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  • #46
    Originally posted by Evan View Post

    By the way:

    Click image for larger version  Name:	1968108.jpg Views:	0 Size:	560.6 KB ID:	1109841
    Thought you were talking about the hatch in the cockpit. While you have the picture, look at the designation on the nose. Do you see 747-800?

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    • #47
      Originally posted by Gabriel View Post

      Yet, whenever I can get one, I always pick an outward-opening emergency exit row in the 737.
      Not my favorite aspect of the NG's but look, emergency exits are so rarely used that the risk of the lock mechanisms failing is insignificant. I concede that the benefit of not having to stow the door in the cabin during an emergency probably outweighs the added risk of it not being a plug. If these were getting opened and shut between every cycle I would feel differently.

      One potential concern is that these doors are locked by an electronic system that requires power to remain in the locked position. What happens if the system loses power for some reason? There is still the lever position, which hopefully engages a second, mechanical lock, but that would leave the door one passenger lever pull away from opening in flight. This provides some detail:

      http://jdasolutions.aero/blog/firefi...ll-wing-exits/

      Comment


      • #48
        Originally posted by BoeingBobby View Post

        Thought you were talking about the hatch in the cockpit. While you have the picture, look at the designation on the nose. Do you see 747-800?
        Yes, captain. You can't blame people for calling it the -800 though after the -100, -200, -300 and -400. 747-8 looks like a typo.

        Comment


        • #49
          Originally posted by Evan View Post

          Yes, captain. You can't blame people for calling it the -800 though after the -100, -200, -300 and -400. 747-8 looks like a typo.
          And the SP and LCF ? Another "typo?"

          Comment


          • #50
            Originally posted by Evan View Post
            Right. And yet... how many have opened in flight? Every one of them was 'well-designed' until the weakness revealed itself.
            I disagree. Look the 747 incident. They designed locking sectors to prevent the cam to rotate, except the locking sectors were too weak to prevent the cams to rotate.
            That is bad design from scratch, not an obscure unforeseen circumstance that the engineers could not have considered until it revealed itself.

            And sometimes that weakness was a lax mechanic or a rampie with a rubber hammer solution to life's little problems or an operator pushing limits.
            Again, I disagree. The design should and CAN be made not only fail safe, but also fool-proof. You know, like the plane won't take-off unless the door is properly closed and the door will not pop open when it is properly closed. The design INTENTION (design input, as we call them) of the CD-10 and 747 doors included that, but the design itself (the design output) did not comply with the input. And after some non-deadly incidents and some deadly accidents, both of them were fixed for good with things that should have been designed from the beginning. Again, not obscure things.

            Next you will say that the MCAS was a god design until the weakness revealed itself.

            It all comes into play. In the final analysis, its far better to fail inward. (note the little dot)
            I agree with that. Do you know what else would be better? Not to have a pressurized hull. That caused several deadly accidents (with the number of deaths in the many hundreds, if not in the thousands already) that definitively would not have happened if the planes were not pressurized. And that's just an example. I could talk about many things that "cold be done safer".
            But, alas, economical and practical limitations do exist.

            Certification being what it is, non-plug, outward-opening doors were allowed in the interest of affording more cargo space.
            You don't know that, or prove me wrong. I don't know that either, but I very much doubt that "non-plug, outward-opening doors were allowed in the interest of affording more cargo space", or in the interest of anything else. I rather think that there was never a consideration to allow or disallow any particular type of door.

            Once one airframer had this to offer, the others would have to as well. So they are quite common now.
            Again, you are talking as if there was a time where the doors were all plug-type and suddenly one airframer came up with the brilliant idea of making an outwards-opening door.
            DO you know that to be the case? Which was that instance?


            But they still fail, again and again, from the 60's to the current day.
            Some designs do. Some designs never ever did even once despite being many thousands of them flying every day. When was the last time you heard of an A320 FWD or AFT cargo holds door opening in flight? (and it is just one example)
            The 747 and DC-10 doors never failed again after the mods.

            What is unacceptable is that the industry is not more careful with the design and, even worse, that when an incident happens, it is not taken seriously until there are deaths. Happened with the 747, DC-10 and DC-9. Seems to be happening with the 757 (although I don't know the details)

            --- 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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            • #51
              Originally posted by Gabriel View Post
              I disagree. Look the 747 incident. They designed locking sectors to prevent the cam to rotate, except the locking sectors were too weak to prevent the cams to rotate.
              That is bad design from scratch, not an obscure unforeseen circumstance that the engineers could not have considered until it revealed itself.


              Again, I disagree. The design should and CAN be made not only fail safe, but also fool-proof.
              I agree, of course. But that's not how reality works. The designs for the 707, DC-9, DC-10, 747, 757 and whatever others aircraft have been affected were not known by the FAA or the flying public to be unsafe until after the weaknesses revealed themselves. So, the same could be true of the 777, 787, A350 et al. You are correct that the designs were not safe, but you wouldn't have known that when climbing aboard a 747 in 1985. I agree that certain aircraft such as the A320 appear to have safe door systems. given the years in service. But then, the B747 had been in service for two decades when the door on United Flt 811 failed in flight. As I said before, I hope that the lessons were learned and the weaknesses eliminated and redundancies added over the past three decades.

