The Federal Aviation Administration (FAA) grounded all MAX 9s operated by Alaska and United and some flown by foreign airlines after a terrifying flight on Friday night.
The Boeing jet that suffered an in-flight blowout over Oregon was not being used for flights to Hawaii after a warning light that could have indicated a pressurisation problem lit up on three different flights.
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, Jennifer Homendy, chair of the National Transportation Safety Board, said on Sunday.
Homendy cautioned that the pressurisation 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 km) over Oregon.
On Monday, the FAA approved guidelines for inspecting the door plugs on other MAX 9 jets and repairing them, if necessary. That move could speed the return to service of the 171 planes that the FAA grounded.
Alaska has 64 other MAX 9s, and United Airlines owns 79 of them. No other US airlines operate that model of the Boeing 737.
Shares of The Boeing Co fell 8 per cent and those of Spirit AeroSystems, which builds the fuselage for Boeing’s 737 MAX, tumbled 11 per cent on Monday, the first day of trading since the incident. Shares of Alaska Airlines were nearly unchanged after slumping earlier in the session.
The auto-pressurisation system warning on the ill-fated Alaska Airlines jet lit up during three previous flights. Homendy said she did not have details about a December 7 incident, but that it came on again during a flight on January 3 and after the plane landed on January 4 – the day before the blowout.
US investigators recover key part from Alaska Airlines 737 MAX jet
US investigators recover key part from Alaska Airlines 737 MAX jet
“We plan to look at that more, and we’ve requested documentation on all defects since delivery of the aircraft on October 31,” she said.
The NTSB said the lost door plug was found on Sunday near Portland, Oregon, in a the back garden of a home. Investigators will examine the plug, which is 26 by 48 inches (66 by 121cm) and weighs 63 pounds (28.5 kilograms), for signs of how it broke free.
Investigators will not have the benefit of hearing what was going on in the cockpit during the flight. The cockpit voice recorder – one of two so-called black boxes – recorded over the flight’s sounds after two hours, Homendy said.
Boeing Max grounding goes global as carriers follow FAA order
Boeing Max grounding goes global as carriers follow FAA order
At a news conference on Sunday night, Homendy provided new details about the chaotic scene that unfolded on the plane. The explosive rush of air damaged several rows of seats and pulled insulation from the walls. The cockpit door flew open and banged into a lavatory door.
The force ripped the headset off the co-pilot and the captain lost part of her headset. A quick reference checklist kept within easy reach of the pilots flew out of the open cockpit, Homendy said.
Two mobile phones that appeared to have belonged to passengers on Friday’s flight were found on the ground. One was discovered in a garden, the other on the side of a road. Both were turned over to the NTSB.
The plane made it back to Portland, however, and none of the 171 passengers and six crew members was seriously injured.
Hours after the incident, the FAA ordered the grounding of 171 of the 218 MAX 9s in operation, including all those used by Alaska Airlines and United Airlines, until they can be inspected. That led to flight cancellations at both carriers.
Early on Monday, Alaska Airlines was forced to cancel 20 per cent of all flights, 141 in all. United cancelled 221 flights, or 8 per cent of its total flights scheduled for Monday.
Boeing chief executive Dave Calhoun called a companywide webcast to talk about the incident with employees and senior leadership for Tuesday.
“When serious accidents like this occur, it is critical for us to work transparently with our customers and regulators to understand and address the causes of the event, and to ensure they don’t happen again,” Calhoun wrote in a message to employees on Sunday. “This is and must be the focus of our team right now.”
Boeing checks hit paperwork snag; US investigators search for missing part
Boeing checks hit paperwork snag; US investigators search for missing part
The MAX is the newest version of Boeing’s venerable 737, a twin-engined, single-aisle plane frequently used on US domestic flights. The plane went into service in May 2017.
Two MAX 8 jets crashed in 2018 and 2019, killing 346 people. All MAX 8 and MAX 9 planes were grounded worldwide for nearly two years until Boeing made changes to an automated flight control system implicated in the crashes.
The MAX has been plagued by other issues, including manufacturing flaws, concern about overheating that led FAA to tell pilots to limit use of an anti-ice system, and a possible loose bolt in the rudder system