The plug was found covering an unused exit door that exploded for minutes on an Alaska Airlines flight Friday evening, according to the National Transportation Safety Board. The agency's head said the discovery could prove crucial in investigating the cause of the air accident that forced the Boeing 737 Max 9 to return to Portland, Oregon, minutes after takeoff.
The Federal Aviation Administration has grounded all Boeing 737 Max 9s involved until it is “confident that they are safe,” an FAA spokesman said in a statement on Sunday.
In a news conference Sunday evening, Jennifer Homendy, chairwoman of the National Transportation Safety Board, said the plug was found near Portland in the backyard of a teacher she identified only as Bob. “We’re really happy Bob found this,” she said.
Click here to view related media.
Click to expand
Portal news agency said it had previously told reporters that the plane part was a “key missing component” in trying to figure out why the accident occurred.
Homendy told reporters that pilots reported that the same plane received three pressure warnings from the cockpit dashboard light between December 7 and January 4. At least one occurred during the flight.
The aircraft was only a few weeks old and was delivered at the end of October. Alaska Airlines maintenance crews checked and turned off the light after each lighting.
The day before the explosion, Homendy said, the airline ordered that the stricken plane not be allowed to make long flights over water so that it could “return to an airport very quickly” if the warning light came on again. She stressed that the light may not be related to Friday's incident. In addition, further maintenance was ordered – essentially a deeper investigation into why the light continued to illuminate – but none was carried out before Friday night's flight.
Homendy described a chaotic scene in the plane's cockpit and just outside the cockpit after the explosion.
She said the flight crew heard a bang and the cockpit door “flew open” due to the loss of pressure. They immediately put on their masks, but communication in the cockpit and between crew members in the cabin and in the cockpit was very difficult.
The force of the depressurization sent the cockpit door crashing into the front lavatory door, damaging the lavatory door and requiring a flight attendant three attempts to close the cockpit door, Homendy said.
She noticed that the first officer lost her headset and the captain had part of his headset removed. The captain and first officer could no longer hear in their damaged headsets after they were recovered, so they used the ceiling speaker to listen.
A short reference checklist kept handy for the flight crew also flew out the door, Homendy said, adding that it was incredibly loud and chaotic on board.
Homendy said the flight data recorder and cockpit voice recorder were sent to NTSB labs for readout on Sunday, but no data was available on the cockpit voice recorder because it was not retrieved within two hours, as restarts and earlier Data recorded will be deleted, according to Portal news agency, which also adds that the NTSB has pushed to increase cockpit voice recording requirements to 25 hours.
The FAA's emergency airworthiness directive grounding many of the Max 9s affects about 171 aircraft worldwide. Such orders are issued, according to the agency, “when an unsafe condition exists that requires immediate action by an owner/operator.”
“The FAA’s top priority is to ensure the safety of the flying public,” the FAA spokesman said.
What happened on the Alaska Airlines flight?
The flight from Portland, Oregon, to Ontario, California, lasted just a few minutes and had reached an altitude of about 16,000 feet when the door plug popped off, an NTSB official said during a news conference Saturday. The gaping hole in the side of the jet opened where Boeing installed a plug to cover an emergency exit that the airline does not use, The Associated Press explained.
Homendy called the event an “accident, not an incident.” She said the plane was forced to return to Portland International Airport just minutes after takeoff “after a door plug in the middle of the cabin … exited the aircraft, resulting in rapid decompression.”
The two seats next to the demolished part are unoccupied, Homendy said. None of the 171 passengers or six crew members suffered serious injuries, Homendy said. The NTSB said Sunday that the plane suffered no structural damage.
Who is investigating the incident?
The FAA, NTSB, Boeing, Alaska Airlines, the Airline Pilots Association and the Association of Flight Attendants are all investigating, officials said.
The FBI is also assisting local law enforcement in searching for parts that came loose during the flight. A spokesman for the FBI's Portland office said the agency remains “on call.”
The NTSB asked anyone with images and videos to contact [email protected].
How are airlines and Boeing reacting?
In the US, only Alaska Airlines and United Airlines use the Boeing 737 Max 9 aircraft.
Alaska Airlines temporarily grounded its entire 737-9 MAX fleet pending inspections, the company said. The airline said it canceled 160 flights on Saturday, affecting about 23,000 passengers, another 170 flights on Sunday, affecting about 25,000 passengers, and 60 on Monday. “We expect further significant cancellations in the first half of the week,” the airline said on Sunday evening.
United said Sunday: “Operations of United’s Boeing 737 MAX 9 aircraft remain temporarily suspended while inspections required by the FAA are completed. We continue to work with the FAA to clarify the inspection process and requirements for returning all MAX 9 aircraft to service.” “We are working with customers to accommodate them on other flights and have been able to avoid cancellations in some cases by switched to other types of aircraft.”
Agence France-Presse reports that airlines and regulators worldwide grounded some versions of the Boeing 737 MAX 9 planes, including Turkish Airlines.
Boeing has so far delivered around 218 of the 737 MAX aircraft worldwide, the company told the AFP news agency.
A Boeing spokesman said it “fully supports the FAA's decision to require immediate inspections of 737-9 aircraft with the same configuration as the affected aircraft.”
Boeing President and CEO Dave Calhoun told employees Sunday that he would host a “company-wide safety webcast” on Tuesday. He also canceled a Boeing vice president leadership summit that was scheduled to take place on Monday and Tuesday to “focus on our support for Alaska Airlines and the ongoing investigation by the National Transportation Safety Board, as well as all of our airline customers, the impact on their fleets have”. Calhoun wrote.
Previous research on Boeing 737 aircraft
There are currently two versions of the Boeing 737 in service: the Max 8 and the Max 9.
In 2018, a Lion Air plane carrying a Boeing 737 Max 8 crashed into the sea. The following year, an Ethiopian Airlines plane of the same model crashed shortly after takeoff. More than 300 people were killed in the two accidents. The jets were discontinued in March 2019. The Boeing 737 Max was allowed to return to service at the end of 2020.
In April, Boeing halted production of the 737 Max due to a problem with aircraft parts.
Homendy said after Friday's incident that the NTSB did not suspect there was a design problem with the aircraft overall.
More from CBS News
Aliza Khasan