Southwest 737 lands at Yeager Airport after hole in fuselage
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....each airline has a list of airports that it considers acceptable alternates (or first choice alternates) and more than anything else has to do with that airline having it's own ops office there so they can handle their own passengers and not have to rely on another airline to do it.
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c'mon guys -
Good old Piedmont airlines flew 737-200's into CRW for many years!
Yeah, you have to be on your game going in there, but that's about it - unless the runway had snow on it.
Metrojet
Good old Piedmont airlines flew 737-200's into CRW for many years!
Yeah, you have to be on your game going in there, but that's about it - unless the runway had snow on it.
Metrojet
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Choosing that airport was a decision they made quickly. If it was legal for them to land there they were correct in landing there. We can second guess all we want but when you are dealing with an emergency you have to have a plan and they had one. They were legal and safe.
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Originally Posted by vapilot2004
For aircraft fatigue, age is not the primary issue. Cycles are.
I was mistakenly under the impression that N73711 (at the time the second-highest cycle 737 airframe in the world) only let go after considerably longer.
J.
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Bonger
Bingo!
"scoring or scribe lines"
Today Show video
Now comes the real question. Why is Southwest still flying these planes if they know about the "scoring or scribe lines"???????????
"scoring or scribe lines"
Today Show video
Now comes the real question. Why is Southwest still flying these planes if they know about the "scoring or scribe lines"???????????
An aircraft can quite safely fly with with a score or scribe line and most already do. Any score, scribe, crack, dent, ding or corrosion discovered in day to day operation or even maintenance should / will be cleaned up, measured and assessed against published limits (Structural Repair Manual, SB, AD, etc.). If inside these limits an inspection program and "repair by" limit is then set or it may even just be reprotected and recorded.
If it is outside published limits then you carry out the repair specified or you can go to the TC holder and ask if repair can be deferred to a more suitable time or if there is an interim repair with full repair at a later date. The TC holder may come back with some immediate repair actions, an inspection program and final fix date, or they come back with a "repair before next flight".
The AD mentioned, if I am thinking of the same one, is looking for scoring or chafing of the fuselage skin where the (removable) dorsal fin that runs forward of the vertical stab caused by the dorsal fin vibrating where comes into contact with the skin. The location of the hole in this aircraft is forward of the area the AD applies to. Red herring.
The reporter says 11 cracks were found on the aircraft during maintenance last year. A bit of sensationalism going on there. That's no big deal - that's why you have a maintenance program and inspectors. For an aircraft that age and if it is high cycles then 11 is pretty good, perhaps even on the low side. Whoops, set things up now for the "poor maintenance" nay-sayers.
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Capital Airlines in either late 1950s or early 1960s lost two airplanes in the same day - a Viscount near BAL, and a Connie at CRW, off the end of the RWY.
The thing that surprised me the most about CRW was on a run downtown and there on the river was a huge Coast Guard cutter. It had come up from the Gulf on the Mississippi and then the Ohio. I think I have my geography right but the rivers are navigable all the way to Pittsburgh. ??
The Capital Connie went down the hill backwards.
Charleston, WV Air Liner Slides Off Runway, May 1959 | GenDisasters ... Genealogy in Tragedy, Disasters, Fires, Floods
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Sonic Bam, it seems that at the location of the hole, there is an antenna on some aircraft. In that particular case, the antenna is used for ELT.
Do you know is there is any structural provision for antenna installation on B737 ? (or repair, or plug due to antenna removal on this acft ?)
Edit : well, disregard this message
Do you know is there is any structural provision for antenna installation on B737 ? (or repair, or plug due to antenna removal on this acft ?)
Edit : well, disregard this message
Last edited by Domi; 16th Jul 2009 at 22:39.
Psychophysiological entity
As soon as the skipper realized that there was structural damage, he may well have felt that it was a good idea to get his charge on the ground. Seems reasonable.
I would have been loathe to send anyone back there to brief me on the damage, or indeed have anyone unstrapped, so One would have had to assume that it was serious.
However, the counter argument might be that knowing the integrity of the hull was compromised, he should then treat the aircraft like glass, and get - 45NM? - to a less demanding field, reasoning that any vigorous control movements might just possibly exacerbate the structural problem.
His call.
I would have been loathe to send anyone back there to brief me on the damage, or indeed have anyone unstrapped, so One would have had to assume that it was serious.
