Boeing said Thursday it has completed development of the software fix for the 737 MAX flight-control system that malfunctioned on the two flights that crashed in Indonesia and Ethiopia and has finished simulator and flight tests of the new system.

After the first crash, of a Lion Air jet, Boeing told U.S. pilots at the end of November that it could have the software fix ready in about six weeks. More than 14 weeks later, with Boeing still working on the software fix, the Ethiopian Airlines jet crashed when the same system malfunctioned.

In all, it’s taken Boeing four times longer to develop the software fix than it projected back then.

Boeing now awaits approval from the Federal Aviation Administration (FAA), which must fly a certification flight and also review all the manufacturer’s documentation on the changes made to the flight-control system before the MAX can be recertified and cleared to reenter commercial service.

The news comes ahead of a crucial meeting next week of civil aviation authority officials from around the world, convened by the FAA in Fort Worth, Texas, to try to arrive at an international consensus on what’s needed before the MAX is allowed to fly passengers again.

The manufacturer said it has flown flight tests with the updated software for more than 360 hours on 207 flights.


Boeing said the FAA has asked for additional information before it will conduct a certification flight, including details on how pilots interact with the airplane controls and displays in different flight scenarios. The company is now providing that information.

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Boeing Chairman and Chief Executive Officer Dennis Muilenburg in a statement cited “clear and steady progress” toward updating the MAX so that it will “be one of the safest airplanes ever to fly.”

“We have completed all of the engineering test flights for the software update and are preparing for the final certification flight,” said Muilenburg. “We’re committed to providing the FAA and global regulators all the information they need, and to getting it right.”

On Nov. 27, a month after the Lion Air crash and a day before the preliminary report into that crash was released, Boeing Vice President Mike Sinnett briefed American Airlines pilots in a meeting in Dallas and told them Boeing was working on “software that would significantly reduce the probability of it happening again.”

According to an audio recording of the meeting that was provided by the Allied Pilots Association (APA), the airline’s pilot union, when the American pilots pressed Sinnett for faster action, he laid out a six-week timeline to develop the fix, followed by a 90-day period for the FAA to review and mandate its implementation.

“Our typical software revision process is about six months to a year. We’re talking six weeks,” Sinnett told the APA pilots. “We’re talking about moving relatively quickly.”

That meeting was 24 weeks ago.

Last month, speaking at a leadership forum at the George W. Bush Presidential Center in Dallas, Muilenburg said Boeing is “taking a comprehensive, disciplined approach and taking the time to make sure that we get it right.”


In a statement Thursday, APA President Captain Daniel Carey cited the November meeting and said, “It’s six months later and who knows how long it will take to implement the new fix, and if it’s even sufficient.”

“Dennis Muilenberg and his engineers need to take full responsibility for the 346 deaths,” Carey added. “Boeing needs to stop dodging responsibility and stop blaming dead pilots for its mistakes.”

With Boeing almost finished with its software fix, the next step will depend on the FAA.

An FAA spokesman said Thursday the agency will “clear the aircraft for return to flight only after we’re satisfied that the safety concerns have been addressed.”

Boeing has separately developed enhanced training and educational materials that are now being reviewed with the FAA, global regulators and airline customers to support the jet’s return to service. The company said it will hold a series of regional customer conferences around the world to inform customers of the new training requirements.


Correction: This story originally misstated the location of the May 23 meeting of international civil aviation authorities convened by the FAA. It will take place in Fort Worth, Texas.