From our correspondent in Washington

The changes "major" on the system of prevention of dropping out. It is as well as Boeing describes the changes he has decided to operate on its model 737 Max, a new version of the aircraft, the most exploited in the world. Involved in two air accidents major these past few months, the small new to the range is going to be reworked by the manufacturer. An early recognition of the existence of a technical problem? The regulator of america's air transport continues to refuse to his side of nail to the ground the Boeing 737 Max, as many countries have done it as a precaution. Unlike authorities in the european, chinese, or indonesian, the Federal Aviation Administration (FAA) confirmed Monday the authorization of commercial flight.

" READ more - Ethiopian Airlines: Boeing shaken by a new crash.

On the other hand, the FAA had given Boeing until the end of the month of April to modify the software of the automatic control system of flight, which seems to have played a role, at least in the first accident of a 737 Max in Lion Air in Indonesia at the end of October, and also, perhaps, in the second drama this time for Ethiopian Airlines. A few months ago that Boeing had to produce an update of this software. Discussions and disagreements between the manufacturer and the FAA have delayed this deadline. The regulator has a date to Boeing, not only to change the software, but also some aspects of the training of pilots as well as their textbooks. The steps to follow to disengage the system supposed to stop automatically dropping out of the plane is in the heart of the problem.

"The investigation (of the accident Sunday in Ethiopia) has just begun and to date it has not informed us of data that can be used to reach conclusions or make decisions," says the FAA. While the world press and a part of the public alarmed by the crash of a succession of two Boeing 737 Max is tempted to conclude that the two incidents share the same cause, the regulator in the us is more skeptical as he does not have elements that are more concrete.

Tuesday morning, the us president, Donald Trump and Dennis Muilenburg, head of Boeing, spoke on the phone shortly after the tweets to Trump the fact that the aircraft have become "too complex" to fly, indicated to the AFP a source on condition of anonymity. The CEO of Boeing has assured the tenant of the White House that the 737 MAX 8 was "safe" and "reliable" in spite of the decisions of several countries, including Europe, to close their airspace.

All the us airlines, such as Southwest, American Airlines and United Continental to operate the Boeing 737 Max have expressed their confidence in the device. "We will take all necessary steps to clearly understand all aspects of this accident, working closely with the team conducting the investigation and all appropriate regulatory authorities," says the aircraft manufacturer, of Chicago. In the United States, from flight crew and the passengers refused to embark on this device. The trade union of flight personnel (APFA), a representative of the employees of American Airlines, has requested that teams not be allowed to board the Boeing 737 Max 8 if they felt not to be safe.

The prohibitions of flight of the 737 Max, as decided in many countries are primarily a precaution. They also take into account the fear of some crews to fly on a device with a new system for which they would not have been sufficiently trained. 370 Boeing 737 Max have already been shipped to 47 airlines in the world who have gathered with this device in a total of more than 700,000 hours of volume The punishment of Wall Street for the moment was less violent than expected. The course of Boeing Monday, sold 5, 3%, after initially having plunged 12%. A loss of confidence in the 737 Max would be catastrophic for Boeing. The company consists of 5,000 commands of various versions of this model, which represents two-thirds of its future deliveries and approximately 40% of its profits. To this day Boeing assembles every month 52 copies of its 737 Max, and hopes to bring the rate to 57 by the end of the year.