Aloha Sunroof 737 Theory
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Aloha Sunroof 737 Theory
The link below is for a site managed by a civil engineer - He has an interesting theory regarding the Aloha incident, that put him at variance with the NTSB. Although the site initially seems unpromising (in name and content) the theory deals with fluid dynamics and SEEMS credible. As an FA I have no technical knowledge whatsoever that is sufficient to comment on the theory, and would therefore be interested to read comments from those that do.
http://www.disastercity.com/ghost/
http://www.disastercity.com/ghost/
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Interesting...
My understanding of what is being proposed is that a large mass of air in the fuselage became sufficiently compressed around teh location of the initial hole and exerted a sufficient force to cause a larger failure...I 'spose it could happen, but it raises a few additional questions:
1.) How much force do you suppose the F/A exerted on the structure when her body momentarily "plugged" the initial hole, compared to the fluid hammer effect that the author is promoting.
2.) I'm under the impression that the 737 (and most other transport aircraft) are designed with tear-straps...circumfrential straps on the fuselage, made of a metal different than the skin. The straps are supposed to be spaced in distances that are shorter than the critical crack length of the skin and prevent a crack in the from growing beyond this length (perhaps the source of 10"x10" figure to which the author refers). I wonder what condition these straps were in after 89,680 cycles and operating in a saltwater environment.
Also, I'm not sure I understand how the analysis of the aircraft's flight recorder data was performed. If this 737 had a regular old analog DFDAU with the Boeing dataframe, the recorded range of the accelerometers is ±1G in the lateral and longitudinal axes and -3G to +6G in the vertical axis with a sampling rate of 8 Hz on all three, which makes it difficult to record some of the values used in the analysis.
Its certainly not my intention to refute any of the evidence proposed, but I'd appreciate any input on the matter.
My understanding of what is being proposed is that a large mass of air in the fuselage became sufficiently compressed around teh location of the initial hole and exerted a sufficient force to cause a larger failure...I 'spose it could happen, but it raises a few additional questions:
1.) How much force do you suppose the F/A exerted on the structure when her body momentarily "plugged" the initial hole, compared to the fluid hammer effect that the author is promoting.
2.) I'm under the impression that the 737 (and most other transport aircraft) are designed with tear-straps...circumfrential straps on the fuselage, made of a metal different than the skin. The straps are supposed to be spaced in distances that are shorter than the critical crack length of the skin and prevent a crack in the from growing beyond this length (perhaps the source of 10"x10" figure to which the author refers). I wonder what condition these straps were in after 89,680 cycles and operating in a saltwater environment.
Also, I'm not sure I understand how the analysis of the aircraft's flight recorder data was performed. If this 737 had a regular old analog DFDAU with the Boeing dataframe, the recorded range of the accelerometers is ±1G in the lateral and longitudinal axes and -3G to +6G in the vertical axis with a sampling rate of 8 Hz on all three, which makes it difficult to record some of the values used in the analysis.
Its certainly not my intention to refute any of the evidence proposed, but I'd appreciate any input on the matter.
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In the book "Air Accident Investigation", by David Owen, this accident is mentioned. The book says that a Japanese passenger, being shorter than other pax, actually saw the crack while boarding. When asked by accident investigators to indicate on another 737 where she saw the crack, she identified the same place as on the accident aircraft.
Who knows, in different circumstances it might all have been different.
Who knows, in different circumstances it might all have been different.
