Operators of Boeing Co.’s 737 Max 9 have completed inspections on an initial batch of 40 planes, a key step to eventually end the grounding of the aircraft ordered by US regulators in the wake of an accident earlier this month.

The US Federal Aviation Administration will now review findings from those 40 checks to determine whether the Boeing-drafted procedures are appropriate to return the fleet of 171 parked Max 9s to service, the agency said in a statement Wednesday. 

The agency ordered the grounding after a Max 9 operated by Alaska Airlines suddenly lost a fuselage section shortly after takeoff on Jan. 5, sparking a midair emergency and a crisis in confidence in Boeing’s manufacturing processes and a flurry of investigations. 

“Once the FAA approves an inspection and maintenance process, it will be required on every grounded 737-9 MAX prior to future operation,” the agency said. “The safety of the flying public, not speed, will determine the timeline for returning these aircraft to service.”

Wrapping up the initial round of checks is a sign of much-needed progress for Boeing as it works to rebuild trust with regulators, customers and the flying public. Boeing rose 1% as of 12:33 p.m. in New York following the FAA’s announcement, after rising much as 2.9% earlier. The shares had sunk 23% this year through Tuesday’s close, by far the worst performer this year on the Dow Jones Industrial Average.

Spirit Visit

Boeing Chief Executive Officer Dave Calhoun was set to visit the main campus of Spirit AeroSystems Holdings Inc. in Wichita, Kansas, on Wednesday, where the supplier assembles a large part of 737 Max’s main airframe. Calhoun will participate in a town hall gathering with Spirit employees alongside Spirit CEO Pat Shanahan and Chairman Bob Johnson.

The visit comes after Boeing announced multiple steps to bolster quality and oversight at its factories earlier this week. In the wake of the accident, United Airlines Holdings Inc. and Alaska Air Group Inc., the only Max 9 operators in the US, found loose hardware during examinations of the plane’s door plugs. 

The airlines have canceled hundreds of flights since the planes were ordered parked. 

In a video posted to its website, Alaska Airlines CEO Ben Minicucci said the carrier is making “good progress” inspecting its fleet of 65 Max 9s, though it doesn’t know when the planes will be cleared to resume flights.

Shutdown Risk

Separately, the National Transportation Safety Board warned a US government shutdown would pause its investigation into why the panel shot off of Alaska Airlines Flight 1282. Congressional leaders are working to pass a short-term spending measure to avert partial shutdown on Saturday. 

A lapse in funding would “dramatically hinder” the agency’s ability to carry out its investigations and issue safety recommendations tied to its probe of the Jan. 5 accident, NTSB Chair Jennifer Homendy said in a letter to Senator Maria Cantwell, a Washington Democrat. 

If the government shuts down while the FAA’s grounding is still in effect, “there is no known imminent threat to the safety of human life or protection of property that would justify the continuation of ongoing work related to the NTSB’s AK 1282 investigation,” Homendy said in the Jan 17 letter.

Officials from the FAA and NTSB briefed members of the Senate panel responsible for overseeing aviation safety matters about their investigations on Wednesday.