When we first learned about the Alaskan Airlines Boeing 737 Max that experienced a “blowout” over Portland, Oregon, questions were immediately raised about how such a failure could have taken place with no warning. The maintenance records of the plane would be under scrutiny and the rest of the fleet of planes was grounded pending the results of the investigation. Now, however, new details have emerged suggesting that this nearly catastrophic failure may not have been entirely “without warning” after all and other disturbing details about the aircraft are being revealed. The original reports indicated that “a window” had blown out of the plane. But in reality, though that section of the skin did have a window in it, an entire unused, sealed doorway had blown out of the aircraft. Even worse, as it turns out, the plane had already been placed on limited duty and was not allowed to fly over the ocean to Hawaii because a warning light related to potential pressurization problems had illuminated on three recent flights. Given that the blowout resulted in a massive depressurization event, shouldn’t the plane have already been grounded for further inspections? (AP)

The Boeing jetliner that suffered an inflight blowout over Oregon was not being used for flights to Hawaii after a warning light that could have indicated a pressurization problem lit up on three different flights, a federal official said Sunday.

Alaska Airlines decided to restrict the aircraft from long flights over water so the plane “could return very quickly to an airport” if the warning light reappeared, said Jennifer Homendy, chair of the National Transportation Safety Board.

Homendy cautioned that the pressurization light might be unrelated to Friday’s incident in which a plug covering an unused exit door blew off the Boeing 737 Max 9 as it cruised about three miles (4.8 kilometers) over Oregon.

Alaskan Airlines obviously has some questions to answer here. If they were so concerned over the warning light that they were limiting the plane’s flight path in case it needed to “return to an airport very quickly,” why were they putting passengers on it to begin with? Also, a warning light blinking on once might turn out to be the result of a failing sensor. But when the same light illuminates on three flights in less than a month (Dec. 7, Jan. 3, and Jan. 4), it seems as if that would have been more than sufficient cause to ground it.

Two of the previous warnings lit up on the two sequential days prior to the failure. The type of warning suggests that pressure may have been leaking out of the seal around the unused door. On the third day, the seal blew entirely. Doesn’t it sound as if the plane was trying to tell them something was amiss?

Other possible defects were exposed during the explosive event. When the cabin depressurized, the cockpit door flew open, banging into a lavatory door. That door is supposed to be sealed to prevent external access by potential terrorists. Yet it was somehow unable to remain closed when the cabin lost pressure. It sounds as if that issue will require further attention as well.

We have further learned that the NTSB will not have the benefit of listening to the pilots’ conversations from the plane’s black box. The system on this model of Boeing aircraft overwrites all recordings after two hours, so those records were not preserved. What is the purpose of such a scrubbing regimen in the current era? Are we to understand that the black box doesn’t have enough storage space to hold recordings more than 120 minutes in length? What do they do about overseas flights that can last for ten hours or more?

As of this morning, nearly all of the Boeing 737 planes of this model used by both Alaskan Airlines and United remain grounded. They are awaiting a technical bulletin from Boeing that will provide specific instruction inspections for the rest of the fleet. From the sound of the details listed above, they will have plenty to inspect. While Alaskan Airlines will likely have to take some responsibility for this event, Boeing seems to have even more questions to answer. The 737 Max 9 has been plagued with issues since it first debuted and the fleet has been grounded multiple times. Thankfully, no one was seriously injured during this blowout, but they need to be able to assure the flying public that there isn’t going to be “a next time.”