At 35,000 feet in the air and in front of 118 passengers, a gaping five-foot hole opened in the roof of a Southwest Airlines Boeing 737-300 on Friday. Later, "fatigue cracks" caused from 15 years of service were blamed for the terrifying malfunction. But while Southwest is the only airline to ground all its 737-300 aircraft while inspectors search for similar cracks (a search that's turned up three additional damaged planes so far), the other airlines are confident in rolling the dice with their own fleets--and the FAA is fine with letting them do so.
Southwest Airlines has said that the 737-300 model is the oldest in its fleet, 19 years old on average. We haven't crunched the numbers on how old all the other U.S. carriers 737s and other planes are, but relatively recent data published by the FAA says that the average fleet age of Boeing 737-300s is 22 years.
Cracks like the ones found in the Southwest planes are also nothing new. In fact, less than three years ago, Southwest was fined $10.2 million by the FAA for not checking for the exact same kind of fuselage stress fractures blamed for Friday's fiasco.
Despite this, Boeing put out a statement saying it saw no reason to ground 737-300s beyond Southwest's while the fuselages are retested--a conclusion shared by the FAA.
Not that such testing would necessarily find all the cracks. The New York Times reports that the same aircraft that popped open a sunroof on Friday had 21 similar cracks repaired after an inspection in March last year.
But if in two days Southwest has already been able to turn up three other aircraft with gnarly stress cracks in them, one can imagine they'll probably find more.
Why other carriers don't look more closely at their own aircraft--and why the FAA isn't making them--seems risky to the point of foolishness.