Fort Worth (USA) (AFP)

Seventy days after the 737 MAX fleet was shut down around the world following the crash of an Ethiopian Airlines-type aircraft that killed 157 people, uncertainty surrounds the return of this 737 Boeing flagship plane.

Where are we in this affair, which plunged the American aircraft manufacturer into an unprecedented crisis?

- Where is the investigation? -

The Ethiopian authorities are continuing their investigation but their preliminary conclusions have for the moment cleared the pilots.

On the other hand, they pointed to the MCAS anti-stall system, software specially designed for the 737 MAX to correct an aerodynamic anomaly related to a heavier engine.

The same MCAS had already been implicated in the accident of the 737 MAX 8 of Lion Air in Indonesia last October 29 having made 189 dead.

- The other investigations -

The US Department of Justice (DoJ) has been conducting a criminal investigation into the development and certification of the 737 MAX since November 2018.

Part of the aircraft's systems, including MCAS, were inspected by Boeing engineers in a procedure called ODA, which was put in place more than a decade ago by the federal agency. Aviation Authority (FAA), government sources told AFP.

The DoJ summoned (subpoena) at the end of November the airlines American Airlines and Southwest, two big customers of the 737 MAX, to provide all communication related to the aircraft.

Engineers working on the 737 MAX have received similar requests, according to sources familiar with the matter.

The Ministry of Transportation (DoT) and the FAA also conduct internal investigations of certification procedures.

The FAA has already concluded that its services have not found it necessary to independently assess the safety of the MCAS, preferring to rely on Boeing's findings, according to a government source.

- What is Boeing's line of defense? -

Boeing continues to repeat that the Ethiopian accident is due to a "chain of events" and not to the single malfunction of MCAS.

He acknowledged, however, that there were flaws in the flight simulator software with which the pilots are trained and which are supposed to reproduce the flight conditions.

- When will the 737 MAX return to the world sky? -

The calendar is still vague. Boeing hoped to lift the ban on theft this summer. The aircraft manufacturer has completed the update of the MCAS.

The FAA still has to declare it admissible and perform a flight test.

In addition to the FAA, other civil aviation authorities must also give the green light to the modified 737 MAX.

Until the accident of Ethiopian Airlines, the regulators, confident in the integrity of their counterparts, aligned themselves with the decision of the authority of origin.

But this so-called equivalence system seems to have shattered, the authorities no longer hiding their differences. For example, Canada has made simulator pilot training a cardinal point, where the United States believes that a simple iPad or computer training is enough for some pilots.

- What can Boeing do? -

Nothing. The aircraft manufacturer no longer has the hand.

It suspended its financial forecasts for the year 2019 as well as deliveries of the 737 MAX, which represented 79.5% of the backlog (5,582 aircraft) as of April 30th. Production was reduced in mid-April to 42 aircraft per month against 52 previously.

Boeing has not yet taken measures affecting employment.

If he does not deliver a plane, Boeing does not record a cash entry because airlines pay when they take possession of the aircraft.

- What is the cost of this crisis? -

It has already cost Boeing $ 1 billion, according to a first estimate, but the bill will climb quite quickly because a large number of airline customers (American Airlines, United Airlines, Southwest, Norwegian, Ryannair, Norwegian Air ...) will ask for compensation for the loss of earnings related to the immobilization of the devices.

Most of them have canceled thousands of scheduled flights on the 737 MAX.

In addition to companies, suppliers and subcontractors such as United Technologies and Spirit Aerosystems are also affected.

Passenger opinion surveys show that the general public is not ready to board a 737 MAX right away.

- What about Justice? -

Families of accident victims of Ethiopian Airlines and Lion Air have lodged a complaint against Boeing in the United States.

Boeing, who has presented "his condolences", refuses to comment on these legal actions.

? 2019 AFP