Federal Aviation Administration (FAA) safety inspectors who participated in the certification of the Boeing 737 MAX were “fully qualified,” the acting administrator of the agency wrote in response to a U.S. senator’s concerns.

Sen. Roger Wicker, R-Mississippi, chairman of the Senate Commerce, Science and Transportation committee, wrote earlier this week to Daniel Elwell, the FAA head, that the committee had received information from multiple whistleblowers alleging insufficient training and improper certification of FAA safety inspectors. He wrote that his committee was investigating any potential connection to the fatal crashes of two Boeing 737 MAX jets since October.

On Thursday, Elwell responded in a letter to Wicker, saying the FAA investigated concerns raised by an aviation safety inspector who alleged inspectors within the FAA’s Aircraft Evaluation Group did not meet mandatory training requirements.

Those allegations were specific to that group, not to inspectors involved in the Boeing 737 MAX certification, who were “fully qualified for these activities,” Elwell wrote.

The different concerns raised by the inspector were investigated and the allegations, including acts of retaliation, were substantiated and will be remedied as soon as possible, Elwell wrote. A manager found to have retaliated against the inspector is no longer with the FAA, Elwell wrote.

A spokesman in Wicker’s office couldn’t be reached for comment.

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