The National Transportation Safety Board provided another update Monday night on its investigation into the Alaska Airlines flight which lost a door panel mid-flight last week.
Those officials said an examination of a panel that blew out of the Boeing 737 Max 9 last Friday showed signs of fractured guides and missing bolts, though it is possible the fasteners were lost when the so-called door plug was expelled.
NTSB engineer Clint Crookshanks said that it appears the door plug moved upward, then out during the explosive decompression — which happened as Alaska Flight 1282 was 10 minutes into its flight from Portland to Ontario, CA.
The door plug is held in place, in part, by 12 stop pads designed to prevent it from being blown upward. But, in this case, it appeared to slip upwards and around the pads.
“What we don’t understand yet is why the door moved up,” said retired airline Captain Douglas Rice.
He said the panel usually moves up in order to do maintenance on the plane, which wasn’t the case during the mid-flight incident.
“The key is what is it that keeps this door from moving in a vertical direction, whether it's the bolts or hinges on the bottom,” Rice said.
The incident has lead the Federal Aviation Administration to ground 171 of the Boeing 737 Max 9 planes for inspections, impacting flights nationwide and in the Bay Area.
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With the NTSB saying the investigation could take anywhere from 12 to 18 months, Rice said he could understand why people might be concerned about booking a flight.
“Obviously, the public is going to be concerned. They’ve got to understand that these aircraft are going through rigorous safety checks. The flight crews are doing their utmost to make sure the aircraft is safe.”
