AA B757 Exp. Decompression, FL310 due 1' x 2' hole in fuselage
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Fluid Hammer
Willit Run
Aloha Air flight 293
If I remember correctly, a member of the crew was "sucked" towards a small hole in the fuselage, blocked it, then the 'fluid hammer' effect basically destroyed a good part of the fuselage. Explosive decompression, but aircraft landed safely.
Cheers
Ros
Air is compressible, so no hammer effect like hydraulics.
If I remember correctly, a member of the crew was "sucked" towards a small hole in the fuselage, blocked it, then the 'fluid hammer' effect basically destroyed a good part of the fuselage. Explosive decompression, but aircraft landed safely.
Cheers
Ros
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Just for the sake of verisimilitude... Talk of 'explosive' decompression is probably inaccurate in this case... 'Rapid' decompression is more likely to be the appropriate term.. If I remember correctly, explosive decompression refers to a total decompression within 1/2 second, this would more likely be the result of a door blowing off, a bomb or a huge structural failure similar to that of the 747 a few years back where passengers were sucked out of the aicraft through a hole you could have driven a volkswagen through... the instant loss of compression often proves fatal to some passengers as lungs and other organs are unable to adapt quickly enough.
Rapid decompression I think is between 1/2 and 1 1/2 seconds... as there were no injuries reported this was the more likely time scale the incident falls into.... or an even slower category...I stand to be corrected.. I'm no expert.
Rapid decompression I think is between 1/2 and 1 1/2 seconds... as there were no injuries reported this was the more likely time scale the incident falls into.... or an even slower category...I stand to be corrected.. I'm no expert.
Last edited by MungoP; 29th Oct 2010 at 03:10. Reason: sp
Aloha Air 243, actually.
The "fluid hammer" effect was suggested as a factor in that accident by an engineer, but not accepted by the NTSB in its final report - which found that widespread fatigue due to a very high number of cycles sufficiently accounted for 1/3 of the cabin skin "unzipping" following the initial failure. http://www.jethag.com/wp-content/upl...009/10/243.jpg
But an FA was, indeed, sucked out during the decompression, the sole fatality.
The incident MungoP refers to was United Flight 811: http://www.warman.demon.co.uk/anna/united.jpg - due to an age (but not fatigue) induced cargo-door locking failure.
The "fluid hammer" effect was suggested as a factor in that accident by an engineer, but not accepted by the NTSB in its final report - which found that widespread fatigue due to a very high number of cycles sufficiently accounted for 1/3 of the cabin skin "unzipping" following the initial failure. http://www.jethag.com/wp-content/upl...009/10/243.jpg
But an FA was, indeed, sucked out during the decompression, the sole fatality.
The incident MungoP refers to was United Flight 811: http://www.warman.demon.co.uk/anna/united.jpg - due to an age (but not fatigue) induced cargo-door locking failure.
Last edited by pattern_is_full; 29th Oct 2010 at 03:31.
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Just another chem milled stress failure says Boeing >>>
"Boeing finite element modeling suggests stress levels are higher in the skin at the edges of chemically milled steps adjacent to non-chemically milled bays due to the difference in stiffness.”
See NTSB's Accident/Incident reports for that earlier Southwest 'skylight' at Link > DCA09FA065
Cause > "Fuselage skin failure due to preexisting fatigue at a chemically milled step".
and a good article with more overview at Link >Metal Fatigue Led to Fuselage Rupture|Aviation Safety Journal
Looks like the easier exterior inspections may now be a problem. Inside inspections are a lot more work.(ceiling, ducts, insulation).
"Boeing finite element modeling suggests stress levels are higher in the skin at the edges of chemically milled steps adjacent to non-chemically milled bays due to the difference in stiffness.”
See NTSB's Accident/Incident reports for that earlier Southwest 'skylight' at Link > DCA09FA065
Cause > "Fuselage skin failure due to preexisting fatigue at a chemically milled step".
and a good article with more overview at Link >Metal Fatigue Led to Fuselage Rupture|Aviation Safety Journal
Looks like the easier exterior inspections may now be a problem. Inside inspections are a lot more work.(ceiling, ducts, insulation).
