Posted on 11/16/2001 1:19:06 PM PST by The Magical Mischief Tour
This is Bull $h!t!!!
The NTSB is LYING like rugs!!!
NTSB dude just claimed that .3 to .8 g's encountered during the wake encounter caused the Airbus to break up in flight...
Even a male reported asked "is this even possible".
"Isn't this normal bumping encountered when flying?"
Even the media don't believe them!!!!!
My God! A Cessna 172 can withstand 3 times that amount with no problem!
Neither background is required to substitute common sense, and make the observation that the King has no clothes.
Sorry, but every standard building code requires a safety factor of at least 1.7x required loading.
There are safety margins. There generally is not redundancy. Safety margins and redundancy, while related, are two very different concepts.
The safety margin of a design is the factor by which a load or stress must exceed the design specification before a failure results. If a balcony has a design rating of 500lbs and has a safety factor of 2, that means that it will support at least 1,000lbs of stationary loading.
Redundancy is the extent to which a design can withstand the failure of a part for reasons other than excess loading.. Generally, failures due to excessive loading will propagate even in systems with redundancy, since the failure will result in other parts of the system being subjected to loads even worse than the part that failed.
Two examples should illustrate pretty well the difference between redundancy and safety factor. For the first example, consisder a small triangular platform, 10 feet on a side, whose rated load (including its own weight), is 500lbs. Further, suppose that it is supported at each corner by ten small, slightly-elastic ropes, each of which will withstand up to 20lbs. If the ropes are slightly elastic, the tension on all the ropes on each corner will be roughly comparable. If any rope fails, the others supporting that corner will all have their stress increase by 11%.
In this example, there is redundancy: if a rope failed for a reason other than overloading (e.g. someone cut it), then provided even with the platform fully loaded the other ropes would probably be able to make up for the failed one. The static-load safety margin of the system is 20% (the safety factor is 1.2), but would drop to 8% after a rope failed. Still probably survivable, but dynamic loads in such a case could easily exceed the ropes' yield strength. On the other hand, if the platform were loaded to only half of capacity, it would without a doubt withstand the loss of a rope with no problem whatsoever.
Now consider that the same platform is supported by one rope in each corner, but the ropes can support 500lbs each. The static-load safety margin is now 200% (the safety factor is 3.0). But what happens if a rope fails? Even if the platform is loaded to only a quarter of its rated load, the failure of a single rope will cause the structure to fail. There is a much greater safety margin than in the first example, but no redundancy.
Unfortunately, redundancy is often a lot more expensive to design in than a significant safety margin. Imagine that someone builds narrow platform 50 feet long by 2 feet wide by taking a 50'x2'x2" board and supporting it every 5 feet. Depending upon the type of wood, such a platform will support some level of worst-case loading. Call that l.
Suppose someone wanted to improve the design of the platform so it could withstand the loss of any single support other than one of the ends. How much stronger would the material have to be in order to withstand such loss?
The material would have to be four times as strong to survive undamaged the loss of a single one of its eleven supports while fully loaded. While the platform, constructed as described, would be able to survive the loss of a support when lightly loaded, it would have to have a four-fold safety factor to survive such loss when fully loaded.
Actually, the single-board platform probably had better redundancy than many structures, since any part of the board can withstand beam action. Imagine if instead the constructor had used two 25' boards rather than one 50' board, and designed the central support to adequately support the two board ends that met in the middle. Now what happens if that support goes away?
The resulting cantilevered board ends will have almost no strength. Given that the weight of the board itself will remain constant, the boards will not be able to handle more than a small faction of the loads which they could earlier handle quite easily. Put any load at all on such a damaged structure and it will fail completely. Indeed, even the mere weight of the board itself may be too much for the structure to withstand.
BTW, the World Trade Center's design exhibited much better redundancy than most skyscrapers. While the planes were able to damage huge numbers of adjacent structural supports, the buildings remained standing for quite awhile until fire weakened too greatly those that remained.
Maybe you spent too much time in law school. FR is full of pilots who are not AEs but quite capeable of rendering a reasonable and educated opinion based on some relevent education and lots of relevent experience.