However, the counter argument might be that knowing the integrity of the hull was compromised, he should then treat the aircraft like glass, and get - 45NM? - to a less demanding field, reasoning that any vigorous control movements might just possibly exacerbate the structural problem.
His call.
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Join the dots
This might be why they're looking at scribe lines;
http://www.ntsb.gov/Pressrel/2009/SW-737-interior.jpg
http://www.ntsb.gov/Pressrel/2009/SW-737-exterior.jpg
Rgds.
24V
http://www.ntsb.gov/Pressrel/2009/SW-737-interior.jpg
http://www.ntsb.gov/Pressrel/2009/SW-737-exterior.jpg
Rgds.
24V
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I really think that
my original comment about selecting CRW as an emergency airport was meant to make people think.
think twice about where you go...you may take a near disaster and turn it into a full fledged disaster.
I've landed the DC9 at CRW many times. In all weather. No one I ever flew with was casual about a landing or takeoff from this airport. We planted it and got into reverse pronto...but using brakes as needed...you see if you were on a quick turn and your brakes were hot, you might sacrifice abort performance on a quick takeoff.
There are many things a really good pilot should be considering at all times.
KPIT is about 140 miles from CRW...about 20 minutes more flying time...I might have gone there...better runways, better CFR, some of the best hospitals in the world, and perhaps most importantly...BETTER PIZZA in the vicinity of the airport (kidding). Time critical...sure go to CRW...or even HTS.
With structural failure, I might have done a slower descent too!
and Wiley...the rivers of america are amazing. I've seen big ships there just as you have. Heck, aircraft carriers have gone to chicago for gosh's sake!~
so again, good job to the crew...but now we are just talking, thinking about ''what if'' for our own use in the future.
If I thought a plane was coming apart, I wouldn't hesitate to land on a stretch of interstate...it is said that every 50 miles along the interstate, there is at least a 5000' straight patch that could serve as a runway.
Indeed, many european nations have plans to use their freeways/autobahns as runways during war emergency.
think twice about where you go...you may take a near disaster and turn it into a full fledged disaster.
I've landed the DC9 at CRW many times. In all weather. No one I ever flew with was casual about a landing or takeoff from this airport. We planted it and got into reverse pronto...but using brakes as needed...you see if you were on a quick turn and your brakes were hot, you might sacrifice abort performance on a quick takeoff.
There are many things a really good pilot should be considering at all times.
KPIT is about 140 miles from CRW...about 20 minutes more flying time...I might have gone there...better runways, better CFR, some of the best hospitals in the world, and perhaps most importantly...BETTER PIZZA in the vicinity of the airport (kidding). Time critical...sure go to CRW...or even HTS.
With structural failure, I might have done a slower descent too!
and Wiley...the rivers of america are amazing. I've seen big ships there just as you have. Heck, aircraft carriers have gone to chicago for gosh's sake!~
so again, good job to the crew...but now we are just talking, thinking about ''what if'' for our own use in the future.
If I thought a plane was coming apart, I wouldn't hesitate to land on a stretch of interstate...it is said that every 50 miles along the interstate, there is at least a 5000' straight patch that could serve as a runway.
Indeed, many european nations have plans to use their freeways/autobahns as runways during war emergency.
Just guessing - but looking at the shape of the tear and the way it follows the backing plate profile - I'd be looking for a pencil line or some graphite trace on the inner face of the torn skin.
Rigga
Rigga
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Pres release that accompanied the photos posted above by 24victor:
************************************************************
NTSB ADVISORY
************************************************************
National Transportation Safety Board
Washington, DC 20594
July 16, 2009
************************************************************
NTSB RELEASES PHOTOS OF DAMAGED SECTION OF SOUTHWEST
AIRLINES 737 FUSELAGE
************************************************************
In its continuing investigation of the Southwest Airlines
737-300 (N387SW) that experienced a rapid decompression
during a flight from Nashville to Baltimore on July 13,
2009, NTSB Acting Chairman Mark V. Rosenker has authorized
the release of two photographs showing the compromised
section of the area of the fuselage that failed in flight.
The damaged aircraft skin section was visually examined in
the NTSB's Materials Laboratory. The damage left a hole
measuring approximately 17 inches by 8 inches. The skin in
this area of the fuselage is 0.032 inches thick with an
additional 0.032 inch thick layer bonded to the interior
surface in selected areas.
