AirBus crash info
Dec 7, 2001, 9:27 am
#1
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AirBus crash info
Hi!
This was forwarded to me by Bob Funk, an ex-Canberra spy plane pilot who flew missions over China in the 60's. Interesting view on the recent Airbus crash.
Subject: Fw: Failed Composite Material - Airbus Crash
This interesting analysis is from a Marine MG (Ret'd). Gary Wheeler has dedicated his life to aerodynamics. He invented the Wheeler Vortex generator, and the "Gurney" wing on race cars. These are his views on the crashed Airbus:
Re: the New York 11-12-2001 Airbus crash.
I found a photo of the vertical stabilizer's failed composite attachment blades or webs. The bolts that attached the composite vertical stabilizer to the fuselage, remain properly attached. Clearly, the failure is a delamination of the composite vertical tail above the points of attachment to the fuselage.There are reasons (despite the weight savings) why Douglas Aircraft and Boeing never used composites this way - and you're looking at one.
As the delamination of the composite progressed, the entire 37-ft. tall vertical tail would have fluttered briefly and violently. That would explain why both engines were literally shaken off the airplane. This is particularly remarkable, because unlike Douglas and Boeing, Airbus has bragged of purposely designing their engine mounting pylons to keep the engines in place no matter what!) One wing tip was found several blocks away from the main wreckage.
BTW, you'll be hearing a lot about an encounter with wake turbulence.That is a red herring. Wake turbulence can make it difficult - maybe even impossible to control the airplane - but no amount of wake turbulence can remove the vertical tail at such low flight speeds unless there is a pre-existing structural fault.
What is flutter? This morning, I got an email from a friend who is the Director of Structural Engineering of a major American aircraft maker. He described a chilling picture: "Flutter modes often have an explosively quick onset, rising from nothing to catastrophic in the blink of an eye. Furthermore, the shaking can happen so fast that, despite the large (huge) deflections involved, an observer on the ground might not see it. It's just a blur. The people in the back of the airplane would have been
homogenized back there; but it was all over a few seconds later."
The design weakness can and will be fixed on other Airbuses. If not, there are plenty of nice Boeing jetliners mothballed in the Mojave Desert, that can trade places with the Airbuses. In the meantime, I'm not riding Airbus.
------------------
Brian
This was forwarded to me by Bob Funk, an ex-Canberra spy plane pilot who flew missions over China in the 60's. Interesting view on the recent Airbus crash.
Subject: Fw: Failed Composite Material - Airbus Crash
This interesting analysis is from a Marine MG (Ret'd). Gary Wheeler has dedicated his life to aerodynamics. He invented the Wheeler Vortex generator, and the "Gurney" wing on race cars. These are his views on the crashed Airbus:
Re: the New York 11-12-2001 Airbus crash.
I found a photo of the vertical stabilizer's failed composite attachment blades or webs. The bolts that attached the composite vertical stabilizer to the fuselage, remain properly attached. Clearly, the failure is a delamination of the composite vertical tail above the points of attachment to the fuselage.There are reasons (despite the weight savings) why Douglas Aircraft and Boeing never used composites this way - and you're looking at one.
As the delamination of the composite progressed, the entire 37-ft. tall vertical tail would have fluttered briefly and violently. That would explain why both engines were literally shaken off the airplane. This is particularly remarkable, because unlike Douglas and Boeing, Airbus has bragged of purposely designing their engine mounting pylons to keep the engines in place no matter what!) One wing tip was found several blocks away from the main wreckage.
BTW, you'll be hearing a lot about an encounter with wake turbulence.That is a red herring. Wake turbulence can make it difficult - maybe even impossible to control the airplane - but no amount of wake turbulence can remove the vertical tail at such low flight speeds unless there is a pre-existing structural fault.
What is flutter? This morning, I got an email from a friend who is the Director of Structural Engineering of a major American aircraft maker. He described a chilling picture: "Flutter modes often have an explosively quick onset, rising from nothing to catastrophic in the blink of an eye. Furthermore, the shaking can happen so fast that, despite the large (huge) deflections involved, an observer on the ground might not see it. It's just a blur. The people in the back of the airplane would have been
homogenized back there; but it was all over a few seconds later."
The design weakness can and will be fixed on other Airbuses. If not, there are plenty of nice Boeing jetliners mothballed in the Mojave Desert, that can trade places with the Airbuses. In the meantime, I'm not riding Airbus.
------------------
Brian