              But then here we are: it's still happening! Not baggage doors, thank the gods, but large cargo doors. If the problems were worked out, how is that possible?

              Again, inspiring this argument was my statement that I avoided combis, not that I avoid aircraft with outward-opening baggage doors (because that would be impossible in 2021).

              Now that the combis are phased out, unless I'm flying to Nepal or on some rare charter, it's no longer a problem.

              You don't know that, or prove me wrong. I don't know that either, but I very much doubt that "non-plug, outward-opening doors were allowed in the interest of affording more cargo space", or in the interest of anything else. I rather think that there was never a consideration to allow or disallow any particular type of door.
              It's a hard thing to research, but AFAIK, the first generation of pressurized turbojet airliners, such as the B707 and the DC-8 used plug-type baggage doors for safety reasons. The B727 is the first major airframe that I know of to use the outward-opening baggage doors. I'm not claiming that the FAA or the FAR's ever mandated inward opening doors. I'm suggesting that, when airframers decided to use outward-opening doors, the FAA could have rejected the designs but did not, knowing that the designs were less safe, for reasons that I believe were related to the benefit of more efficient use of interior space and the practical generation of revenue: a compromise between safety and commercial viability.

              Hundreds of people paid the price with their lives.

              Comment


              • #52
                Originally posted by Evan View Post
                thank the gods
                Just curious, how many of them are there?

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                • #53
                  Originally posted by BoeingBobby View Post

                  Just curious, how many of them are there?
                  Thirteen including you.

                  Comment


                  • #54
                    Originally posted by BoeingBobby View Post

                    Just curious, how many of them are there?
                    A friend of ATLCrew may know of several.
                    Les rčgles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                    Comment


                    • #55
                      Originally posted by Evan View Post
                      I agree that certain aircraft sch as the A320 appear to have safe door systems. given the years in service. But then, the B747 had been in service for two decades when the door on United Flt 811 failed in flight.
                      Random quotes from an article that you referenced (I'll try to quote them in historical order).

                      Deficiencies in the design of wide-body aircraft cargo doors were known since the early 1970s from flaws in the DC-10 cargo door.[14][15] These problems were not fully addressed by the aircraft industry or the NTSB, despite the warnings and deaths from the DC-10 accidents[16] and attempts by Boeing to solve the problems in the 1970s.

                      As early as 1975, Boeing realized that the aluminum locking sectors were too thin a gauge to be effective and recommended the airlines to add doublers to the locking sectors.

                      In 1987, Pan Am Flight 125, another Boeing 747, outbound from London Heathrow Airport, encountered pressurization problems at 20,000 feet (6,100 m), causing the crew to abort the flight and return to the airport.[1]:57[11] After the safe landing, the aircraft's cargo door was found to be ajar by about 1.5 inches (3.8 cm) along its ventral edge. When the aircraft was examined in a maintenance hangar, all of the locking arms were found to be either damaged or entirely sheared off. Boeing initially attributed this to mishandling by ground crew. To test this concern, Boeing instructed 747 operators to shut and lock the cargo door with the external handle, and then activate the door-open switch with the handle still in the locked position. Since the S-2 switch was designed to deactivate the door motors if the handle was locked, nothing should have happened. Some of the airlines reported the door motors did indeed begin running, attempting to force the door open against the locking sectors and causing damage to the mechanism.

                      After the 1987 Pan Am incident, Boeing issued a Service Bulletin notifying operators to replace the aluminum locking sectors with steel locking sectors, and to carry out various inspections.

                      In the United States, the FAA mandated this service by means of an Airworthiness Directive (AD) in July of 1988 and gave U.S. airlines 18 to 24 months to comply with it.

                      On February 24, 1989, the Boeing 747-122 serving the flight [United Airlines Flight 811] experienced a cargo door failure in flight shortly after leaving Honolulu, resulting in the deaths of nine passengers.

                      After the Flight 811 accident, the FAA shortened [AD compliance] the time to 30 days.
                      The design, as you can see, is not the only thing that was flawed.


                      I'm not claiming that the FAA or the FAR's ever mandated inward opening doors. I'm suggesting that, when airframers decided to use outward-opening doors, the FAA could have rejected the designs but did not, knowing that the designs were less safe, for reasons that I believe were related to the benefit of more efficient use of interior space and the practical generation of revenue: a compromise between safety and commercial viability.

                      Hundreds of people paid the price with their lives.
                      Again, I disagree. Think of flight control computers. How dangerous can they be if nor well designed and tested. But you don't say that the FAA should ban flight control computers because of examples like the MCAS for which hundreds paid with their lives, right?

