Troubles continue for Boeing’s 737 Max series of airliners, with the latest dangerous incident taking place yesterday above the airport in Portland, Oregon. This was a totally different issue than we’ve seen with these planes in the past and the details are disturbing enough to make it noteworthy, though thankfully nobody was seriously injured. An Alaskan Airlines flight had taken off for its third flight of the day but when it reached 16,000 feet, a window suddenly blew out of the side of the fuselage. The passenger cabin immediately decompressed and the outgassing was so severe that a young boy had his shirt ripped off of him entirely and it blew out of the plane. (Associated Press)

Alaska Airlines grounded all of its Boeing 737-9 aircraft late Friday, hours after a window and piece of fuselage on one such plane blew out in midair and forced an emergency landing in Portland, Oregon. No one was seriously hurt.

The incident occurred shortly after takeoff and the gaping hole caused the cabin to depressurize. Flight data showed the plane climbed to 16,000 feet (4,876 meters) before returning to Portland International Airport. The airline said the plane landed safely with 174 passengers and six crew members.

“Following tonight’s event on Flight 1282, we have decided to take the precautionary step of temporarily grounding our fleet of 65 Boeing 737-9 aircraft.” Alaska Airlines CEO Ben Minicucci said in a statement. “My heart goes out to those who were on this flight – I am so sorry for what you experienced.”

What went wrong here is obvious, but it’s worth noting what went right and how it could have been much worse. 16,000 feet is at least a temporarily survivable altitude for a rapid decompression event. There’s still breathable oxygen at that height, though precious little of it when compared to sea level. It’s also very cold up there. The oxygen masks in the passenger cabin deployed immediately and seemed to function properly. Nobody was sucked out of the plane and the injuries that were treated upon landing were all described as being minor.

Now all of the airline’s planes of that model are grounded and they will begin the process of trying to figure out how this could have happened. This is very different from the lethal issues with the 737 Max class we covered here a few years ago. Those were software problems that made the aircraft unstable while ascending. Boeing didn’t exactly cover itself in glory during the investigation, but it seemed that they finally had everything resolved.

This was a complete and sudden structural failure of the fuselage, not a software glitch. At first glance, it probably makes sense that the windows would be the weakest part of the cabin’s exterior, so if there was going to be a failure of this type that’s where it might happen. But Boeing has been making planes for more than 100 years and I don’t recall hearing about this precise type of failure before. In 1988, Aloha Airlines Flight 243 had a large section of its roof blown off in an explosive decompression event, but it didn’t involve the windows. Sadly, a flight attendant was sucked out of the cabin at 24,000 feet and her body was never recovered. Perhaps interestingly, that plane was also a Boeing 737, but it was a model 200.

These planes are inspected regularly, including x-rays of the fuselage structure. We’ll have to wait for the results of the investigation, but if that fuselage was getting ready to fail, it seems as if the defect could have been detected in advance. Then again, sometimes freak accidents just take place. But it certainly seems like Boeing has more than its fair share. Also, questions have already been raised about their safety standards and transparency in handling investigations. We shall see if anything further comes of this.