New York (AFP)

The US Aviation Agency (FAA) said on Thursday it had warned other air regulators that it was still working with Boeing to resolve an electrical problem that affects a total of "about 106 planes" 737 MAX , including 71 in the United States.

The aircraft manufacturer had asked at the beginning of April 16 companies operating its flagship aircraft to no longer fly certain devices, without giving details on the number, the time to allow the verification of a problem in the electrical supply system.

The FAA said Thursday in a notice sent to other aviation agencies that it was continuing to work with Boeing "to fully identify the extent of a power supply and grounding problem that is affecting some 737 MAXs. and find a solution ".

The manufacturer had initially indicated that the problem could affect "the operation of an emergency power control unit," the FAA said in a message sent to AFP.

"Analysis and testing subsequently showed the problem could involve additional systems," the agency added: a circuit breaker panel and the main dashboard.

However, no incident related to this potential defect has been reported.

The general manager of the aircraft manufacturer, Dave Calhoun, had indicated on Tuesday that he could not give a specific date on the return to service of these devices, but that once the FAA has validated the proposed remedy, the latter can be implemented "in a few days".

An American Airlines official, who had to set aside 18 737 MAX planes, said Thursday to wait for the instructions to be implemented.

"We hope that it will be a story of a few weeks, and no more," said Robert Isom.

Southwest Managing Director Gary Kelly said the issue was "disappointing".

"It's a production problem, fairly minor, fairly easy to resolve, but you can't afford to risk the slightest consequence and everyone is acting as a precaution," he said in an interview on CNBC.

But "we need the MAX because the activity starts to resume", he was annoyed.

The 737 MAX, which was banned from flight in March 2019 after two fatal crashes, was cleared for flight again in November in the United States, and then in most parts of the world, after changes to control software from flight, repositioning of certain cables and new pilot training.

© 2021 AFP