Separately on Friday, a group of aviation experts from nine countries finished their first meeting to review the FAA's approval of the Max, which has been grounded since mid-March after two crashes killed 346 people.
The crashes sparked criticism of both Boeing and the FAA. The Senate Commerce Committee raised questions last month about training of inspectors who certified the Max.
In a letter and other documents made public Friday, FAA acting administrator Daniel Elwell repeated that those inspectors were fully certified.
However, Ellwell said, 16 of 22 other safety inspectors in Seattle and Long Beach, California, have not completed a formal training course required for their jobs, and 11 aren't qualified for the course because they aren't certified flight instructors.
Elwell said the inspectors had on-the-job training, which was also acceptable to perform some duties. He said the FAA is addressing the "confusion" and will revise its inspector-training requirements by September.
FAA had previously disclosed that a manager who retaliated against an employee who raised the training issues no longer works for the agency.
Elwell was responding to questions by the Senate Commerce Committee.
The Senate committee's chairman, Roger Wicker, R-Miss., said Friday he is glad that the FAA acknowledged the need to reform some of its training policies and procedures.
Wicker said, however, that the FAA response raised issues that his committee will examine. He did not give specifics.
Also, the House aviation subcommittee announced Friday that Elwell and Robert Sumwalt, chairman of the National Transportation Safety Board, will testify at a hearing May 15. Both appeared before the Senate aviation subcommittee on March 27.