BA Boeing Co

By Andy Pasztor 

Boeing Co. is grappling with still another software problem that has cropped up in its effort to fix its 737 MAX aircraft, adding to technical issues that have complicated and delayed the grounded fleet's return to service over many months.

The latest glitch, which Boeing said Friday it was working to correct, prevents the jet's flight-control computers from powering up and verifying they are ready for flight, according to industry and government officials.

"We are making necessary updates and working with the FAA on submission of this change, and keeping our customers and suppliers informed," a Boeing spokesman said.

Before the problem was discovered last week, according to people briefed on the details, the company and the Federal Aviation Administration were slated to conduct a key certification flight by the end of this month. But at this point, these people said, that date increasingly looks like it will slip into at least February.

The length of the delay will largely depend on how long it takes Boeing engineers to address the problem and verify its elimination, though coordination with international regulators and other factors could complicate the process.

It also isn't clear how much of a delay the problematic software could create in the end since various other regulatory steps affecting the MAX's return, including finalizing pilot-training requirements, are running late and remain in limbo.

U.S. carriers already have pulled MAX jets from their schedules through early June, though industry and government officials project that the planes could start making demonstration flights with airline executives on board weeks before that.

The MAX fleet was grounded in March, not long after the second of two crashes that killed a total of 346 people.

The software problem occurred as engineers were loading updated software -- including an array of changes painstakingly developed over roughly a year -- into the flight-control computers of a test aircraft, according to one person briefed on the details.

A software function intended to monitor the power-up process didn't operate correctly, according to this person, resulting in the entire computer system crashing. Previously, proposed software fixes had been tested primarily in ground-based simulators, where no power-up problems arose, this person said.

The revised software is intended to fix an automated flight-control system called MCAS that led to the two fatal crashes, in 2018 and 2019. The system, new on the MAX, misfired in a way that repeatedly and forcefully pushed the planes' noses down, overpowering pilot commands and ending in fatal dives. The company has been developing revised software intended to make the system less prone to such misfires and easier for pilots to counteract.

Boeing also has increased redundancy by having the plane's dual flight-control computers operate throughout each flight, a change that industry and government officials said has entailed more software changes than Boeing initially anticipated.

FAA and Boeing officials were in the midst of analyzing prospects for the latest software revisions when Steve Dickson, the agency's administrator, met with newly installed Boeing chief Dave Calhoun early this week. Neither government nor Boeing officials have commented on that session.

In addition to completion of the software fixes, the MAX's return to service is subject to test flights by a representative group of international airline pilots, along with public comments on the details of extra training for cockpit crews.

The FAA also has to approve changes to operating and training manuals, endorse revised emergency procedures and sign off on maintenance and inspections of planes that have been in storage, some for many months.

Numerous foreign regulators have signaled they won't approve resumption of passenger flights until their own engineering and pilot-training reviews are finished.

Nevertheless, the coming certification flight is widely considered the next major step to ease the MAX crisis, which has cost Boeing and the global airline industry billions of dollars and disrupted flight schedules around the world.

If resolving the most recent software errors takes longer than a few weeks, the MAX's overall return to service timeline could take another significant hit.

Initially, Boeing and many of its airline customers expected that a software fix dealing solely with the shortcomings of MCAS could be rolled out fairly quickly.

After a Lion Air jet went down in Indonesia in October 2018, the plane maker and FAA experts projected the necessary changes could be made, tested, approved and implemented world-wide in seven months. But as U.S. and international regulators delved into other aspects of the flight-control computers, new safety concerns arose that prompted months of further analysis and testing.

During the summer, changes to emergency procedures and issues regarding reliability of computer hardware prompted more studies and software tweaks. Months later, regulators balked at what they considered Boeing's failure to promptly provide data backing up software changes, prompting another slowdown in the process.

The MAX's return also faces significant challenges when it comes to changes in software used in flight-simulators to train pilots.

Such devices are in short supply world-wide, and some of those that are available have somewhat different software configurations depending on when they were updated and certified by regulators. As a result, some airlines are concerned that pilots trained on early versions may have to be recalled and run through follow-up simulator sessions to comply with eventual safety mandates.

Write to Andy Pasztor at andy.pasztor@wsj.com

(END) Dow Jones Newswires

January 17, 2020 18:56 ET (23:56 GMT)

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