That's true. It was a composite failure though in the tail. It had been previously repaired, but apparently not well enough. Also a simple matter of the documented record, and the composite is sure ripped right apart with the bolts all neatly still in place. I believe they referred to it as a delamination. Looked a lot like a torn piece of parchment with all the fibres frayed away unevenly.
TRENTON, N.J. (Reuters) - The New Jersey Lottery will pay out more than $1 million to thousands of lottery winners who bet on the flight number of the jetliner that crashed in New York this week, lottery officials said on Tuesday.
American Airlines Flight 587 plunged into a quiet Queens neighborhood on Monday morning, killing all 260 people aboard the Airbus A300 in a fiery air disaster that shook New Yorkers with fears of a deadly new attack almost exactly two months after Sept. 11.
Hours later, not only did "587" turn out to be the winning number in the New Jersey Lottery's Pick-3 game, but players wound up buying a whopping 27,829 winning tickets. They each won $16, and the money won by other types of tickets that also contained the flight number pushed the total payout over $1 million.
The macabre twist of fate did not end there, however, because a slight variation on the plane's flight number -- 578 -- had also been the winner in a midday lottery drawing.
Virginia Haines, executive director of the New Jersey Lottery, said the matching numbers were an obvious rarity. "Since I've been director, for over seven years, it's the first time this has happened with Pick-3," she said.
Am old newsie. There was a sign in old City Press Room in Chicago:
100% cover-up if this story remains the same, and Bush will not be forgivin for lying to us. He had better come clean, before it's too late..
Regarding what happened to Airbus #587 American Airlines Flight that crashed in Rockaway Beach Queens , N.Y.
I believe if it were sabotage the perpetrators would wait until the aircraft was parked in an isolated area, such as,a hangar or runway.Then they would run a blow torch or such, along every seam,on the wings, vertical stablizer,tail section, and engines to where they were attached to the fuselage.
Then spray paint over the burns, which have weakened the metal. This scoring would take effect when stress would be applied to the aircraft such as wind pressure on take off. This would cause the sections to break away.
This is my theory. Hopefully I am wrong.
I've been an aircraft electrician for 20 years now on A-6E, F/A-18, F-16, and now C-130 type aircraft. Your entire statement was exceptionally well written; quite expressive. The only issue that I have is that you have made the assumption that stab aug failed. If there was a massive failure of all fcs channels then it would be recorded on the flight data recorder.
I think it was sabotage.
The "g" figures are a measure of the acceleration of the instrument itself. You could be holding it in your hand waving it around, for all it knows. It doesn't tell you anything directly about the stress on the joint between the vertical stabilizer and the fuselage.
I am pretty ignorant on all of this but the reason I am asking this is is it possible that if the vertical stabilizer was just beginning to become loose during a turn, would the sudden change in the angle from 90 degrees (perfectly perpendicular) be sufficient to reduce the lateral drag enough to allow the plane to shift sideways dramatically enough to cause whatever is measuring the forces to perceive this as additional force rather than the plane moving due to the decreased lateral resistance?
This is what I'm inclined to believe - the shaking and movement of the plane was due to the tail starting to "flap". I guess we'll start seeing more detailed diagrams of the tail joint in the papers, but I think it's anchored with a long "tab" parallel to the axis of the fuselage. The "tab" is composite material and very strong. However, if the fuselage itself had started to give way around the base, this could have allowed some lateral movement of the tail, which may have been imperceptible at first, but then amplified by the slipstream when it reached a critical level. To me, this could explain why such a strong material could have given way so suddenly. It's exactly what you do when you're trying to break a joint like that - wobble it back and forth.
http://www.ntsb.gov/Events/2001/AA587/tailcomp.htm
Looks like the attachments for the vertical part of the tail are all composite. I think there are six. One of the pins seems to be missing, but the rest all have remnants of the composite tail structure left. My guess is that was previously weakened and it was knocked off by the wing tip vortix from the plane ahead. It is possible that composite structures can be damaged internally and not show many signs of that externally. Conventional inspection techniques (ultrasonics, eddy current) probably do not work well or at all on composites.
Unbelievable. You need to calm down.
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