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2W2R writes,
Yes, no doubt Americans are needing cargo doors for boarding these days, but had the unfortunate flight been a Charter of German or English tourists, would be about the same situation. 
As it was an AA flight I doubt any American will be brave enough to suggest they could fit through a 1ft x 2ft hole, last AA flight I was on many of them on board were lucky to get through the bloody door!!!
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2 Whites 2 Reds, if you don't think a 1' X 2' opening isn't large enough for a passenger to fit through, how do you explain this from airsafe.com:
3 November 1973; National Airlines DC10; over New Mexico, USA: The aircraft had an uncontained failure of one of the wing mounted engines. A piece of the engine struck the fuselage and broke a passenger window. One of the 116 passengers was sucked out of the aircraft during a rapid decompression. The remains of the passenger were not found.
By the way the DC-10 window is 10" X 16".
3 November 1973; National Airlines DC10; over New Mexico, USA: The aircraft had an uncontained failure of one of the wing mounted engines. A piece of the engine struck the fuselage and broke a passenger window. One of the 116 passengers was sucked out of the aircraft during a rapid decompression. The remains of the passenger were not found.
By the way the DC-10 window is 10" X 16".
Last edited by glhcarl; 29th Oct 2010 at 20:53.
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It's companion ship the 767 is a wide-body
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That second related incident
Some have asked for some detail to that second fuselage incident being investigated by the NTSB.
First from that American story >
Source; Officials investigate what caused hole in American jet's fuselage | News for Dallas, Texas | Dallas Morning News | Airlines | Dallas Business News
Quote >
The NTSB is looking at similar damage discovered on a United Airlines plane on Sept. 11, Holloway said. NTSB and Federal Aviation Administration officials said they had not yet conducted broader safety checks of Boeing 757s. End --- see Link above for full text story.
Discussion. In spite of the NTSB’s claim to a September 11 United incident, there is no NTSB record at the NTSB’s Accident/Incident database as of October 29,2010. See NTSB Link > N T S B - Sep 2010 Aviation Accidents by date
Records search of SDR database for September 11 United fuselage incident Sept 9-12th. Results 51 records. Two records found below for the 10th and Reg 509UA for a dent and 520UA for ‘over a 10 inch crack’. The latter is a severe damage and likely to be the one the NTSB would be looking at. See Below >
Partial texts, See bottom on how to retrieve the full text reports
UALA2010091303389 9/10/10. 757. Reg 509UA. 520UA. JASC/ATA Code 5330. Problem Description; Ext fuselage at BS 418, between STR. 19 and 20l is dented. Major repair accomplished: found dent to be out of limits.
UALA2010091303386 9/10/10. JASC/ATA Code 5330. Problem Description; Fuselage crack on upper crown area. Crack measures 10.75 inches. Located at sta(tion) 426 stringer S4l and above first pax (passenger) window Lt (left)side.
Frivolous Filings. 60 % are spam mail.
In addition and amongst the 51 records were 23 records for code 3350 and 8 records for code 3397. Both codes are for ground replacements of lights and are not required reporting to the FAA but they do serve to ‘pump up’ the numbers and the appearance of compliance. 60 % of the 51 records here (sum of 23 +8) and are typical of the industry - wide practice filings of frivolous filings seen in another one year survey of nine carriers. Quantity does not mean quality.
How to retrieve full text SDR reports.
FAA’s Service Difficulty database and query search;
Link > FAA :: SDR Reporting [Service Difficulty Report Query Page]
To access SDRs seen here, merely enter the ‘Control Number’ (i.e. UALA2010091303389) into that data field , press “Run Query”.
First from that American story >
Source; Officials investigate what caused hole in American jet's fuselage | News for Dallas, Texas | Dallas Morning News | Airlines | Dallas Business News
Quote >
The NTSB is looking at similar damage discovered on a United Airlines plane on Sept. 11, Holloway said. NTSB and Federal Aviation Administration officials said they had not yet conducted broader safety checks of Boeing 757s. End --- see Link above for full text story.
