Boeing 737 MAX groundings
The Boeing 737 MAX passenger airliner was grounded worldwide between March 2019 and December 2020longer in many jurisdictionsafter 346 people died in two crashes, Lion Air Flight 610 on October 29, 2018, and Ethiopian Airlines Flight 302 on March 10, 2019. The U.S. Federal Aviation Administration (FAA) resisted grounding the aircraft until March 13, 2019, when it received evidence of accident similarities. By then, 51 other regulators had already grounded the plane, and by March 18, 2019, all 387 aircraft in service were grounded. In 2016, FAA approved Boeing's request to remove references to a  new Maneuvering Characteristics Augmentation System (MCAS) from the flight manual. In November 2018, after the Lion Air accident, Boeing instructed pilots to take corrective action in case of a malfunction, when the airplane would enter a series of automated nosedives. Boeing avoided revealing MCAS until pilots requested further explanation. In December 2018, the FAA privately predicted that MCAS could cause 15 crashes over 30 years. In April 2019, the Ethiopian preliminary report stated that the crew had attempted the recovery procedure, and Boeing confirmed that MCAS had activated in both accidents. FAA certification of the MAX was subsequently investigated by  the U.S. Congress and multiple U.S. government agencies, including the Transportation Department, FBI, NTSB, Inspector General and special panels. Engineering reviews uncovered other design problems, unrelated to MCAS, in the flight computers and cockpit displays. The Indonesian NTSC and the Ethiopian ECAA both attributed the crashes to faulty aircraft design and other factors, including maintenance and flight crew actions. Lawmakers investigated Boeing's incentives to minimize training for the new aircraft. The FAA revoked Boeing's authority to issue airworthiness certificates for individual MAX airplanes and fined Boeing for exerting "undue pressure" on its designated aircraft inspectors. In August 2020 , the FAA published requirements for fixing each aircraft and improving pilot training. On November 18, 2020, the FAA ended the 20-month grounding, the longest ever of a U.S. airliner. The accidents and grounding cost Boeing an estimated $20billion in fines, compensation and legal fees, with indirect losses of more than $60 billion from 1,200 cancelled orders. The MAX resumed commercial flights in the U.S. in December 2020, and was recertified in Europe and Canada by January 2021. Accident investigations. ICAO regulations Annex 13, "Aircraft Accident and Incident Investigation", defines which states may participate in investigations. For the  two MAX accidents these are: The participating state or national transportation safety bureaus are the NTSB for the US and the NTSC for Indonesia. Australia and Singapore also offered technical assistance, shortly after the Lion Air accident, regarding data recovery from the new generation flight recorders (FDR). With the exception of Ethiopia, the officially recognized countries are members of the Joint Authorities Technical Review (JATR). Lion Air Flight 610. Preliminary investigations revealed serious flight control problems that traumatized passengers and crew on the aircraft's previous flight, as well as signs of angle-of-attack (AoA) sensor and other instrument  failures on that and previous flights, tied to a design flaw involving the Maneuvering Characteristics Augmentation System (MCAS) of the 737 MAX series. The aircraft maintenance records indicated that the AoA sensor was just replaced before the accident flight. The report tentatively attributed the accident to the erroneous angle-of-attack (AoA) data and automatic nose-down trim commanded by MCAS. The NTSC final report, published on October 23, 2019, was prepared with assistance from the U.S. NTSB. NTSC's investigator Nurcahyo Utomo identified nine factors to the accident, saying: "The nine factors are the root problem; they cannot  be separated. Not one is contributing more than the other. Unlike NTSB reports that identify the primary cause of accidents and then list contributing issues determined to be less significant, Indonesia is following a convention used by many foreign regulators of listing causal factors without ranking them". The final report has been shared with families of Lion Air Flight 610, then published on October 25, 2019. Ethiopian Airlines Flight 302. On March 11, FAA defended the MAX against groundings by issuing a Continued Airworthiness Notice to operators. The initial reports for Flight 302 found that the pilots struggled to control  the airplane in a manner similar to the Lion Air flight 610 crash. On March 13, 2019, the FAA announced that evidence from the crash site and satellite data on Flight 302 suggested that it might have suffered from the same problem as Lion Air Flight 610 in that the jackscrew controlling the pitch of the horizontal stabilizer of the crashed Flight 302, was found to be set in the full "nose down" position, similar to Lion Air Flight 610. This further implicated MCAS as contributory to the crash. Ethiopian Airlines spokesman Biniyam Demssie said that the procedures for disabling  MCAS had just been incorporated into pilot training. "All the pilots flying the MAX received the training after the Indonesia crash," he said. "There was a directive by Boeing, so they took that training." Despite following the procedure, the pilots could not recover. The Ethiopian Civil Aviation Authority (ECAA) led investigations for Flight 302, and the United States Federal Aviation Administration assisted in the investigation. Both flight recorders (voice and data) were recovered from the crash site on March 11, 2019. The French aviation accident investigation agency BEA announced that it would analyze the flight recorders from the flight. BEA  received the flight recorders on March 14, 2019. On March 17, 2019, Dagmawit Moges, Ethiopia's transport minister, announced that the black box had been found and downloaded, and that the preliminary data retrieved from the flight data