Days after a refrigerator-size hole opened during an Alaska Airlines flight on Friday, investigators are trying to determine if a door plug was properly bolted.
During a late Monday briefing, the National Transportation Safety Board told reporters that investigators were trying to determine if the four bolts meant to hold the door plug in place were actually installed. Those bolts have not yet been found.
"We have not yet determined if they existed there; that will be determined when we take the plug to our lab in Washington, D.C., said NTSB investigator Clint Crookshanks.
The door plug fell from the plane on Friday and was later discovered in an Oregon resident's backyard.
NTSB Chair Jennifer Homendy said even if the bolts are never found, the investigators can use microscopes and other lab equipment to determine if the bolts were used to secure the door plug.
3 infants unsecured during mid-air scare, NTSB chair says
Children under age 2 are allowed to sit in a parent's lap instead of a separate seat, prompting safety concerns from the head of the NTSB.
Meanwhile, the FAA has grounded 171 Boeing Max 9 planes, the same model used in Alaska Airlines Flight 1282. United Airlines said it is looking at how the door plug is installed on its planes.
"Since we began our preliminary inspections on Saturday, we have found instances that appear to relate to installation issues in the door plug – for example, bolts that need additional tightening," the airline said.
Homendy said she is aware of the reported safety issues with bolt installation.
"We're really focused on this aircraft, however, we are not shy about going broader than just this aircraft," she said. "We need to first and foremost figure out what happened here on this aircraft. If we have a bigger systemwide or fleet issue, we will issue an urgent safety recommendation to push for change."
Homendy, however, stopped short of saying that missing bolts are what caused the door plug to cause Friday's rapid decompression of the airplane. She said investigators would "follow the evidence."
Crew gives interview to investigators
Members of the flight crew met with investigators from the NTSB to describe what took place as the plane rapidly depressurized at 16,000 feet above ground moments after takeoff.
They described a very loud environment, chaotic," Homendy said. "At the time, they heard a bang and then some air, some pressure changes in their ears. They mentioned that the door had flown open at the same time a flight attendant had attempted to close it a few times, eventually succeeded in that. One of their laminated checklists flew out the door when the door also opened. They described it as very loud, windy at the time, and they had trouble communicating, they had trouble hearing each other, they had trouble hearing air traffic control and they had trouble communicating throughout the event.
"I will say once again, excellent job by the entire flight crew, those in the cockpit and those in the cabin, and also air traffic control."
