Inspections of the 737 MAX have been delayed as Boeing reviews its guidance

Federal regulators said Tuesday that Boeing is reviewing its instructions on how airlines inspect its 737 Max 9 jet, delaying the manufacturer's efforts to get the plane back in the air after a panel on one of the planes exploded during a flight late last week.

The FAA said the company would change the instructions it issued Monday based on feedback, but the agency did not provide further details. Instructions on how to comply with FAA rules are often drafted and distributed by aircraft manufacturers, with input from airlines and the federal agency to ensure they can be followed consistently by technicians.

“Upon receiving the revised version of the instruction from Boeing, the FAA will conduct a comprehensive review,” the FAA said in a statement. “Public safety, not speed, will determine the timeline for the Boeing 737-9 MAX’s return to service.”

The announcement that Boeing is reviewing the instructions comes after two airlines reported finding disassembled parts in the panel area under inspection.

The Federal Aviation Administration said Saturday it would require inspections of planes after one of those panels was blown off during an Alaska Airlines flight that took off from Portland, Oregon, the day before. Although no serious injuries were reported, the accident exposed passengers to strong winds and raised new concerns about Boeing's quality control practices. The accident also forced airlines operating Max 9 aircraft to cancel dozens of flights.

The explosion is the latest in a series of setbacks for Boeing, which has struggled to regain public trust after two Boeing 737 Max 8 crashes in 2018 and 2019 that killed 346 people.

It was not immediately clear how Boeing's initial plan failed. The company said Monday morning that it has shared instructions with airlines on how to inspect the damaged panel, also referred to as a door plug, which covers the space where the exit door will be installed. Hours later, the FAA said it had “agreed on a method to comply” with the agency's order issued Saturday, appearing to confirm Boeing's statement. Inspections focus on door seals, door components and fasteners.

After these announcements, Alaska Airlines and United, the two largest operators of the Max 9, said they had found disassembled parts during initial inspections of the panel.

Investigators with the National Transportation Safety Board found a door seal on an Alaska Airlines plane, but said Monday they were still searching for some related parts.

Boeing CEO Dave Calhoun addressed employees at a meeting Tuesday afternoon, promising transparency in the company's response.

“We're going to deal with this — No. 1 — by owning up to our mistake,” he said, speaking from a factory in the Seattle area where the company makes planes, including the Max, according to excerpts provided by Boeing. “We will address this 100 percent and with complete transparency every step of the way.”

Mr. Calhoun, who took charge of the company in January 2020 after his predecessor was forced to resign during the previous Max crisis, said the company would work closely with federal investigators. He also said he was moved when he saw a photo from the accident for the first time. A teenage boy and his mother, neither of whom were seriously injured, were sitting next to the painting that exploded.

“I have children, I have grandchildren, and so do you,” he said. “These things are important. Every detail is important.”

During Friday's flight, which was carrying 171 passengers and six crew members, the pilots and flight attendants had difficulty communicating with each other after the panel exploded. Jennifer Homendy, head of the safety board, said during a press conference on Monday evening that the crew members were surprised when the door separating the cockpit from the passenger cabin opened. This exposed the pilots to strong winds and cabin noise, making it difficult for them to hear each other and communicate with air traffic control.

Ms Homendy said the cockpit door was designed to open during a rapid decompression event, but the crew was not aware of this feature on the plane. She said Boeing plans to make changes to its manual to inform crews.

The Alaska plane was at an altitude of 16,000 feet when the panel exploded, but the accident could have been more catastrophic if it had been at a higher altitude. If the plane had been flying at more than 30,000 feet, passengers would have moved around the cabin and would have less time to safely put on oxygen masks and buckle up.

As a first step, the agency will work closely with Boeing to develop a process to ensure all door jacks on 737 MAX 9 planes are properly secured, former FAA acting administrator Billy Nolen said in an interview.

The result should be detailed instructions telling airlines how to properly inspect doors, complete with diagrams of the pins and screws that attach the door seals to the plane. The guidance will then be reviewed and approved by the FAA. The agency said it expects airline employees to spend between four and eight hours inspecting each plane.

After the panel explosion on Friday, some airlines began preliminary inspections while they waited for formal instructions from Boeing approved by regulators, said Mr. Nolen, who previously headed the Federal Aviation Administration's Office of Aviation Safety.

“My understanding is that they need a detailed set of standards issued by Boeing, approved by the FAA,” he said. “They have to review it and sign it.”

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