Rosenker said that the initial visual examination found the
fractures in good condition and suitable for further
analysis. No significant corrosion or obvious pre-existing
mechanical damage was noted. A detailed metallurgical
examination of the skin section and the fracture surfaces
will be accomplished by the Safety Board in the coming days.
Southwest Airlines is now in the process of repairing the
aircraft at Yeager Airport, Charleston, West Virginia.
Section of fuselage skin facing inside the aircraft:
http://www.ntsb.gov/Pressrel/2009/SW-737-interior.jpg
Section of fuselage skin on exterior of aircraft
http://www.ntsb.gov/Pressrel/2009/SW-737-exterior.jpg
###
Media Contact: Peter Knudson
[email protected]
(202) 314-6100
************************************************************
This message is delivered to you as a free service from the
National Transportation Safety Board.
You may unsubscribe at any time at
NTSB - Mailing Lists
An archive of press releases is available at
NTSB - Press Releases
Current job opportunities with the NTSB are listed at
NTSB - Vacancy Announcements
For questions/problems, contact [email protected]
************************************************************
NTSB ADVISORY
************************************************************
National Transportation Safety Board
Washington, DC 20594
July 16, 2009
************************************************************
NTSB RELEASES PHOTOS OF DAMAGED SECTION OF SOUTHWEST
AIRLINES 737 FUSELAGE
************************************************************
In its continuing investigation of the Southwest Airlines
737-300 (N387SW) that experienced a rapid decompression
during a flight from Nashville to Baltimore on July 13,
2009, NTSB Acting Chairman Mark V. Rosenker has authorized
the release of two photographs showing the compromised
section of the area of the fuselage that failed in flight.
The damaged aircraft skin section was visually examined in
the NTSB's Materials Laboratory. The damage left a hole
measuring approximately 17 inches by 8 inches. The skin in
this area of the fuselage is 0.032 inches thick with an
additional 0.032 inch thick layer bonded to the interior
surface in selected areas.
Rosenker said that the initial visual examination found the
fractures in good condition and suitable for further
analysis. No significant corrosion or obvious pre-existing
mechanical damage was noted. A detailed metallurgical
examination of the skin section and the fracture surfaces
will be accomplished by the Safety Board in the coming days.
Southwest Airlines is now in the process of repairing the
aircraft at Yeager Airport, Charleston, West Virginia.
Section of fuselage skin facing inside the aircraft:
http://www.ntsb.gov/Pressrel/2009/SW-737-interior.jpg
Section of fuselage skin on exterior of aircraft
http://www.ntsb.gov/Pressrel/2009/SW-737-exterior.jpg
###
Media Contact: Peter Knudson
[email protected]
(202) 314-6100
************************************************************
This message is delivered to you as a free service from the
National Transportation Safety Board.
You may unsubscribe at any time at
NTSB - Mailing Lists
An archive of press releases is available at
NTSB - Press Releases
Current job opportunities with the NTSB are listed at
NTSB - Vacancy Announcements
For questions/problems, contact [email protected]
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Humble Pie Being Consumed
Wow, I stand corrected, that doesn't look like fatigue cracking to me. Somebody is in the cack.
I'll be off to mind my own business now.
I'll be off to mind my own business now.
Last edited by Sonic Bam; 17th Jul 2009 at 15:05.
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Fatigue
The thing with fatigue is that it starts with grain growth in the metal. When you see the crack, you are already far down the road to failure, because of the intense stress concentration at the knife-edged leading point of the growing crack. Visible cracks increase rapidly in length.
A paper here yesterday published a picture looking back at the tail fin. What I think to be a major factor leapt right out at me. The fin is a double airfoil. In the area of the failure, the passing air is speeding up (and thus dropping in pressure) to pass the fin. I think you'll realize that you can't have pressure at a single point that is different in two directions.
Thus locally there is a drop in pressure on the hull at right angles to this surface that failed. That is, here the pressure differential at altitude is greater that the pressure used in the fatigue life test. Fatigue is very sensitive to the pressure range, moreso that to the actual level of stress.
Fatigue life testing is (or was) done by filling a hull with water, and pressurizing the water. Rapid cycles, and no danger of flying fragments. However, the pressure applied is perfectly uniform.
