The FAA has ended the grounding of the Boeing 737 Max aircraft.
The order, signed by FAA administrator Steve Dickson Wednesday, authorizes airlines to begin readying Max planes for a return to service on domestic flights. It comes 20 months after aviation authorities around the world grounded the airplane following the second of two crashes over five months that killed a combined 346 people.
Under the new FAA requirements, airlines can't put their Max planes in the air immediately. They must first install new flight control software and make other system upgrades. In addition, airlines must develop new pilot training requirements, including simulator training, in order to familiarize plilots with the plane's automated flight control system.
Airlines must all take required maintenance steps to ready the Max to fly again.
American Airlines is preparing to bring the first of its 24 Max aircraft back into service on Dec. 29. Southwest, which was the world's largest Max operator before the March 2019 grounding of the aircraft, doesn't plan to return the plane to the skies until at least the second quarter of next year.
Aviation authorities in Europe, China and Brazil must still approve Boeing's changes to the Max before airlines can use planes throughout their international networks and before airlines from those regions can put Maxes back in the sky.
Both crashes of Max planes, a Lion Air jet in October 2018 and an Ethiopian Airlines jet in March 2019, were caused by a faulty sensor, which transmitted erroneous information to the planes' automated flight control system, causing the planes to nosedive.
Boeing has addressed that issue by altering the flight control system so that it now compares input from two sensors rather than only one. The aircraft only corrects its angle of attack if both sensors provide the same input. Pilots can also override the aircraft input if necessary.
Dickson himself underwent Max flight training in the early fall and test flew a Max plane for approximately two hours in late September. In a video posted to YouTube Wednesday, he expressed confidence that the aircraft is now air worthy.
" I can tell you now that I am 100% comfortable with my family flying on it," Dickson said.
In its own statement, Boeing said that the Max grounding precipitated a change in corporate culture.
"We will never forget the lives lost in the two tragic accidents that led to the decision to suspend operations," Boeing CEO David Calhoun said. "These events and the lessons we have learned as a result have reshaped our company and further focused our attention on our core values of safety, quality and integrity."
Boeing noted that since the Max was grounded it has realigned its organization, bringing its more than 50,000 engineers together in a single Product & Services Safety unit. In addition, Boeing says it has begun identifying, diagnosing and resolving design issues with a higher level of transparency and immediacy.
Ultimately, however, it will mostly be up to airlines to convince customers that they are safe flying on a Max. American has said that customers will know at the time of the booking if their flight will be operated on a Max.
Southwest on Wednesday launched a 737 Max Resource Center, which offers a timeline for its return of the aircraft as well as information about the changes Boeing has made and Southwest's own assurances about the plane's safety.
Southwest said it would "approach returning the Max to service with the same commitment to training that we've employed for almost 50 years, coupled with an uncompromising and unwavering commitment to safety," CEO Gary Kelly said. "For us, it's a passionate pursuit, and it's among the most important work of our careers."
The ungrounding order Wednesday was also met with approval by the Air Line Pilots' Association (ALPA) union.
"ALPA believes that the engineering fixes to the flight-critical aircraft systems are sound and will be an effective component that leads to the safe return to service of the 737 Max," reads a union statement.
Consumer advocacy groups, however, are more circumspect. In a letter to the CEOs of the four U.S. Max operators, which include United and Alaska along with Southwest and American, a group of five consumer organizations asked that the carriers amend their contracts of carriage to guarantee that customers who are afraid of flying in a Max can get a full refund of their ticket.
The consumer groups also asked that carriers provide customers and travel advisors with "easily viewable information on the type of aircraft that will be used to operate a flight in advance."