Yesterday afternoon, a 737-300 (N387SW) operating as Southwest 2294 made a safe emergency landing at Yeager Airport near Charleston, West Virgina after depressurizing due to an apparent hole in the upper fuselage of the aircraft.
The incident has caused Southwest to inspect its 737-300 fleet, and according to the Seattle Post Intelligencer, Boeing is sending personnel to provide technical assistance to the NTSB.
The incident has caused Southwest to inspect its 737-300 fleet, and according to the Seattle Post Intelligencer, Boeing is sending personnel to provide technical assistance to the NTSB.
on July 14, 2009 4:07 PM | Reply
Looks to me, like some of the statements "Blows hole in fuselage" or as seen elsewhere :rips open like a tin can" are a litle overwrought, (unless you had to experience the decompression and emergency descent).
There probably is (was)an ADF antenna right in that spot. In interior photos of the aircraft, you can just about see the flange around the port (Hole) in the fuselage where it normally rests.
So lets make this a technical question, not one of advanced hyperbole ok? Looking like loose or failed fasteners no? Not a problem with the pressure hull itself.
on July 14, 2009 4:45 PM | Reply
Jon regarding the clip for the coming movie,"From Earth to the Moon";who came up with the notion that all aerospace engineers wear white shirts with a tie and pocket protector should be shot!
on July 15, 2009 6:10 PM | Reply
It seems to me that the airframe behaved exactly as designed in case of hull fracture- to tear off a 12" square in a controlled fashion as opposed to an uncontrolled fracture that could lead to airframe loss.
Am I missing something?
on July 17, 2009 9:26 AM | Reply
We now have close up photos of the portion of the skin after it was excised and handed over to the FAA:
http://www.ntsb.gov/Pressrel/2009/SW-737-interior.jpg
http://www.ntsb.gov/Pressrel/2009/SW-737-exterior.jpg
Explanation:
Boeing's skins are not of uniform thickness. They are full thickness under stringers, shear ties, around laps and splices, but are milled to a reduced thickness in other empty areas to save weight.
This is one of those areas.
You can see in the interior photo two rows of rivet holes. These are the positions of the stingers or stiffeners as rivited to the skins.
Puzzeling is the absence of traces of sealant where the stringers were (it should be there), but this may have remained on the underlying structure....but no signs of sealant is still disturbing. All attachments to the skin are to be sealed for corrosion protection, and I see nary a shadow. Maybe just a trace at either end...
Be that as it may, there are no obvious signs of corrosion. The brown goo all over is corrosion inhibitor.
So, hazarding speculation, it's quite possible that the skin was milled to thin at this spot. The failure mostly follows the milled edge. And was checked by it.
The other possibility is that an assembler used a sharp tool to clean chips out from behind the stringer during the build, and scored the skin in one spot, setting up a stress riser that eventually fatigued into a crack.
One other possibility comes to mind....
the stringer or stiffener was gapped to the skin. This improper assembly might explain the lack of sealant on the skin surface. Such a gapped installation might allow flex and accelerated fatigue.