in the exact spot where they are looking is simple. It does not make sense to look further southwest, because the aircraft barely had time or fuel to get to where they are looking as is. On the other hand, it does not make sense to look further northeast, because Australians have a powerful over-the-horizon radar system (Jindalee) with coverage that extends almost to 30S 90E, and, if MH370 had gone down further northeast, it probably would have been picked up. This leaves a pretty narrow area where they could be looking. ========================================================================== #7512 (permalink) Hogger60 Quote: Shortly after last radio contact with ATC the crew have taken limited, action. I believe the aircraft has been taken into manual control by the Captain and turned approx 90 degrees away from current fight route with the intent of an emergency descent. One of the pilots have recognised the need to sqwark 7700 but due to hypoxia inadvertently turned off the transponder. The effects of hypoxia have resulted in the crew not donning O2 and the aircraft altitude varying as a result of an attempted emergency descent until they became completely unconscious. Why manual control? Decompression protocol on 777 leaves autopilot on during descent. To tune the transponder to 7700 you never touch the on/off switch. By the way, the altitude warning horn is very loud and reminds you to put on your oxygen mask. It is the 1st step in the checklist and the pilots would not have not tried to turn away, descend or squawk 7700 without doing this. I know this happened in the Helios accident, but we learn from others mistakes, and they didnt have an EICAS to tell them what was happening. Your supposition totally depends on both pilots ignoring a blaring warning horn, EICAS messages, master caution warnings, and doing more than one thing against their training, in other words being a totally incompetent crew, which I do not think they were. My two cents. ========================================================================== #7513 (permalink) GlueBall zark7 . . . Quote: Based on the facts available through the media, a decompression event is the most plausible scenario. Whether or not this was a slow (10000 cabin alt warnings??) or rapid decompression is unclear. Are YOU a pilot? At FL350 you wouldnt be instantly blue in the face and pass out... Do you KNOW how long it takes to don a quick-donning oxygen mask? It takes me two (2) seconds to pull the mask out of the slot with one swoop of my left hand and plant it on my face. ========================================================================== #7519 (permalink) Alycidon Donning mask Glueball is quite correct, you can don the mask very quickly, there is no requirement to remove the headset as the quick don O2 mask is designed to go over the top of the headset and if fitted with integrated smoke goggles, is designed to fit over spectacles. Removing the headset is not a requirement and IMO is often taught incorrectly by some SFI/TRIs. The clue here is quick don. ========================================================================== #7522 (permalink) Pontius NavigatorTime of useful consciousness at 35,000ft is not in seconds. For a start you have a lung full of air, CO2 and water vapour and that will see you OK for quite a time. I cant remember off the top on my head but we used to fly with cabin altitude at 39,000ftand you could certainly drop your mask to blow your nose. The rule changed above 40k and you were down to seconds. IIRC it was something like 20-30 seconds at 45k and you had to initiate a 5k/m descent with a minute. Higher still with considerable overpressure (and you would have had a mask on) you had 30 seconds to initiate the descent. ========================================================================== #7524 (permalink) GlueBall Quick-donning mask https://youtube/watch?v=4HMiF5YlWyk&ap=%2526fmt%3D18&fs=1 ========================================================================== #7527 (permalink) flash8 Quote: The aircraft flew on in LNAV or HDG SEL and at the MCP/VNAV altitude. If in LNAV and passing over the last waypoint the mode changed to HDG HOLD A perfectly valid scenario, and one that puzzled me hasnt been elucidated upon more.. rather than all of this obtuse deliberate zig zag stuff. ========================================================================== #7533 (permalink) Pontius Navigator Posts: 10,310 100%, thank you for the table, I was working from very old memory Refuting seconds, as I was, I was meaning iro 5-15 rather than minutes, half to one Pontius Navigator is online now ========================================================================== #7537 (permalink) larryboy maxnightstop, crew would prioritise these warnings, the warnings themselves appear on screen, latest warning on top, in red. Cautions and advisories would be below, in amber, each indented one character to the right. ========================================================================== #7544 (permalink) Ian W Quote: Originally Posted by RTD1 View Post As of 1:07, that is absolutely correct. The next scheduled ACARS comm was not until 1:37. The problem seems to have happened between 1:19 and 1:22. Were nowhere near solving this thing, but the press release from last night does seem to rule out a couple of widely speculated possibilities. ACARS would not wait till the next scheduled transmission for an emergency status message like fire or