you know i sat in one of the planes one time when they were doing a pressurization test.
Its amazing that you can actually hear all the crunching metal and popping aluminum - sounds similar to a submarine going deep - during this test.
fact is that this is happening every time the airplane climbs and descends, hundreds of times per week, tens of thousands of times per year for the 15 year lifespan of the airplane in question.
think of the paperclip. bend it a little back and forth, just a little. It will take time to break but it eventually will break.
these airliners are the same way.
sure there are inspections in place to locate cracks and prevent these sorts of failures, and maintenance did in fact find an alarming number of stress cracks in the airframe of this particular aircraft last year.
no matter how rigid and detail oriented your maintenance program may be - these sorts of incidents are not 100% preventable. all you can do is reduce the likelihood of them occurring, but you will never reduce that likelihood to ZERO.
look back at the
dehavilland comet - there were a couple of them IIRC that developed a nasty habit of disintegrating mid flight. the culprit... the window corners had too much pressure buildup during pressurized flight.
the solution: change the windows to a more rounded shape.
the FAA - depending on its findings - may release an Airworthiness Directive on the 737 specifically - which will require periodic inspection of specific places for a specific type of stress fracture, or perhaps they will release some blanket requirement for closer airframe inspections and reduced intervals for aircraft that fly in excess of 1,000 hours per year (1,000 hours is only used as an example number) but at the moment, thats all i would expect to see come of this.
at the moment, the NTSB is of the opinion that nothing was missed on an inspection that should have otherwise been caught.