Several Federal Aviation Administration (FAA) experts suggested suspending the Boeing 737 MAX in March 2019 following a second fatal crash and before the agency took any action,according to a report issued on Friday.

Individual engineers recommended “grounding the airplane while the accident was being investigated based on what they perceived as similarities” between two fatal Boeing 737 MAX crashes in Indonesia and Ethiopia, according to a report from the Transportation Department’s Office of Inspector General’s review of emails and interviews with FAA officials.The Seattle (Aircraft Certification Office) and agency headquarters authorities, however, decided against doing so.

The FAA ultimately grounded the MAX on March 13, 2019 and lifted the flight prohibition order in November 2020 after Boeing made a series of software upgrades and training changes.

The crashes in Indonesia and Ethiopia led to a 20-month grounding for the best-selling plane, costing Boeing more than $20 billion and prompting lawmakers to pass sweeping legislation reforming airplane certification.

Boeing declined comment.

The report FAA officials “expressed frustration that foreign civil aviation authorities were grounding the aircraft before they had data that linked the two accidents.”

The report said FAA has not updated the underlying order and related guidance for its post-event risk assessment processes in over a decade and lacks “quantifiable human factors data, such as pilot reactions to non-normal situations.” It also said FAA

engineers “are not all following or receiving the same guidance or training.” It made seven recommendations for improvements for risk assessments and other issues.

The FAA said it agrees with the Inspector General’s recommendations. “We also continue to look for additional opportunities to apply lessons learned from the Boeing 737 MAX’s return to service,” the agency said Friday.

The report also says following the Ethiopian Airlines crash an FAA engineer drafted a preliminary risk analysis for the MAX on March 12, 2019 that “showed a fleet risk for the MAX that was over 13 times” the agency’s recommended guidelines.

“An FAA official noted at the time that the analysis suggested that there was a 25% chance of an accident in 60 days and that there were only ‘a matter of days’ to implement a fix.”

The inspector general added the engineer’s risk analysis was not completed and did not go through managerial review citing a lack of detailed flight data.