Discussion. In spite of the NTSB’s claim to a September 11 United incident, there is no NTSB record at the NTSB’s Accident/Incident database as of October 29,2010. See NTSB Link > N T S B - Sep 2010 Aviation Accidents by date
Records search of SDR database for September 11 United fuselage incident Sept 9-12th. Results 51 records. Two records found below for the 10th and Reg 509UA for a dent and 520UA for ‘over a 10 inch crack’. The latter is a severe damage and likely to be the one the NTSB would be looking at. See Below >
Partial texts, See bottom on how to retrieve the full text reports
UALA2010091303389 9/10/10. 757. Reg 509UA. 520UA. JASC/ATA Code 5330. Problem Description; Ext fuselage at BS 418, between STR. 19 and 20l is dented. Major repair accomplished: found dent to be out of limits.
UALA2010091303386 9/10/10. JASC/ATA Code 5330. Problem Description; Fuselage crack on upper crown area. Crack measures 10.75 inches. Located at sta(tion) 426 stringer S4l and above first pax (passenger) window Lt (left)side.
Frivolous Filings. 60 % are spam mail.
In addition and amongst the 51 records were 23 records for code 3350 and 8 records for code 3397. Both codes are for ground replacements of lights and are not required reporting to the FAA but they do serve to ‘pump up’ the numbers and the appearance of compliance. 60 % of the 51 records here (sum of 23 +8) and are typical of the industry - wide practice filings of frivolous filings seen in another one year survey of nine carriers. Quantity does not mean quality.
How to retrieve full text SDR reports.
FAA’s Service Difficulty database and query search;
Link > FAA :: SDR Reporting [Service Difficulty Report Query Page]
To access SDRs seen here, merely enter the ‘Control Number’ (i.e. UALA2010091303389) into that data field , press “Run Query”.
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To be really picky, the A380 isnt a widebody either...its just a twin aisle jet with 4 extra seats per row....... 
I mean where does it end.....
I mean where does it end.....
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More Pictures
Here are more initial pictures of the damage immediately after the incident:
http://img5.imagesha...g=imag0188x.jpg
And here are pictures after the repair began indicating and extended area of potential skin failure.
http://img5.imagesha...g=imag0188x.jpg
Edited to add, I’m no aircraft engineer but I read on another forum that this level of the fuselage is an area where the thickness of the aluminum skin is milled down to (to reduce weight?), It was noted that there is no visual evidence of corrosion and no jagged edges. There is speculation that a thickness check may indicate a variance with the specs. If so, I would bet it will precipitate further checks on other Boeing aircraft with aluminum from the same milling batch. I’m sure Boeing has the records.
http://img5.imagesha...g=imag0188x.jpg
And here are pictures after the repair began indicating and extended area of potential skin failure.
http://img5.imagesha...g=imag0188x.jpg
Edited to add, I’m no aircraft engineer but I read on another forum that this level of the fuselage is an area where the thickness of the aluminum skin is milled down to (to reduce weight?), It was noted that there is no visual evidence of corrosion and no jagged edges. There is speculation that a thickness check may indicate a variance with the specs. If so, I would bet it will precipitate further checks on other Boeing aircraft with aluminum from the same milling batch. I’m sure Boeing has the records.
Last edited by kappa; 30th Oct 2010 at 02:32.
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Talk of 'explosive' decompression is probably inaccurate in this case... 'Rapid' decompression is more likely to be the appropriate term.. If I remember correctly, explosive decompression refers to a total decompression within 1/2 second
None the less lives were in danger at the hands of the crew.
Last edited by grounded27; 30th Oct 2010 at 04:45.
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BRE:
According to the WSJ, the incident aircraft had less then 25,000 hours:
American Jet Suffered Two-Foot Hole, Cabin Decompression - WSJ.com
60,000 hours will probably make it one of the oldest jets in legacy service not that NWA have retired their DC-9?
American Jet Suffered Two-Foot Hole, Cabin Decompression - WSJ.com