LarryJ

The result was similar, the cause was not. The problem found on the Yuma airplane was not detectable by the testing that detects the problem from the airplane in 2009.

There is a significant amount of military airspace in that area which flights are routed around.

Because those airplanes are different. I believe that the difference is that the airplanes that aren't currently being inspected were either manufactured with a different technique or have already been re-skinned.

SWABrian

Justin,
the next 100 younger airplanes would be -700s for the most part, and that aircraft is constructed much differently. Having said that, anytime something comes up that we have to inspect, we will inspect it, and then we share our findings with other operators of that aircraft--as we did this time through Boeing and the FAA.

lougord99

Why does rapidity matter?

I am amazed at the responses here. Southwest, along with every other airline in the United States follows maintenance procedures and schedules set out by the experts at Boeing and the FAA. If you have a concern, it is not with Southwest, but with the FAA.

Life_Platinum

[QUOTE=danielonn;16159689]

If US Airways flies the Airbus 319,320 and Continental has the 737-800,737-900s then Southwest needs to start flying the newer 737s and get rid of the 15 year old planes. Its just like an old car which can have so many issues and can pose a safety threat to the driver and passengers. If the FAA was strict they would impose a cutoff on how old a plane is before it retires.

Cutoff on how old a plane is before it retires? What would you suggest? DL has recently retired NW's DC-9s which were 34 years old and some had over 100,000 TT (total time) and 100,000 cycles on them, and when was the last time you heard metal fatigue on a DC-9/MD-80?

ursine1

The FAA sets minimum standards; Southwest (and pretty much every other airline, due to costs involved) chooses to inspect at that level. They could all increase inspections, especially if they know they have an older fleet and -- in Southwest's case -- have a unique business model based on rapid-cycling, which increases risk for metal fatigue. But they don't. When they say "We're doing everything possible to keep our planes safe", what they're really saying is "We're doing everything minimally required to keep the appearance of our planes being safe." Unless they screw up and don't even do that, and then they pay a huge fine, but only after negotiating it down a few million and working out a payment schedule.

I'm thinking the problem is really both the FAA and Southwest; and the relationship that was exposed during the whistleblower / $10M fine saga. I'd have hoped things had changed; it doesn't appear they have.

Some interesting reading:

http://www.thedailybeast.com/blogs-a...ing-fuselages/

http://milesobrien.com/?p=3165

FWAAA

Given that WN found cracks on at least three of the 79 affected 733s, all operators of 737 classics should undertake a nighttime inspection of all 737 classic models. I'm not advocating that they be grounded until inspected (as was the case with these 79 733s) but the entire fleet should be inspected on an expedited basis, not just those in excess of 30k cycles (the FAA's threshhold in the emergency directive on the way).

KelseyR

And they have done just that. FAA has issued an emergency directive to perform the same tests that have been done on WN on the specific early 737 planes.

http://seattletimes.nwsource.com/htm..._boeing05.html

Also:

I just find it really difficult to entirely fault WN when Boeing, the FAA and NTSB also never thought that this incident was possible. Now that they know, all groups are taking the appropriate steps to try to remedy the situation. I know it's an unfortunate situation, but I'm glad that they're working together to re-evaluate their maintenance checks as well.

sctn8gp

... and every bridge you drive over, every building you go in and out of, every whatever you want to come up with- was built by a low bidder to minimum standards set forth in a bidding contract.
it's the way the world goes 'round.....

fireworksboy

Actually the latest tests found the cracks in 3 out of the 19 that tests had been concluded on. Just fyi

pacer142

It is interesting that most of the European low-costs including easyJet and Ryanair fly only brand-new planes (B737-800 for FR, A319/20 for EZY - a few B737-700 left at LTN used for fill-in turns but all will be gone by next year). Is there something different about the US aircraft market?

Neil

Justin026

You are very right and that probability is alarming; I was going to say it that way too but thought it possible that we had 3 out of 19 failing and then the next 60-odd are passing with flying colors. If that is true, that is mostly a good thing -- it would imply that SWA picked the ones most likely to need inspecting out of the pool of 79-81 planes.

