arbj said:I saw a programme on National Geographic (Air crash investigation series) where they showed an aircrash involving a boeing aircraft, the fuselage had developed a large hole (at the top of the aircraft) due to structural failure, an air hostess standing directly underneath was sucked out...in fact she was the only casualty, the body was never found as this happened over the pacific ocean, but the pilot was able to land the plane safely...
So how do you explain the above incident ???...
With pleasure...
arbj,
I have explained briefly the different types of cabin decompression which may occur on an aircraft, but I'll summarize them again to be clear...
Explosive Decompression -
Huge breach in fuselage
Near instant cabin decompression - typically <0.5 sec
High risk of lung damage from sudden deflation of lungs
High risk of occupants or objects being forced from the aircraft
High risk of being struck by flying occupants or objects
High risk of exposure to extremely high wind speeds at minus temperatures
Rapid Decompression -
Moderate breach in fuselage (up to roughly 10" sq)
Fast cabin decompression - typically >0.5 sec
Lower risk of lung damage - decompression slow enough to allow the lungs deflate normally
Low risk of occupants or objects being forced from the aircraft
Moderate risk of being struck by flying objects
Moderate risk of exposure to extremely high wind speeds at minus temperatures
Gradual Decompression -
Small breach in fuselage
Slow cabin decompression - one minute to half an hour depending on altitude
No risk of lung damage
No risk of occupants or objects being forced from the aircraft
No risk of being struck by flying occupants or objects
No risk of exposure to extremely high wind speeds at minus temperatures
High risk of the gradual onset of hypoxia - leading to unconsciousness
I saw that program too and, as per the links (thanks Eric), it was concluded that the structural defects led to a violent and catastrophic explosive decompression, not rapid decompression. With explosive decompression all bets are off as to what the outcome might be.
Geospark said:...Rapid decompression doesn't start sucking people and seats out of the opening Hollywood style!...
What did I mean here?
I didn't mean that rapid decompression could never force an occupant from an aircraft. The Hollywood reference was to where you see a bullet supposedly fired in an aircraft cabin, or even a larger hole, and then you see passengers continuously clinging to a seat headrest with their legs dangling in mid air as though they are continuously being sucked toward the breach. This doesn't happen in reality.
Whether it's rapid or explosive decompression, they typically only last from hundreds of a second to a second or two. The only difference is the velocity at which the cabin decompresses during explosive decompression is much more dangerous for the occupants. Once the pressure in the cabin has equalized with the atmospheric pressure outside the aircraft, the vacuum effect stops. If none of the occupants have been forced from the aircraft during decompression, and all of the occupants now have oxygen masks on, and the pilots are able to maintain flight stability, then the only other dangers to the occupants are the high wind speeds at minus temperatures traveling in and around the cabin. This could blow unrestrained occupants, or objects through or out of the aircraft, or it can cause frostbite or hypothermia. On Aloha Airlines Flight 243, another stewardess was in the aisle unrestrained, but managed to hold on while lying on the floor until the plane landed.
A breach, from a normal split across the rivet holes on the outer skin, should stay confined to the 10" sq sections of ribbing and tear straps, should it give way. This contains the size of the possible breach to an acceptable level where only rapid decompression should occur.
Why did this breach elevate to an explosive decompression level?
The fact that there was a severely compromised outer skin, due to epoxy corrosion and metal fatigue across the rivet holes of several adjacent sections - caused by having been too long in service in a coastal area - the conditions for explosive decompression were created.
arbj said:...an air hostess standing directly underneath was sucked out...
Eric Nelson said:...I suspect the flight attendant may have been blown out, rather than sucked out...
It's actually a matter of perspective...
From inside the cabin she was blown out, from outside the aircraft she was sucked out. For me, I think the general consensus should be to look at it from where we are most likely to be i.e. inside the cabin. So I would prefer to say she was blown, or forced from the aircraft, but I do see a lot of references to occupants having been sucked from an aircraft. Unfortunately for them, blown or sucked, the results are the same.
George