New York (AFP)

Boeing is in the final stretch to finalize the required changes to obtain the lifting of the flight ban on the 737 MAX, grounded for almost six months after two accidents that claimed the lives of 346 people, according to reports. sources close to the file.

The aircraft manufacturer has finished working on the fix anti-stall MCAS, implicated in the two dramas, says one of these sources on condition of anonymity.

Boeing, on the other hand, continues to make changes to the flight control system, a flaw was detected in late June by the Federal Aviation Agency (FAA), added another source.

This problem requires an update of the flight control software, not a replacement of failed parts, which is longer and more expensive, says the source.

Refusing to "speculate", the aircraft manufacturer repeats that its schedule provides a presentation of changes to regulators in the current month for a return to the sky of the MAX in the fourth quarter.

"Our best estimate is a return to service of the MAX from the beginning of the fourth quarter," in other words, in October, a spokesman told AFP on Tuesday.

At an August meeting in Seattle, West, however, Boeing was unable to respond to questions from US, European and Brazilian aviation regulators about technical changes to the flight control system.

CEO Dennis Muilenburg could provide more precise information on the schedule when he is scheduled to speak at a conference on September 11 in California (West).

For the US authorities, the date on which the test flight will be required to return the 737 MAX to service depends on the progress of the modifications requested from Boeing.

- Dissensions -

A few months ago, the aircraft manufacturer had already submitted or was preparing to submit MCAS fixes to the FAA before being asked to review its copy or provide additional information.

It is therefore not sure that Boeing this time respects its own schedule, warn the sources, especially as there remain two major obstacles.

The structure of the major air traffic regulators, set up by the FAA after criticism of its close ties with Boeing, said on August 30 it took much longer to finalize its work documenting the changes made on the 737 MAX.

This Joint Task Force, JATR (Joint Authorities Technical Review), includes authorities from Australia, Brazil, Canada, China, Indonesia, Japan, Singapore and the European Union through European Aviation Safety Agency (EASA).

Pilot training remains a divisive issue, particularly for Americans, Europeans and Canadians.

Europeans demand simulator training, according to a source familiar with the issue, as do Canadians.

The Americans believe that the drivers who master the 737 NG, a version before the MAX, need only computer or iPad training.

Discussions on this delicate subject are continuing, but a decision has been postponed at the very end of the modified MAX approval procedure.

Will Europeans and Chinese (in the midst of a trade war with the United States) accept the changes brought by Boeing? Many experts are skeptical and do not see the MAX in the global sky before the first quarter of 2020.

"We are still on a return in service in the first quarter, at best," says Michel Merluzeau, expert at Air Insight Research.

After a significant shortfall in the first and second quarter, US airlines have already taken the lead to avoid inconvenience during the crucial holiday season.

American Airlines and United have finally decided recently, after weeks of hesitation, to extend the cancellation of scheduled flights on the 737 MAX until December 3 for the first and December 19 for the second.

Southwest Airlines, the MAX's largest customer with 34 aircraft in service before the grounding of this aircraft, did not wish to take risks and preferred to cancel all flights until early January 2020. Ditto for Air Canada.

© 2019 AFP