Now as for the panel-like appearance of the pop-out, when you have a dome-like deformation under pressure, the stresses at the restrained perimeter edges of the dome will be something like twice the stress in the center of the dome. This is very counter-intuitive but it is so.
The rip-stoppers are the restraint, although they are somewhat yielding. That and their rectangular pattern make for a situation that is very difficult to analyze, either by math or by models such as plastics that can show visible stress patterns in special lighting. Well, I may be showing my age by mentioning such ancient methods.
NTSB will of course etch the edges of the break and make a microscopic inspection for grain growth (compared to an as rolled sample of the material). I think you will see this will show fatigue damage was present.
Back to runway length-- I apologize for just throwing out "minimum" length. I should have said "minimum design standard", which is a hole-in-the-cheese eliminator approach. An operational minimum is entirely different, of course. I'll explain why as soon as I have time. Washington National was the classic example, as FAA HQ was on this field for many years.
OE
On reflection, I realized I should not leave the impression that this (local pressure reduction) is an unrecognized problem. Crown inspections seem to me to indicate an awareness there is some problem which must be guarded against.
A paper here yesterday published a picture looking back at the tail fin. What I think to be a major factor leapt right out at me. The fin is a double airfoil. In the area of the failure, the passing air is speeding up (and thus dropping in pressure) to pass the fin. I think you'll realize that you can't have pressure at a single point that is different in two directions.
Thus locally there is a drop in pressure on the hull at right angles to this surface that failed. That is, here the pressure differential at altitude is greater that the pressure used in the fatigue life test. Fatigue is very sensitive to the pressure range, moreso that to the actual level of stress.
Fatigue life testing is (or was) done by filling a hull with water, and pressurizing the water. Rapid cycles, and no danger of flying fragments. However, the pressure applied is perfectly uniform.
Now as for the panel-like appearance of the pop-out, when you have a dome-like deformation under pressure, the stresses at the restrained perimeter edges of the dome will be something like twice the stress in the center of the dome. This is very counter-intuitive but it is so.
The rip-stoppers are the restraint, although they are somewhat yielding. That and their rectangular pattern make for a situation that is very difficult to analyze, either by math or by models such as plastics that can show visible stress patterns in special lighting. Well, I may be showing my age by mentioning such ancient methods.
NTSB will of course etch the edges of the break and make a microscopic inspection for grain growth (compared to an as rolled sample of the material). I think you will see this will show fatigue damage was present.
Back to runway length-- I apologize for just throwing out "minimum" length. I should have said "minimum design standard", which is a hole-in-the-cheese eliminator approach. An operational minimum is entirely different, of course. I'll explain why as soon as I have time. Washington National was the classic example, as FAA HQ was on this field for many years.
OE
On reflection, I realized I should not leave the impression that this (local pressure reduction) is an unrecognized problem. Crown inspections seem to me to indicate an awareness there is some problem which must be guarded against.
Last edited by Old Engineer; 17th Jul 2009 at 12:43. Reason: Added comment re crown inspections
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The skin in this area of the fuselage is 0.032 inches thick with an
additional 0.032 inch thick layer bonded to the interior
surface in selected areas.
additional 0.032 inch thick layer bonded to the interior
surface in selected areas.
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Quote: The skin in this area of the fuselage is 0.032 inches thick with an additional 0.032 inch thick layer bonded to the interior surface in selected areas. ---- Is that the 2 layers we see in the NTSB images, the skin and the interior layer? It looks like what I see when I open the inner seal on a bottle of vitamin pills.
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Cheers!
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Skin deep
That's 30 times heavier than the good Reynold's Wrap and nearly triple (within 1/1000th of an inch) the average thickness of what protects one from the contents of the average can of Coca Cola.
Rgds.
24V
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Very Helpfull
Thus locally there is a drop in pressure on the hull at right angles to this surface that failed. That is, here the pressure differential at altitude is greater that the pressure used in the fatigue life test. Fatigue is very sensitive to the pressure range, moreso that to the actual level of stress.
An Extremely informative post, Old Eng.
Would oil canning be an early indication of weakness in this area of dome shaped stress concentration ? I would imagine joggled rivets could be another but then it depends on the stage of failure with ref to the Insp date.
As a Airframe Inspector i have to carry out crown skin inspections but have never come across ref material indicating the possibility of a localised diff pr causing the scenario you describe.
Cheers.
