NEW YORK (AFP) - On March 12, 2019, Dennis Muilenburg phoned US President Donald Trump for support after European and Chinese regulators grounded the Boeing 737 MAX following an Ethiopian Airlines crash that killed 157 people.
When Muilenburg hung up, the Boeing chief executive thought he had the backing of the US leader. But the next day, Trump announced that Boeing's top-selling plane was ''grounded effective immediately.''
Boeing's entire global fleet of almost 400 MAX planes has stayed out of service ever since, plunging the 103-year-old aerospace giant into the biggest crisis of its history.
The situation has raised questions about Boeing's commitment to safety and corporate culture while also tarnishing the company's image as it continues to compete with archrival Airbus.
The crisis has cost Boeing billions of dollars and spawned numerous investigations by US authorities, as well as a lawsuits from victims' families.
The crisis actually began months earlier on October 29, 2018, when a MAX operated by Indonesian carrier Lion Air plunged into the Java Sea.
''Boeing blamed the pilots immediately in Lion Air, and then bungled the response thereafter,'' said Scott Hamilton of Leeham News, an aviation publication.
''Boeing's stubborn resistance to admit its mistakes – even as those mistakes have delayed the return to operation of 737 MAX planes – are turning this into a disaster for the company and its customers,'' said Jim Hall, former chairman of the US National Transportation Safety Board (NTSB).
Indonesian investigators last week attributed the crash to nine factors, including inadequate pilot training and a poorly designed flight handling system known as the Maneuvering Characteristics Augmentation System (MCAS) that it said wasn't properly certified by US regulators.
''These items were connected to each other. If one of them was not occurring on that day, the accident may not have happened,'' said Nurcahyo Utomo, an investigator with Indonesia's National Transportation Safety Committee.
If the investigation showed Lion Air's pilots to be young and untested, it also revealed them to be in the dark about the MCAS, which was not mentioned in Boeing's flight manual.
The system has also been implicated in the Ethiopian Airlines crash.
The MCAS was developed specifically for the MAX to guard against stalling that could be caused by the plane's heavier engines.
The system was activated shortly after takeoff in both flights based on an incorrect sensor reading. The error stemmed from an angle of attack sensor that was approved for service by Xtra Aerospace, a Florida company that had its repair station certificate revoked by the FAA last week.