                      What I would say is:
                      - Manufacturers should do good design, and test it correctly.
                      - The FAA should be harder to convince that a design is good (be it a door or a flight control computer).
                      - Upon the first indications of bad design in a type already certified, the industry (led b the FAA) should act promptly to assess the safety implications and act decisively to protect the flying public.

                      Do you want "me" to approve this door? Fine, convince "me" that, even in cases of human error during operations, the plane will not take off with the door not properly closed and that it will not open in flight. "It is a plug door for the sake of the gods" is a good start, but that in itself is not enough to convince "me", nor is it required to convince "me".

                      --- 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


                      • #56
                        Originally posted by Gabriel View Post
                        Again, you are talking as if there was a time where the doors were all plug-type and suddenly one airframer came up with the brilliant idea of making an outwards-opening door. DO you know that to be the case? Which was that instance?
                        Best I can tell thus far, the B707, DC-8, DC-9/MD-80 and 737-100/200 had all plug-type cargo doors (all doors). The first time I see outward-opening cargo doors is on the 727.

                        Comment


                        • #57
                          Originally posted by Gabriel View Post
                          The design, as you can see, is not the only thing that was flawed.
                          Indeed. It never is. That's my point.

                          Again, I disagree. Think of flight control computers. How dangerous can they be if nor well designed and tested. But you don't say that the FAA should ban flight control computers because of examples like the MCAS for which hundreds paid with their lives, right?
                          But flight control computers make aviation much safer in general. The trade-off in risk vs reduction of risk is a no-brainer. There is no safety trade-off in moving away from plug-type cargo doors. It is simply less safe by its very nature. Nevertheless, research the story of how many hoops and levels of assurance Airbus was required to provide before gaining certification for FBW. It's inspiring. I'm convinced there will never be a crash resulting from a failure of flight control on these aircraft because the process was so cautiously considered and the system so overbuilt.

                          MCAS was a different story. A crime really.

                          Comment


                          • #58
                            Originally posted by BoeingBobby View Post
                            Is it possible to paradrop cargo from commercial freighters? Would've resulted in cost savings. I guess not possible, otherwise Ryanair would've started a freighter venture by now.
                            ''It is highly speculated that the Il-76 was not chosen as the leading actor in The Transporter movies only because Hillary Clinton and Harvey Weinstein were not okay with it being Russian, and the role eventually went to Jason Statham instead.''
                            Fantastic Planes and How to Identify Them by Ahnaf Ahmed
                            Link: https://books2read.com/FantasticPlanes

                            Comment


                            • #59
                              Originally posted by Winglet_Flanker View Post

                              Is it possible to paradrop cargo from commercial freighters? Would've resulted in cost savings. I guess not possible, otherwise Ryanair would've started a freighter venture by now.
                              Good when you can answer your own question

                              Comment


                              • #60
                                Originally posted by 3WE View Post
                                Speculation:

                                Originally posted by Someone in the 1990s

                                ACHTUNG! ALLES LOOKENSPEEPERS!

                                Alles touristen und non-technischen looken peepers!
                                Das computermachine ist nicht fuer gefingerpoken und mittengrabben.
                                Ist easy schnappen der springenwerk, blowenfusen und poppencorken
                                mit spitzensparken. Ist nicht fuer gewerken bei das dumpkopfen.
                                Das rubbernecken sichtseeren keepen das cotten-pickenen hans in das
                                pockets muss; relaxen und watchen das blinkenlichten.
                                LOL.

                                Sag mal, versuchst Du mich mit Deutschkenntnissen zu beeindrucken? Definitiv gelungen. gefingerpoken. Das klingt wirklich leicht anzüglich, aber in Deutschland ist es gerade 04:39 a.m.
                                Die Uhrzeit für nicht jugendfreie Themen. Was sagt Deine Frau zu gefingerpoken?

                                Back on topic.

                                Thank You to our dear friend Gabriel, who always mentions the reliable link:
                                http://avherald.com/h?article=47e66828&opt=0

                                Hm. And something like that was able to happen on a 757, in the year 2014?!

                                That reminds me of an incident on board a 747:
                                https://en.wikipedia.org/wiki/United...nes_Flight_811

                                355 souls on board, And only because of the extraordinary skills of the experienced 747-100 (!) Fligth Captain David Cronin, he was one of 346 survivors of that flight.
                                Date of the flight was February 24th 1989.
                                My favorite beverage seller a few days ago said, oha, you don't really seem that old. And I really took it as a compliment. But it is the truth, 43, since almost 48 hours already..

                                Yes. And aviation enthusiast since more than 35 years.
                                The German long haul is alive, since more than 60 years.
                                The Gold Member in the 747 club, 50 years since the first LH 747.
                                And constantly advanced, 744 and 748 /w upper and lower EICAS.
                                Aviation enthusiast, since more than 35 years with home airport EDDL.

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