Has there ever been a better way to avoid work that reciting this bromide? It sounds like real common-sense homey wisdom, comes trippingly off the tongue, and raises the fear of all the things that could go wrong if we go turning over rocks and stirring things up.
Look how well it’s working for Southwest Airlines, after all. Nobody died when the one plane came unstitched, and all the others were racking up revenue miles; what’s not to like?
If it ain’t broke, it may never have worked in the first place.
This seems unfair. Southwest has a really good safety record.
What we’re doing with our jetliners is a daily experiment. No one knows how long these planes can actually fly. Compare military jets: we haven’t built a B-52 since 1962, and the Air Force expects to keep them flying into the 2040s. The longer all these planes fly, the more we discover ways they can go wrong. I don’t understand why Southwest should be singled out here.
My personal philosophy starts with “If it ain’t broke, don’t fix it.” However, it doesn’t end there. It goes on with two more points: “If you can’t fix it, don’t break it,” and finally “Just because it works doesn’t mean it ain’t broke.”
And I’m sort of with Anderson here. This may change as more information comes out, but from what I’ve read so far, it’s not clear that Southwest really should have done anything better. Except in very specific hindsight that would have qualified as precognition before last Friday.
Anderson: There’s a really well-thought-out (if not perfectly implemented) regime for inspecting aircraft. All the structural people in sight do extensive analysis (backed up with ongoing data) to ensure that any crack or other flaw would have to be developing for at least two inspection intervals before getting big enough to cause a failure. (Yeah, there are other criteria as well.) People have been watching cracks propagate around aircraft rivets for upwards of 60 years now, so the process is pretty well understood. Initial reports say the the whole area around the break contained pre-existing cracks. So either the inspection of hard-to-reach areas was not as thorough as the rules specify, or almost everything we know about metal fatigue in aircraft is wrong.
Paul, I dunno, I’m not an expert (or a Southwest shill), but an easy Google hit yields this:
In a media briefing Monday in Yuma, Ariz., where the damaged airplane made an emergency landing Friday, NTSB board member Robert Sumwalt said both Boeing and the FAA “have not believed that this particular lap joint on this model airplane was one that warranted attention on an aircraft with this amount of takeoffs and landings.”
“It was not believed that this was an area that could fail, until we see it now,” Sumwalt said.
So it doesn’t seem too surprising that no one checked the area in question. Maybe now planes will be subjected to periodic whole-fuselage tests with the electromagnetic tool mentioned at the link. But evidently that wasn’t anyone’s policy beforehand. I am happy to be shown otherwise, of course.
Anderson: It’s unusual for NSTB people to say something so clear at such an early stage, but you’re right. The public statements, at least, suggest that something, uh, interesting, is happening. (It also suggests that, as has sometimes happened in the past, the FAA and the airlines have been taking a head-in-the-sand approach assuming that newly-discovered problems are as narrow as the data can be construed to permit. Which also makes the engineers’ and modelers’ job harder.)
I believe in the adage of not fixing things that aren’t broken, but a fuselage with stress fractures IS broken.