United hopes to resume service on Boeing Max 9 jets as early as Sunday

“We grounded the Boeing 737-9 Max within hours of the incident over Portland and made clear this aircraft would not go back into service until it was safe,” FAA Administrator Michael Whitaker said in a statement. “The exhaustive, enhanced review our team completed after several weeks of information gathering gives me and the FAA confidence to proceed to the inspection and maintenance phase.”

The move comes despite the fact that federal investigators have not announced an exact cause of the Alaska Airlines incident. The National Transportation Safety Board is still investigating the accident, in which a portion of the aircraft known as a “door plug” fell off the jetliner shortly after the flight left Portland International Airport. The part was recovered and is currently being analyzed by NTSB investigators.

The FAA approved the detailed set of inspection and maintenance instructions after conducting a thorough review of data following inspections of 40 of the grounded planes. In preliminary inspections of the jets, United and Alaska said they discovered loose bolts on the planes in their fleets.

Whitaker said there is no timeline for when the jets will be cleared to resume service, emphasizing that safety is the FAA’s agency’s most important priority. The agency grounded 171 of the planes the day after the Alaska Airlines’ accident.

Whitaker also said the FAA will not allow Boeing to expand production of its Max jets until a thorough review of the company has been completed.

“This won’t be back to business as usual for Boeing,” he said. “We will not agree to any request from Boeing for an expansion in production or approve additional production lines for the 737 Max until we are satisfied that the quality control issues uncovered during this process are resolved.”

The FAA’s announcement comes just hours after David Calhoun, Boeing’s chief executive, wrapped up a series of meetings with lawmakers on Capitol Hill. Those he met with included Sen. Maria Cantwell, (D-Wash.) chair of the Commerce, Science and Transportation Committee, who said she plans to hold hearings into the matter and Sen. Jerry Moran, (R-Kan.), whose state is home to one of Boeing’s major partners, Spirit AeroSystems.

Sen. Richard Bluementhal, (D-Conn.) said earlier Wednesday that he would not feel safe flying on the Max 9.

After the FAA’s announcement Wednesday evening, he said he would want details of the inspection protocol along with confirmation that they had been carried out, and still had outstanding questions about the design of the door plug.

“The fact that there is a protocol is reassuring but it has to be implemented,” Blumenthal said. “Until they’ve done the inspections, there’s a cause for concern about safety.”

The NTSB said one of their investigators will be returning to Boeing’s 737 factory in Renton, Wash., on Friday a part of the probe. Investigators are trying to built a timeline from the early stages of the production of the door plug to the accident flight.

United and Alaska airlines, the only two U.S. carriers that have 737 Max 9 aircraft in their fleet, have been forced to cancel hundreds of flights as a result of the grounding order. In an interview with NBC News on Tuesday, Ben Minicucci, chief executive of Alaska Airlines said he was “angry” with Boeing.

Scott Kirby, United’s chief executive said this week, said the carrier expects to post a loss for the first quarter of 2023 as a result. Kirby also said the company was weighing alternative plans for future growth out of concern the accident will delay certification of a larger version of the plane, the Max 10.