(Bloomberg) — Boeing Co. and federal regulators are preparing to hold a critical set of test flights on the 737 Max early next week, and laying plans for other milestones toward ending the jetliner’s 15-month grounding including convening a panel of pilots to go over a proposed training course.Aviation industry officials briefed on the plans, which still haven’t been finalized, said that the U.S. Federal Aviation Administration has reviewed Boeing’s safety analysis of fixes it has made and is comfortable moving to the next step: putting the plane through its paces with test pilots.The first of several days of test flights could come as early as Monday, according to three people familiar with the plans who weren’t permitted to discuss the still-tentative situation publicly. Boeing had privately targeted hosting the FAA flights by the end of June.“The team is making progress toward FAA certification flights in the near future,” the agency said in a statement.“The FAA is reviewing Boeing’s documentation to determine whether the company has met the criteria to move to the next stage of evaluation,” the agency said. “We will conduct the certification flights only after we are satisfied with that data.”Boeing declined to comment.Regulators and Boeing are also hoping to convene an international panel of airline pilots to test a proposed new training course for Max flight crews, possibly in late July and early August, the people said.Travel restrictions related to the global pandemic have added uncertainty to how such sessions would occur. Plans are being discussed to allow the group to perform its work remotely in flight simulators around the world, rather than flying to Boeing’s main training center in Miami, Florida, where a Covid-19 outbreak is raging.Boeing pared losses on Bloomberg’s report of the certification flight and declined 2.8% to $170.01 at the close in New York. The shares had tumbled as much as 4.2% in the trading session after Bernstein analyst Douglas Harned downgraded the company to the equivalent of “hold.” He cited uncertainty over the 737’s comeback and the prospect of a pandemic disrupting air travel through mid-decade.Setting a date for certification flights is one of the most critical steps on Boeing’s road to resuming service on its best-selling jet, which was grounded in March 2019 amid a worldwide furor following the second fatal crash in less than five months.However, several more hurdles remain before the plane can get its final certification from regulators. Airline customers have been told that it could come as soon as September if all goes well.For one, FAA Administrator Steve Dickson and his deputy, Dan Elwell, both of whom were airline pilots, plan to also fly the plane after the certification flight in an attempt to reassure the public.The controversial issue of new training must also be addressed. Boeing decided in January to ditch its long-held stance that pilots of an older 737 model would only need a short computer course to fly the Max, a crucial selling point before the crashes.As well as working with the international pilots, a group known as the Joint Operations Evaluation Board, the FAA is also convening its own group to evaluate training.The FAA’s Flight Standardization Board will propose minimum training requirements and give the public a chance to comment before finalizing them.Additionally, the FAA and its counterparts in other countries will have to legally mandate that repairs to the plane are performed before it carries passengers. Governments will also lay out requirements for inspections and maintenance on the almost 400 planes around the world that haven’t flown since the grounding.And, even if regulators approve the Max’s return to service later this year, that likely won’t be the end of required changes to the plane. Regulators have told Boeing to expect that additional requirements will be phased in, according to people familiar with the discussions.The test flights will come after more than a year of harsh criticism from Boeing’s skeptics, multiple investigations of the plane and a federal criminal probe.Successfully completing the tests would provide some rare good news for Boeing and CEO Dave Calhoun at a time when the aviation industry is reeling from the Covid-19 pandemic and could help unlock billions of dollars in inventory from about 450 planes the company has built but been unable to deliver.“For Boeing, it could close a chapter that’s gone on longer than they wanted and kills a lot of speculation in the marketplace that the plane will never fly again,” said George Ferguson, an analyst with Bloomberg Intelligence. Some short sellers have fanned speculation that the jet will never return.(Updates shares with closing price in ninth paragraph. An earlier version of this story was corrected to show that Bernstein cut its recommendation on Boeing shares to hold.)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.