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Malaysia Airlines Loses Contact With 777 en Route to Beijing

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  • Originally posted by ptwtanks View Post
    Pilots flying unpressurized aircraft are required to use an oxygen supply above FL140. If the plane was at any altitude above FL140 and assuming it was slowly depressurized by the pilot, unconsciousness would ensue...
    Actually, healthy pilots would probably stay awake all day at 15,000 feet and operate the aircraft fairly OK.

    HOWEVER, it's almost like being drunk and human performance is somewhat degraded...

    And the time at 14 K is limited to only one or two hours... I think it's 12K or 10K for extended flight...time to check the FAR's...

    I'm thinking it's at ~20K where folks actually tend to pass out.

    And- as many have said- these are rough estimates, affected by a lot of factors- and hopefully containing a little safety margin most of the time.
    Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

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    • Originally posted by AVION1 View Post
      Fox Radio just played the recording of the "ping" signals detected by an australian ship. They sound identical to the ULB signals to me.
      Do you have a link?
      Hard that anybody heard it since at 37.5 kHz it is beyond the range of audible frequencies (it's ultrasound).

      But there are technologies that "shift" the frequency captured by the mic to make it audible.

      --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
      --- Defend what you say with arguments, not by imposing your credentials ---

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      • Originally posted by 3WE View Post
        Actually, healthy pilots would probably stay awake all day at 15,000 feet and operate the aircraft fairly OK.

        HOWEVER, it's almost like being drunk and human performance is somewhat degraded...

        And the time at 14 K is limited to only one or two hours... I think it's 12K or 10K for extended flight...time to check the FAR's...

        I'm thinking it's at ~20K where folks actually tend to pass out.

        And- as many have said- these are rough estimates, affected by a lot of factors- and hopefully containing a little safety margin most of the time.
        At 25000ft the time of USEFUL consciousness (TUC) is 3 to 6 minutes on average, what doesn't mean that a person can't remain with "colorful" consciousness for a lot longer.

        There are lots of shades between "usefully conscious" and "passed out".

        Example of persons that are conscious but not "usefully" conscious:

        This is an altitude chamber set for 25000ft


        This is a real hypoxia emergency above 26000ft (since at a point they are cleared down to FL260). It seems that the part where they descend to 11000ft is missing, but what a difference after they descend!

        --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
        --- Defend what you say with arguments, not by imposing your credentials ---

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        • Some of us in our younger days could live packing and climbing for weeks above 12k to 14k though it takes a week to get used to it. Everest was first scaled without oxygen and great exertion to 29k. If a pilot acclimatized at altitude (someone who lives and flies out of Eagle, they are the extremes.

          Now lets look at the smokers, much more dominant in the third world.
          Live, from a grassy knoll somewhere near you.

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          • Originally posted by Crow View Post
            Why do people consistently keep giving credence to this absurd notion that MH370 ascended to FL450 or above for a given length of time? That is simply not possible.
            I don't think 'consistently' is fair. I'd be very surprised to learn that a loaded 777 could attain 45,000 and even then I expect it would have to step climb there after considerable fuel burn. But then again I didn't think a 777 could simply disappear into thin air for six hours or move around under water flummoxing the ping detectors. We are learning all about the magical powers of the 777 in this episode.

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            • Originally posted by Evan View Post
              I don't think 'consistently' is fair. I'd be very surprised to learn that a loaded 777 could attain 45,000 and even then I expect it would have to step climb there after considerable fuel burn. But then again I didn't think a 777 could simply disappear into thin air for six hours or move around under water flummoxing the ping detectors. We are learning all about the magical powers of the 777 in this episode.
              My apologies Evan, I was referring in the main to the broad speculation beyond this forum, which as I said as a reliable source, I find the latter generally a delight to read.

              Kris, with respect, there is no such thing as an 'Everest Climber'. True the likes of Reinhold Messner were a 'different breed (in a metaphorical sense), although you could argue that Tibetian Sherpa's or the Quechuans of the Andes have adapted through an evolutionary process. Although research is still inconclusive they are believed to possess enhanced lung/respiratory capacity, higher levels of nitric oxide for greater blood circulation, a lower haemoglobin count and greater diffusing capacities than lowlanders. In spite of this - prolonged exposure way into the death zone and it all counts for s**t.

              Messner's solo ascent of Everest without oxygen required appreciable acclimation - you don't just bundle him in a depressurised aircraft and expect him to survive at 33,000 feet simply because of his pedigree as an 'Everest climber'.

