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ejoiner

Opening doors inflight

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Every now and then I read news stories about unruly passengers who try to open up doors on a commercial airliner while in flight. My question is can they be opened or are there mechanical safeguards in place to prevent them from being opened while in flight or if the cabin is pressurized?

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With Boeing aircraft it is next to near impossible to get them open while in flight, but it can be done (D.B Cooper hijacking although this was out of the rear drop down 727 door). Boeing aircraft have the door come inside the fuselage and then when closed are pushed against the door frame. It is then locked into place what is different is that when pressurization takes effect it pushes the door harder against the frame making it hard to open.I know Airbus leased a Boeing airplane once to see exactly how to make the door. So they may use something similar to Boeing but I have no mechanical exprerience with the scarebus.

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I'm sure AIRbus builds their doors in a similar fashion. Not because they "ripped off Boeing" or anything, but because it's practical.

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>With Boeing aircraft it is next to near impossible to get>them open while in flight, but it can be done (D.B Cooper>hijacking although this was out of the rear drop down 727>door). Boeing aircraft have the door come inside the fuselage>and then when closed are pushed against the door frame. It is>then locked into place what is different is that when>pressurization takes effect it pushes the door harder against>the frame making it hard to open.>>I know Airbus leased a Boeing airplane once to see exactly how>to make the door. So they may use something similar to Boeing>but I have no mechanical exprerience with the scarebus. What you said abouth the doors is mostly true. The rest seems unlikely. Not all doors on Boeings open inwards - the cargo doors on the 747F open out, although they have to be specially locked in place. Also, the concept of the doors opening inwards in order to make them safer (or more difficult to open) is hardly reaching, even for an Airbus engineer. I'm sure that they are aware of the unequalized pressure on each side of the door, and the opportunity to use this to make the door stay closed.I'm curious how you "know" that Airbus leased a Boeing to see how they made thier doors. If it were really that clever, surely Boeing would have patented it and Airbus wouldn't be able to use it. Also, why would they bother leasing a whole plane? Why not just buy some service manuals and actually read the gory details? Why not just walk up to one of their customers and simply ask to look at the doors on one of their Boeings?It seems kind of silly, but if you do have a reference for any o this, I would be interested in reading it.- Martin

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No the doors open outwards but come back through the opening and then enlarge and close up the hole. It is interesting to watch and I still don't understand it after reading through all the spec charts.I can't really say who I get the information from but both people (one which I am son of) work for Mullally

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>No the doors open outwards but come back through the opening>and then enlarge and close up the hole. It is interesting to>watch and I still don't understand it after reading through>all the spec charts.>>I can't really say who I get the information from but both>people (one which I am son of) work for Mullallyummm... this Mullally?http://www.meganmullally.net/What does that mean? What does she know about Airbus?

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Morning,To understand Plug Doors on aircraft, you must first think of a man hole cover. As a circle is the only geometric shape that will NOT fall through it's own hole. All the rest, triangle, rectangle, etc. will. All you have to do is turn it. So, if a round plug is made with the OD slightly larger than the hole diameter, you have a nice door that will not blow out. Now, most aircraft doors are rectangle. For the rectangle plug door to to be opened from the inside to the outside, we just turn it a little through the support hinge linkage, and the door slips right outside, and up against the fuselage. Neet ah!Regards,Bob...... Very old maintenance guy

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>>No the doors open outwards but come back through the>opening>>and then enlarge and close up the hole. It is interesting to>>watch and I still don't understand it after reading through>>all the spec charts.>>>>I can't really say who I get the information from but both>>people (one which I am son of) work for Mullally>>ummm... this Mullally?>>http://www.meganmullally.net/>>What does that mean? What does she know about Airbus?>>Himhttp://www.boeing.com/nco/mulally.html

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>>>No the doors open outwards but come back through the>>opening>>>and then enlarge and close up the hole. It is interesting>to>>>watch and I still don't understand it after reading through>>>all the spec charts.>>>>>>I can't really say who I get the information from but both>>>people (one which I am son of) work for Mullally>>>>ummm... this Mullally?>>>>http://www.meganmullally.net/>>>>What does that mean? What does she know about Airbus?>>>>>>>Him>>http://www.boeing.com/nco/mulally.htmlAhhh... I guess if you had gotten the spelling right the first time, I would have found "him" instead of "her" when I did my search. Notwithstanding that fact, lineage does not equal proof, in my world, even if Mr. Mulally said so. The manhole cover analogy was a good one, and that was an enlightening post. If you search for United Flight 811, you find that on that Boeing 747, the cargo door did open outwards, which malfunctioned and opened in flight, causing explosive decompression. A result was a design change that resulted in the doors opening inwards, as described by Bob.http://www.ntsb.gov/publictn/1992/aar9202.htmhttp://en.wikipedia.org/wiki/United_Airlines_Flight_811

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Oh I am so sorry I spelled his name wrong and that my sources have everything to do with the mechanics invented for the door to work. I forgot direct sources have no place "in your world".Also what you are referring to doesn't have anything to do with the topic at hand of a passenger opening a passenger door. Although very similiar, they do not open in the same way.