But if so, the bad in that is that it could mean SWA quickly knew what to look for with this extra, rapid test they are now doing and suspected how that issue might manifest itself on a very select group of planes.

Other bads would be deciding to read the results more favorably as the tests went along (hmmm, now that we've seen a couple of dozen tests, I think this kind of crack over here can be fixed when this plane is in the shop later on) or the people doing the test changed the methods. Both are tendencies people can have when looking at test data and/or performing repetitive work.

Perhaps an FTer can do the probability of drawing the 3 black beads in a sack with 77 red beads in the first 19 draws.

Justin026

One parallel being discussed here is the use by Northwest of DC-9 aircraft for very long service lives. A dwindling number of these planes came to DL with the merger and are still in service.

The idea that NWA passively followed government or manufacturer recommendations on this group of planes isn't correct. The decisions to extend these planes' lives was made at the corporate level and was managed as a major in-house program. The Atlanta NWA maintenance facility (ex-Southern, ex-Republic) employed over one thousand mechanics for years in the complete refitting and rebuilding of each plane in this program.

This is a far cry from what is happening with SWA and this incident.

InkUnderNails

As someone that does testing of industrial equipment for failure potential, you can always test everything for every potential failure. And, you would always be testing and doing nothing else. You find all of the problems, but you never have the machines in production.

Your second option is to thoroughly test and operate the machine for a while and retest. We can operate for one cycle, one hundred or a million, it does not matter. If the testing shows no failure, the our cycle time is too low for maximum production. But, the arbitrarily chosen cycle time remains. We can actually inspect too much.

The third option, and the one most utilized is to test known failures but try to test inside of the known cycle time. For example, a particular failure is found, usually by discovery during another test but it may be due to an unexpected catastrophic event, that has never been seen before. Immediately a testing procedure is formulated and initiated based on the cycle time in the discovered failure. The new, previously unknown failure process, will now be part of a standard inspection, based on the cycle times determined from the data taken from the newly found failure or the catastrophic event.

This third option has been found to be the optimal in productivity and profitability. It is not however perfectly safe. But nothing is. No complex mechanical process is ever perfectly safe. Commercial aviation is very, very close, but not perfect.

There are other options down the path to the worst option. The worst option, used on a lot of industrial equipment that has little effect on personal safety. Let it run until it breaks. Pick up the pieces and fix it. Run it some more. This is where aviation started.

texashoser

For at least the last couple of years, WN, the FAA, NTSB, and Boeing have all known that the skins on the older, 737 classic series aircraft, especially those with high-cycle life are susceptible to cracking. And they thought a couple of years ago they had a decent program for inspecting to find such cracks before they got bad enough to produce a tear.

We know now that those inspections were only looking for signs of one kind of fatigue and that cracks along the rivet overlap lines can happen now as well. So yet another test is being put together.

The bottom line is that all parties involved know that, quite simply, the skins are wearing out, perhaps faster than everyone thought, and the only real way to permanently solve the problem is either to replace the skins or retire the aircraft. WN, et al, can harp all day long about how they are following the rules, working with the FAA and Boeing, etc, but everyone knows what the solution is - it just costs money. And since the FAA is beholden to the airline industry because the airline industry funds the FAA, the FAA is going to be loathe to force WN (and other US-based operators) to reskin or retire. And since the FAA isn't going to force WN to go this route, you can be sure WN isn't going to do this voluntarily.

EDIT: And what I mean voluntarily is to have the fleet reskinned or retired in short order (like a year), not simply stretch out retirement over 5-10 years, which Brian indicates WN is doing upon taking delivery of new 700-series aircraft.

WN in the mid to late '90's used to have one of the youngest fleets, now they have one of the oldest.

SWABrian

It is different. Northwest made the decision that it could extend the life of the DC-9s (many of which were rebuilt across the runway here at Love Field by the now defunct DalFort Aerospace) in lieu of buying newer aircraft. The equivalent to that would have been Southwest rebuilding our original 737-200s (both from the same timeperiod) and avoiding buying brand new 737-300s or the even newer -700s. We are phasing out the -300s and as we take delivery of a -700, we retire a -300.