Airlines on Monday were told exactly how to inspect the 737 Max 9 from Boeing and the Federal Aviation Administration two days after one of jets suffered a dangerous failure during a flight.
The F.A.A. required the inspections on Saturday, a day after a portion of a plane was blown away during an Alaska Airlines flight near Portland, Ore. Airlines, particularly Alaska and United Airlines, which have the most Max 9 jets in their fleets, had parked the planes over the weekend as they waited for Boeing and the F.A.A. to provide the instructions.
In a statement, the F.A.A. said the required inspections will focus on “plugs” put in place where exit doors would otherwise be fitted, door components and fasteners. The part of the plane that was ripped out, at an altitude of 16,000 feet, included one such plug.
“Our teams have been working diligently — with thorough F.A.A. review — to provide comprehensive, technical instructions to operators for the required inspections,” Stan Deal, the chief executive of Boeing’s commercial plane unit, and Mike Delaney, the chief aerospace safety officer, said in a message to employees of that unit on Monday.
The F.A.A. has previously said that it would take four to eight hours to inspect each plane. Inspecting the nearly 200 Max 9 planes in the United States, according to the aviation agency, could take a few days. But it is unclear exactly how many jets were laid out in the same way as the ill-fated Alaska plane. European aviation regulators said on Monday that the version of the jet used there was configured differently and did not need to be inspected.
Aviation regulators and Boeing said that the inspections are unique to the Max 9 and not other versions of the Max jet. The Max 9, along with the more popular Max 8, was grounded for nearly two years after two fatal crashes of the Max 8 in 2018 and 2019.
In a statement on Monday, Alaska Airlines said that its technicians have prepared its Max 9s for inspections, but it was still waiting for the F.A.A. to affirm that the airline’s inspection process complies with the agency’s order. Alaska said it is also still developing detailed instructions and processes for its technicians to follow.
Federal authorities investigating the incident, which resulted in no serious injuries, are also looking into what set off pressurization warnings on the damaged plane during three recent flights. Alaska Airlines workers reset the system and the plane was put back into service, though the airline restricted it from being used on flights to destinations like Hawaii, the chairwoman of the National Transportation Safety Board, Jennifer Homendy, said at news conference on Sunday night.
Asked about its response to the warnings, Alaska Airlines said that it could not answer questions involving the plane and what led to the blowout without approval from the safety board, which is leading the federal investigation. But Alaska said that it had asked the N.T.S.B. to share more information and would do so if allowed. In such investigations, parties are restricted in what they can share publicly.
Boeing’s chief executive, Dave Calhoun, plans to host a companywide safety meeting on Tuesday to discuss the company’s response to the episode and reaffirm its commitment to safety. Boeing is still working to secure approval of the smaller Max 7 and larger Max 10.
Boeing shares were down about 7 percent at 2 p.m. on Monday, and shares of Spirit AeroSystems, which makes the body for the plane, were down about 7 percent, too.