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>>. If you search for United Flight 811, you find that on that Boeing 747, the cargo door did open outwards, which malfunctioned and opened>> in flight, causing explosive decompression. A result was a design change that resulted in the doors opening inwards, as described by Bob.Not so. The actual solution in the 747's case was to make the locks stronger. The reason the cargo doors open outwards is so the maximum amount of cargo can be loaded (if it opened inward, you wouldn't be able to put a cargo container right by the door as there wouldn't be room to close the door.The problem with the 747 was that it used electric motors and alluminium locks. The alluminium was far to weak for the job and tests found that if the electric motors shorted out and engaged, they were powerful enough to open the doors even with the locks in place. This was known about before the accident and Boeing's solution was that the locks should be doubled in thickness to be stronger, but as usual in the airline industry, these safety measures are put into place over a period of time, generally only when the aircraft is out of service for regular maintenance.Anywa, the cargo doors on the 747, 757, 767 and 777 all open outwards.Its not quite as safe as the plug design as it is not redundant (if the locks break, the door will fly open rather than be kept shut by the force of the compressed cabin) but the cargo capacity is more important than that. Its still safe ofcourse, just not redundant.777 photo for examplehttp://www.airliners.net/open.file/1018262/L/

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>Not so. The actual solution in the 747's case was to make the>locks stronger. ...>777 photo for example>http://www.airliners.net/open.file/1018262/L/So I was correct when I made my original post when I said that the cargo doors on the 747 open out? I have an open mind, and in another post, Bob did a good job of explaining how modern cargo doors actually open inwards. My original post stated that the cargo doors opened outwards, like you just said, but Bob's post and the NTSB report showed me that the information wasn't necessarily current, and that flight 811 was a catalyst for change. The photo doesn't show the doors opening, it just shows them in their final position, which is naturally on the outside of the plane. From what I understand about what Bob said (and I have no reason not to believe him) the door opens inwards, and then angles slightly to get out of it's hole and then swing outwards. Maybe Bob was wrong, (which would mean that I was initially right), but his explanation seems reasonable.

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737 cargo doors do open completly inwards, as do CRJ's and the BAe-146. Generally smaller aircraft that don't carry large cargo containers and where maximum cargo capacity isn't as essential.http://www.airliners.net/open.file/0715928/L/I can't be technical in the exact function of the doors, I'm not an engineer so I'll admit I can but wrong about that, but the reason for the United Crash was to do with the latches opening. They first thought the it was to do with faulty maintaince, but after recovering the cargo door it was found to be a design issue."The door opening was attributed to a faulty switch or wiring in the door control system which permitted electrical actuation of the door latches toward the unlatched position after initial door closure and before takeoff. Contributing to the cause of the accident was a deficiency in the design of the cargo door locking mechanisms, which made them susceptible to deformation, allowing the door to become unlatched after being properly latched and locked. Also contributing to the accident was a lack of timely corrective actions by Boeing and the FAA following a 1987 cargo door opening incident on a Pan Am B-747."

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>"The door opening was attributed to a faulty switch or wiring>in the door control system which permitted electrical>actuation of the door latches toward the unlatched position>after initial door closure and before takeoff. Contributing to>the cause of the accident was a deficiency in the design of>the cargo door locking mechanisms, which made them susceptible>to deformation, allowing the door to become unlatched after>being properly latched and locked. Also contributing to the>accident was a lack of timely corrective actions by Boeing and>the FAA following a 1987 cargo door opening incident on a Pan>Am B-747."That's all true, and no one is debating that. The reason for the mention of the inward-opening doors in the NTSB report was that it was felt that this could have helped prevent the doors from opening. I.e., was the motor strong enough to deform the latches AND work against the internal pressure of the airplane? Maybe, maybe not. It's just an extra level of redundancy that hopefully improves the safety of the design.

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