Anyone want a 737-200?

737 lap joints used a phenolic shim between the skins. For what I dont know. All they do is accumulate and hold moisture.
Coupled with beer can thin skins and sharp counter sink edges the entire aircraft is a explosive decompression waiting to happen.
But hey; they are light.
Bean counters love the fuel savings.

 

Yeah, those beer can thin skins sure did the job on the lower lobe after the corroded skins were replaced. That fuselage failure had nothing to do with skin thickness or so called phenolic lap joint shims ( where are they located? I've never seen those.) The countersunk rivets on that older 737 had entrapped salt and moisture under them and exposed the alloy to corrosion that was blatantly evident to the naked eye because of the pillowing at the rivet heads. If the 737 fuselage structure had not been properly designed with tear stopper features and dual load paths there WOULD HAVE BEEN explosive decompression instead of a progressive local failure. Before they leave Boeing the airplanes are structurally pressure tested to 12 PSI if my memory serves me.

 

Here is a potential use of this old plane.

http://headlines.verizon.com/headlines/portals/headlines.portal?_nfpb=true&_pageLabel=headlines_portal_page__article&_article=3193412

 

Partial article,

Gangs buy jets for trans-Atlantic coke flights
Associated Press/AP Online


By CHRIS HAWLEY

NEW YORK - Federal investigators are piecing together details of an audacious new trend in drug smuggling: South American gangs are buying old jets, stuffing them full of cocaine and flying them across the Atlantic to feed Europe's growing coke habit.

At least three gangs have struck deals to fly drugs to West Africa and from there to Europe, according to U.S. indictments. One trafficker claimed he already had six aircraft flying. Another said he was managing five airplanes. Because there is no radar coverage over the ocean, big planes can cross the Atlantic virtually undetected.

"The sky's the limit," one Sierra Leone trafficker boasted to a Drug Enforcement Administration informant, according to court documents.

The new air route is remarkable because of the distances involved and the complexity of flying big jets, said Scott Decker, a criminology professor at Arizona State University who studies smuggling methods. A trip from Venezuela to West Africa is about 3,400 miles - about triple the distance to Florida.

The U.N. Office on Drugs and Crime began warning about trans-Atlantic drug planes after Nov. 2, 2009, when a burned-out Boeing 727 was found in the desert in Mali. Drug smugglers had flown the jet from Venezuela, unloaded it and then torched the aircraft, investigators said.

In some cases, executive jets have been used, including a Gulfstream II that landed in Guinea-Bissau in 2008 and another Gulfstream seized in 2007 as it tried to depart Venezuela for Sierra Leone.

In the last year, a flurry of arrests has begun shedding light on how the air routes work. The cases are being prosecuted in a New York federal court because some of the cocaine was supposed to have been sent to the United States.

"The quantity of cocaine distributed and the means employed to distribute it were extraordinary," prosecutors wrote in one case. They warned of a conspiracy to "spread vast quantities of cocaine throughout the world by way of cargo airplanes."

In some ways it is a throwback to the 1970s and '80s, when drug pilots flew freely between Colombia and staging areas near the U.S. border, Decker said. Back then, drug lords such as Amado Carrillo, nicknamed The Lord of the Skies, sent jets with as much as 15 tons of cocaine from Colombia to northern Mexico.

 

Back in the 70s and 80s it was DC-3s, DC-4s (one of which was based in my town back in the 70's), A-20s, B-25s............

 

Looks like a 737 had a rapid decompression today....

http://www.cnn.com/2011/US/04/01/arizona.flight.diverted/index.html?hpt=T1

Some of these airplanes are getting really old and need to be retired...

 

Yes, some of the early 737's are getting old and accumulating too many cycles but they aren't going to explode. It is in their favor that a small piece of skin will pop open without a total structural failure. It's the way they are designed. And before anybody starts talking about the Hawaiian 737 incident, that airplane had a corrosion induced failure, the cause of which went undetected for too long. Even then the lower fuselage held together to save the airplane because it had been reskinned.

 

As a general consensus, if they still have JT8D's hanging off the wings, is that usually an indicator the service operator skimped trying to keep it airworthy?

 

I think it was only 15 years old, not old by airliner standards at all.

 

Not necessarily, just that it is very old.

 

The number of Cycles are far more important than age. How many times the fuselage has been been pressurized and how good was the maintenance are the serious questions. The fuselage structure on that airplane is designed to contain that kind of failure within the distance of the next circumferential frame or within two frames like it did in this case. The tear or crack will not grow to more than 22 inches, that is the frame pitch on that airplane if I remember.

 

That was the flaw in the original de Havilland Comet design. When it suffered decompression, the fuselage skin peeled open like a banana, and total structural failure resulted. Even from the start, Boeing's 707 was designed to prevent that from happening, and it seems to have worked.

 

Yea but in the airline environment they all get **** loads of cycles.

 

2 Pix http://www.nola.com/business/index.ssf/2011/04/fuselage_hole_forces_southwest.html

 

An inspector would have to X-Ray every square foot of the aircraft's skin to detect a crack hidden beneath the paint or primer and even then he most likely would never detect the one that would cause a failure. They most likely will discover some that have already become visible but many times the one that gets you is the one that is undiscovered. That, then, is why we have fail safe fuselage structures in the airplanes that contain failures short of a bomb explosion. The SW Airlines plane was not in danger of falling out of the sky but it is in danger of an uneducated public and a hyped- up press.

 

A phenolic shim?

 

They cover the name of the brand on those beer can skins. Since Phenolic is non-porous I can't see how it can collect any more moisture then steel or aluminum shims. I don't know how many cycles 50,000 hours of flying will break down to but it will be a lot. I'm working on it.

 

Anyone know what series 737 was involved in the event this week? (I can't find it online).

 

It was a 737-300

 

The number of cycles on the Aloha plane was VERY high relative to the number of hours... almost all flights were less than one hour, many in the 30-40 minute range. That was coupled with the salt air environment they fly in; double whammy.

Southwest also has a lot of shorter legs (pressurization cycles) than, say, United or AA.

I don't think total hours are directly translatable to pressure cycles.

 

The number of cycles is what I was trying to "guesstimate" based on an average flight of around 3 hours but my guess was way short at 15000 cycles.