A Senate committee has launched an investigation related to allegations that inadequate training of Federal Aviation Administration safety inspectors caused the agency to improperly evaluate software new to the Boeing 737 Max.

The commerce, science and transportation committee's chair says in a letter to acting FAA administrator Daniel Elwell that evidence suggests the FAA may have known of those training "deficiencies as early as August 2018".

"The committee is led to believe that an FAA investigation into these allegations may be been completed recently," says the letter from Senator Roger Wicker.

Wicker's probe responds to allegations from "whistleblowers" and comes amid several high-level inquiries into the FAA's certification of the now-grounded 737 Max.

"Allegations from these whistleblowers include information that numerous FAA employees, including those involved in the aircraft evaluation group for the Boeing 737 Max, had not received proper training and valid certification," writes Wicker.

Some of those staffers may have participated on a "flight standardisation board" [FSB], which determined 737 Max pilot training requirements, Wicker writes.

The committee seeks to establish if inadequate inspector training caused "improper evaluation" by the FAA of the 737 Max's manoeuvring characteristics augmentation system [MCAS].

Wicker seeks to know whether the FAA was aware of training problems and if it investigated. He also seeks copies of resulting reports.

The FAA declines to comment specifically about the Senate's inquiry, but cites Elwell's recent comments to the Senate committee.

"As the FAA acting administrator Dan Elwell stated in last week’s Senate Commerce Committee hearing, 'In our quest for continuous safety improvement, the FAA welcomes external review of our systems, processes, and recommendations.’"

Boeing did not immediately respond to a request for comment.

The 737 Max has been grounded worldwide since shortly after the March crash of an Ethiopian Airlines 737 Max, which followed the October 2018 crash of a Lion Air aircraft of the same type.

Investigators have said the MCAS system played a role in the Lion Air crash and that the Ethiopian flight showed similarities.

The US House Transportation Committee is also investigating, having asked Boeing and the FAA for 737 Max-related certification records, and the US Department of Transportation's inspector general has launched a review of the FAA's Max certification.

Source: Cirium Dashboard