              Evan, to me the 'magical' property of a 777 is its remarkable and impeccable safety record.
              As the Crow flies

              "Buy the ticket, take the ride"

              Comment


              • cnn reporting that they've once again picked up signals believed to be the ULB's.

                what boggles my mind is that devices designed specifically TO BE FOUND are so difficult to find. almost like the manufacturers made a half-hearted attempt at assuring they would be found. seriously, we have technology that can pick up things that are designed not to be found from over 10,000 yards away but these ULB's have a designed detectability of only a few kms at best?

                remember the BEA report from AF447 specifically recommended that the technology be improved/changed. obviously the rest of the world thought that was a bad idea.

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                • And yet, lowlanders stowaways have survived many-hours-long transatlantic jet flights at jet cruising altitudes and survived (barely).

                  I don't mean anything in particular. They were the rare exception, not the norm.
                  But as 3WE uses to say, almost every absolute statement is almost always wrong.

                  --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                  --- Defend what you say with arguments, not by imposing your credentials ---

                  Comment


                  • Originally posted by Gabriel View Post
                    And yet, lowlanders stowaways have survived many-hours-long transatlantic jet flights at jet cruising altitudes and survived (barely).

                    I don't mean anything in particular. They were the rare exception, not the norm.
                    But as 3WE uses to say, almost every absolute statement is almost always wrong.
                    Supposedly miracles have happened. I recall recently the case of a Romanian who survived a flight from Central Europe to Heathrow (I think from memory it was Munich). I don't think it went higher than FL260 - but that should have killed him. Also a Tahitian who similarly stowed away in the undercarriage and managed to survive the flight to the U.S.A. - subsequently moving his entire family there. If you don't get crushed by the landing gear, fall out upon deployment or freeze to death your chances are otherwise negligible.

                    Incredible what drives people to take such risks and the mental and physical fortitude and endurance in the face of adversity that a human being can sometimes summon. Astoundingly some are suggesting that there may even be those that are desperate enough to consider purchasing a Ryan Air long haul ticket when the service becomes available.
                    As the Crow flies

                    "Buy the ticket, take the ride"

                    Comment


                    • Originally posted by Crow View Post
                      Supposedly miracles have happened. I recall recently the case of a Romanian who survived a flight from Central Europe to Heathrow (I think from memory it was Munich). I don't think it went higher than FL260 - but that should have killed him. Also a Tahitian who similarly stowed away in the undercarriage and managed to survive the flight to the U.S.A. - subsequently moving his entire family there. If you don't get crushed by the landing gear, fall out upon deployment or freeze to death your chances are otherwise negligible.

                      You are joking right?

                      Comment


                      • Originally posted by BoeingBobby View Post
                        You are joking right?
                        You are a 'real pilot' right?
                        As the Crow flies

                        "Buy the ticket, take the ride"

                        Comment


                        • Hillary, Shipton and the Sherpas were at altitude without oxygen for some time so do some homework Crow.

                          Also, many stress and even die in the base camps or on the way up so anything can happen. Possibly what caused Shipton to fall on the way down.
                          Live, from a grassy knoll somewhere near you.

                          Comment


                          • Originally posted by Crow View Post
                            Evan, to me the 'magical' property of a 777 is its remarkable and impeccable safety record.
                            Remarkable, yes, in the right hands. But impeccable safety reocrd? Impeccable aircraft don't refuse requests for power on final and impact short of the runway or make wild uncommanded flight level excursions due to a glitch in the ADIRU. I realize these things have since been addressed and I consider it a remarkably safe aircraft but let's not kid ourselves about it having an impeccable safety record.

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                            • Why don't we train some dolphins for this kind of task? to find aircraft "pings" from the black boxes deep in the water?
                              A Former Airdisaster.Com Forum (senior member)....

                              Comment


                              • Originally posted by guamainiac View Post
                                Hillary, Shipton and the Sherpas were at altitude without oxygen for some time so do some homework Crow.

                                Also, many stress and even die in the base camps or on the way up so anything can happen. Possibly what caused Shipton to fall on the way down.
                                Not without substantial acclimatisation they weren't.

                                Thank you for your reply, but..."for some time"..."at altitude" be more specific. Not sure what point you're making. I'm referring to ascent beyond the death zone. Perhaps set some homework yourself.

                                Genuinely, I do have homework to do now and it's dreadfully dull - but thanks for the suggestion. I would love to find the time to delve into my copy of Nanda Devi simply because it's a wonderful read.
                                As the Crow flies

                                "Buy the ticket, take the ride"

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