EFEBy Andy Pasztor Fort Worth (USA)

Acting Federal Aviation Administration chief Daniel Elwell appeared to undermine industry expectations that Boeing's grounded 737 MAX jets would be heading toward a smooth and predictable return to the skies, according to a Dow Jones Newswires report made available to EFE on Thursday.

Elwell repeatedly told reporters at a news conference Wednesday that he couldn't predict when the fleet would be back in the air, suggesting instead that the process of approving a proposed software fix for the aircraft remains open-ended and subject to various factors - many outside his control.

Some of his comments seemed to signal potentially months of additional delay, as Elwell appeared to distance himself from plans by some United States airlines to put the jets back into operation in August.

"If you said October, I wouldn't even say that" was a realistic deadline at this point, Elwell said, because "we haven't finished determining exactly what the training requirements will be." He didn't elaborate or offer any alternative dates.

The FAA has called a meeting with regulators from 30 countries to discuss progress in fixing the 737 MAX's software.

Thursday's closed-door meeting, originally described by FAA officials as a way for the agency to secure an international stamp of approval for the fix, is now shaping up largely as an information-sharing exercise, according to Elwell's remarks.

To stress that approval to return the 737 MAX to flight would be driven by analysis rather than the calendar, Elwell, a former commercial pilot, suggested he wouldn't balk even "If it takes a year to find everything we need, to give us the confidence" to act.

Industry and government officials closely following the discussions don't believe it would take nearly that long to implement a fix.

The planes were grounded worldwide in March following two fatal crashes in less than five months. In both cases, the jets nose-dived, triggered by a flight-control system that Boeing and the FAA intend to make less potent and easier for pilots to override via the pending software fix.

The FAA has been assessing different versions of the fix since late January, and the agency initially issued an update to airlines and pilots saying it hoped to certify a fix by April. Boeing was close to submitting a final version to the agency in late March, FAA officials said Wednesday, but an internal corporate review uncovered some last-minute technical problems.

Since then, officials at the FAA and Boeing have signaled several likely timetables that have all fallen through, Dow Jones added in a report made available to EFE.

Last week, Elwell told a House aviation subcommittee that the FAA expected to formally receive Boeing's software fix sometime this week.

In addition to verifying the revised software, the FAA has to establish new training requirements, create enhanced maintenance standards and - most important - persuade foreign regulators to endorse the bulk of the eventual US plan.

Asked if the FAA faced a crisis of confidence, Elwell acknowledged there may be such concerns.

But, he added, "I'm not worried about the future of public confidence, because I'm not worried about the future of aviation safety" once the final 737 MAX fixes are implemented.

FAA officials declined to specify the engineering challenges that have delayed certification. "The reviews of software changes are complicated and take time," Elwell said, following a day of technical sessions here that included US and foreign aviation officials.

After Boeing formally submits its software package and the FAA tests it in the air, an outside technical panel established by the agency will weigh in with its findings and recommendations.

Changes at that point could prompt further evaluation by the FAA's own employees.

At Thursday's session, FAA officials will detail progress so far and seek suggestions from foreign participants. Weeks ago, air-safety regulators for Canada and the EU said they planned to conduct separate reviews of changes to the automated flight-control feature, called MCAS, along with a safety assessment of the entire aircraft.

"Other countries and other authorities may take longer" to put the planes back into service, Elwell said, "and they undoubtedly will." Meanwhile, the FAA is asking foreign regulators "what else they would like to see from us," Ali Bahrami, the FAA's top safety official, told reporters.

Airline officials, however, don't see the FAA's ultimate decision as the last word in restoring passenger confidence. United Airlines Chief Executive Oscar Munoz said the airline isn't taking it for granted that customers would be willing to fly the MAX again "just because somebody says it's safe."

At the carrier's annual shareholder meeting, Munoz said once the MAX is flying again, United will make it clear to passengers if they are flying on one and will re-book those who have concerns.

Munoz also said he plans to fly on United's first MAX flight. "Pushing for a timeline" to resume flying, he said, is less important than "returning it safely and getting the perception of the flying public to know that it's safe."

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