recorder show a "clear similarity" with those of Lion Air Flight 610 which crashed off Indonesia. Due to this finding, some experts in Indonesia suggested that the NTSC should cooperate with Flight 302's investigation team. Later on the evening, the NTSC offered assistance to Flight 302's investigation team, stating that the committee and the Indonesian Transportation Ministry would send investigators  and representatives from the government to assist with the investigation of the crash. The Ethiopian Civil Aviation Authority published an interim report on March 9, 2020, one day before the March 10 anniversary of the crash. Investigators have tentatively concluded that the crash was caused by the aircraft's design. , the final report has not yet been published. Maneuvering Characteristics Augmentation System. MCAS on the 737 MAX was designed to mimic the pitching behavior of the previous generation of the series, the Boeing 737 NG, by pushing down the aircraft nose from an elevated angle of attack (AoA) by automatically  adjusting the horizontal stabilizer and trim tab. The system was intended to protect pilots from inadvertently flying at too steep an angle, which could result in a stall. Boeing, however, asserted that MCAS was not an anti-stall system, as the media widely reported it to be. Pilot movement of the control column on the MAX did not disable MCAS, unlike an earlier implementation of MCAS on the U.S. Air Force Boeing 767 Tanker. During certification of the MAX, Boeing requested and received permission from the FAA to remove a description of MCAS from the aircraft manual, leaving pilots unaware  of the system when the airplane entered service in 2017. Boeing had also knowingly withheld knowledge, for at least a year before the Lion Air crash, that a system to warn of a possible AoA malfunction did not work as advertised. On November 6, 2018, Boeing published a supplementary service bulletin prompted by the first crash. The bulletin describes warnings triggered by erroneous AoA data could cause the pitch trim system to repeatedly push down the nose of the airplane and referred pilots to a "non-normal runaway trim" procedure as resolution, specifying a narrow window of a few seconds  before the system would reactivate and pitch the nose down again. The FAA issued an emergency airworthiness directive, 2018-23-51, on November 7, 2018, requiring the bulletin's inclusion in the flight manuals, and that pilots immediately review the new information provided. Pilots wanted to know more about the issue, and Boeing responded by publicly naming MCAS for the first time in another message to airlines, noting that MCAS operates "without pilot input." In December 2018, the FAA had privately predicted that 15 MCAS-related accidents could result if the system was not redesigned. Boeing said it would revise  MCAS software by April 2019 to correct any problems. The study was only revealed a year later at the December 2019 House of Representatives hearing. Stephen Dickson, who became FAA administrator during the accident investigations, testified at the hearing about his agency's response after the Lion Air accident, saying "the result was not satisfactory". After the March 2019 crash of Ethiopian Airlines Flight 302, Ethiopian investigators determined that pilots had attempted the recommended recovery procedure. Boeing admitted that MCAS played a role in both accidents by activating when it received faulty data from an exterior AoA sensor. In 2020 , an FAA Airworthiness Directive approved design changes for each MAX aircraft, requiring input from two AoA sensors for MCAS activation, elimination of the system's ability to repeatedly activate, and allowing pilots to override the system if necessary. Boeing also overhauled the computer architecture of the flight controls to provide greater redundancy. For each aircraft, the FAA would issue the airworthiness certificate, without delegation to Boeing, upon completion of an AoA sensor system test and a validation test flight. The FAA also required that all MAX pilots receive MCAS-related training in flight simulators by 2021. Before the accidents, simulator  training on the MAX was not required, because the FAA accepted Boeing's position that the MAX was sufficiently similar to the previous 737 series, the NG. Financial and economic effects. The have had a deep financial effect on the aviation industry and a significant effect on the national economy of the United States. No airline took delivery of the MAX during the groundings. Boeing slowed MAX production to 42 aircraft per month until in January 2020, then halted until the airplane was reapproved by regulators. Boeing suffered directly through increased costs, loss of sales and revenue, loss of reputation , victims litigation, client compensation, decreased credit rating and lowered stock value. In January 2020, the company estimated a loss of $18.4 billion for 2019, and it reported 183 canceled MAX orders for the year. In February 2020, the COVID-19 pandemic and resulting travel bans created further uncertainty for Boeing. In March 2020, news that Boeing was seeking a $60 billion bailout caused a steep drop in its stock price, though Boeing eventually received $17 billion in funds from the coronavirus stimulus. Its extensive supply chain providing aircraft components and flight simulators suffered similar losses, as did the  aircraft services industry, including crew training, the aftermarket and the aviation insurance industry. At the time of the recertification by the FAA in November 2020, Boeing's net orders for the 737 MAX were down by more than 1,000 aircraft, 448 orders canceled and 782 orders removed from the backlog because they are no longer certain enough to rely on; the total estimated direct costs of the MAX groundings were US$20billion and indirect costs over US$60billion. On January 7, 2021, Boeing settled to pay over $2.5 billion after being charged with fraud. Popular culture. In February 2022 , Netflix released "", a documentary about the two plane crashes directed by Rory Kennedy.