depressurization. ========================================================================== #7545 (permalink) Eclectic This is costing the Chinese massively in Satellite resources. Photo reconnaissance satellites typically follow a polar orbit. This goes over both poles, whilst the earth rotates underneath, so they spend equal amounts of time in the northern and southern hemispheres. The timing of the orbits puts them over their targets early in the morning or late in the afternoon, in sun synchronous orbits, to get 3D perspective. To change orbit to look at a different target uses up manoeuvre fuel. They obviously only have a finite amount of this so using it is incredibly expensive in terms of the life of the satellite. They also use fuel to counter the effects of orbital decay. During the Falklands war the USA changed the orbit of a KH-11 (which cost well over a billion dollars, more than a Nimitz-class aircraft carrier) to provide the UK with intelligence. Casber Weinberger earned his knighthood. When the Chinese moved as many as 10 satellites to the Gulf of Thailand/South China Sea it must have cost them an utter fortune in using up the life of these assets. When they changed the orbits again to cover the southern Indian Ocean it cost them yet another utter fortune. They will now have a very big shortfall in their reconnaissance capabilities for a few years as they have to manufacture new resources. These satellites have many sensors, not just the visible spectrum. Use your imagination a bit and they will have tried it. KH-12s weigh about 20,000 kg, which is a huge amount of kit. And they are not the biggest. They produce immense amounts of data, far more than could possibly be analysed by humans. So the initial analysis is done by computers, unless they are examining a known target. All this means that they can look at a lot of the sea and can examine it in surprising detail. If you just think of what they have already found it is needle in a haystack stuff. ========================================================================== #7546 (permalink) Rightbase Ghost Plane @ Capt Kremin Is there any info on how disruptive wind be over that flight? Could a significantly different HDG end up there? Oops - edit region to flight. ========================================================================== #7547 (permalink) Capt Kremin Rightbase, I dont have the winds on the day but a southerly track in that area would generally be all crosswind, there for I have used TAS as GS. It is a guesstimate. Generally in the tropics you have easterlies becoming westerlies the further you go south. they wouldnt even out because the westerlies are generally stronger.. It makes the direct track = deliberate action case that much stronger. ========================================================================== #7549 (permalink) rh200 Quote: This is costing the Chinese massively in Satellite resources. Not only them, the BBc are reporting France is retasking one of theres to redo the area as well. That table showing all the resources that countrys are putting in should have a column for satellites. ========================================================================== #7550 (permalink) Blake777 Capt Kremin There have been a few posts on this thread that have been masterly in their insight. Yours is one of them. Thank you. ========================================================================== #7552 (permalink) RichardC10 If MH370 wreckage found in Southern Indian ocean..... @Capt Kremin Nice one, very informative. On the wind issue, a uniform wind over the track would be taken out in the fitting of the ping data, it is just a triangle of velocities. As you say, a changing wind would give more deviation from the tracks you show. ========================================================================== #7572 (permalink) Bobman84 Quote: Originally Posted by Coagie How do you know it didnt burn itself out before doing too much damage? The plane could have flown itself until its fuel was exhausted. Does not explain anything as a fire to destroy all communication etc would also render the planes hydraulic systems and electrics to fail too, making the plane unable to continue flying for long. Seriously, how can you believe such a theory when it turned around as we know, but not towards the airport? Compare that to other major fires where communication of the situation on board was relayed to ATC (SR111 & SA295). ========================================================================== #7576 (permalink) Uncle Fred Excellent work Capt Kremin. Very nice graphic. I think that many of us who fly the 777 for a living agree with you. The AP is going to follow a limited number of lateral inputs--LNAV, HDG HOLD, HDG SEL, TRK, or LOC. Plus, for LNAV we know that it is a three-step process of selecting the waypoint, executing it, and then selecting LNAV on the MCP. How many times have we had that drilled into us about Execute then LNAV? At the very least, the initial turn off course and the entering and/or selection of new waypoints reveals very deliberate actions--by whom I will leave open pending further discovery and investigation. I think however, that many posters have overlooked just how deliberate those actions need to be and that they were most likely not the result of a happenstance case of hypoxia or fire brigade duties...
Posted on: Sun, 23 Mar 2014 20:50:32 +0000
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