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Boeing 737-800 Question
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| bar_rodoy | Дата: Пятница, 05.08.2011, 04:27 | Сообщение # 1 |
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| I apologize ahead of time if this has been talked about or is a dumb question but are 738 built to break near the front wing box during a crash or overrun? The three plane crashes that come to mind are TK at AMS, AA at KIN and BW at GEO
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| b-747 | Дата: Пятница, 05.08.2011, 04:29 | Сообщение # 2 |
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| They're not built to break there. That's just the point of maximum stress. It's a beam supported at one end by the main landing gear and at the other end by the nose landing gear. The impact load comes in at the gear and you have a large inertial load going down...that causes a lot of bending on the fuselage and, in pure bending, the maximum stress is at the midpoint.
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| @737@ | Дата: Пятница, 05.08.2011, 04:30 | Сообщение # 3 |
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| This subject was raised in a previous post, I believe in June. Sorry people - I searched but could not find it.
The subject of 737NG failures was raised in the Australian Dateline program. Below is a brief summary of the investigation as broadcast:
"Could airline giant Boeing really have allowed ill-fitting and dangerous parts into the construction of some of its 737 planes, potentially risking the lives of passengers?
Dozens of the planes are in Australian skies and there have been three suspicious crashes elsewhere in the world, but an investigation screened on Dateline alleges that Boeing and the United States authorities have taken little action.
Two former Boeing employees turned whistleblowers, Gigi Prewitt and Taylor Smith, are at the heart of the story.
They say they couldn't keep quiet any longer over defective parts being made by a subcontractor, Ducommun, which they say were then allowed into 737 Next Generation planes between 1996 and 2004… some even had to be hammered into shape or packed with filler to make them fit.
Their allegations have been all the way to the US Department of Justice, the Federal Aviation Administration and the Defence Criminal Investigative Service – all have dismissed them, with Boeing saying they’re ‘without merit’.
But Tim Tate's special investigation alleges conflicting information, intimidation, collusion, and ultimately aeroplanes that are unfit to fly. So are we really safe in the skies?"
Here's a link to the Dateline site - worth a look based on yet anohter incident...
http://www.sbs.com.au/datelin....-Prayer
Can anyone confirm the manufacture date of the aircraft in question?
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| bar_rodoy | Дата: Пятница, 05.08.2011, 04:30 | Сообщение # 4 |
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| I was always told that that is exactly where it is supposed to break. I remember hearing that it's supposed to break in 3 sections during this kind of event.
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| Tu-154B-2 | Дата: Пятница, 05.08.2011, 04:31 | Сообщение # 5 |
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| So B737NGs built from 2005 do not have these defective parts?
Если мальчик любит труд- значит звать его "Джамшут"
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| Tu-154B-2 | Дата: Пятница, 05.08.2011, 04:32 | Сообщение # 6 |
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| So the defective parts failed only on impact? What silly allegations!
Если мальчик любит труд- значит звать его "Джамшут"
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| cassini-m | Дата: Пятница, 05.08.2011, 04:33 | Сообщение # 7 |
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| Indeed. And the US regulating bodies, which have no problem grounding entire narrowbody fleets for something as (compared to fuselage failures) minor as wire bundle tie locations, is turning a blind eye on death trap airplanes built for ten years? I hardly believe that for even a minute.
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| capitan_cg | Дата: Пятница, 05.08.2011, 04:33 | Сообщение # 8 |
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| Quote (Tu-154B-2) So the defective parts failed only on impact? What silly allegations!
Although, I would be also worth noting that somehow the majority of the passengers and crew walked away from all the creashed you mention. As we say in avaiation: "Any landing that you can walk away from is a good landing!"
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| @737@ | Дата: Пятница, 05.08.2011, 04:34 | Сообщение # 9 |
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| That's not the same subject. Even if you accept the Dateline story (I don't, but that's a different issue) it's not germane to the question of this thread. It is *not* a defect for an aircraft to break up when the landing overloads the structure. That's just what you expect.
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| Гость | Дата: Пятница, 05.08.2011, 04:34 | Сообщение # 10 |
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| BIG difference between "where it's supposed to break" and "it was built to break there"
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| bar_rodoy | Дата: Пятница, 05.08.2011, 04:37 | Сообщение # 11 |
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| you will note that they didn't break in exactly the same place. (count the windows).
They are roughly in the same place for a good reason, the portion of the fuselage with the wingbox is right behind it and is much stronger/stiffer than the section that breaks. You really do not want to fly a plane that ISN'T build stiffer and stronger in the wingbox region as this area handles huge areodynamic loads that don't affect the rest of the fuselage at all.
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| @737@ | Дата: Пятница, 05.08.2011, 04:38 | Сообщение # 12 |
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| thank you all everyone for your insight and answers
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| b-747 | Дата: Пятница, 05.08.2011, 04:39 | Сообщение # 13 |
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| Correct!
If you look at the picture of the American 737 in the original post, it also broke just aft of the wings. Again where the stronger/stiffer section ends.
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| Tu-154B-2 | Дата: Пятница, 05.08.2011, 04:39 | Сообщение # 14 |
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| Avoid row 10 seems to be the best option!
Если мальчик любит труд- значит звать его "Джамшут"
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| Xiao | Дата: Пятница, 05.08.2011, 04:42 | Сообщение # 16 |
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| Over the wing seats are some of the best seats in the house when it comes to overruns and crash landings. As has been mentioned before this is where the fuselage is at its strongest because the wing box is there and it is built to withstand very high loads. Which is why when the way in which a wing box is built is changed/updated its a big deal, eg. The A380 wing box which was build with composite material as a first to save quite a percentage in weight in comparison with previous practices.
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