WASHINGTON (Reuters) - The U.S. Transportation Department said on Monday that a new blue ribbon commission will review how the Federal Aviation Administration certifies new aircraft after two Boeing 737 MAX jets crashed in recent months, killing nearly 350 people.

FILE PHOTO: An American Airlines Boeing 737 MAX 8 flight from Los Angeles lands at Reagan National Airport shortly after an announcement was made by the FAA that the planes were being grounded by the United States over safety issues in Washington, U.S. March 13, 2019. REUTERS/Joshua Roberts

U.S. lawmakers have criticized the Federal Aviation Administration’s (FAA) program that allows Boeing and other manufacturers to oversee the process that ensures air worthiness and other vital safety aspects of new aircraft.

They are expected to ask the FAA about the program that allows companies to perform functions on the FAA’s behalf at a Senate hearing on Wednesday.

Senator Richard Blumenthal, a Democrat, said that program effectively “left the fox guarding the hen house.”

The FAA said on Monday it has “never allowed companies to police themselves or self-certify their aircraft.”

The new panel will initially be co-chaired by retired Air Force General Darren McDew, the former head of the U.S. Transportation Command, and Lee Moak, a former president of the Air Line Pilots Association.

“This review by leading outside experts will help determine if improvements can be made to the FAA aircraft certification process,” Transportation Secretary Elaine Chao said in a statement.

The panel’s findings and recommendations will be presented directly to Chao and the FAA, the Transportation Department said.

Acting FAA chief Dan Elwell, National Transportation Safety Board chairman Robert Sumwalt and Transportation Department inspector general Calvin Scovell will testify before the Senate Commerce Committee panel. They will be limited in what the can say about the recent crashes in Indonesia and Ethiopia that killed 346 people as regulators in the country where they occurred are charged with disclosing details of their probes.

Boeing is working on software and training updates for its best-selling 737 MAX aircraft that it expects to detail as early as Wednesday. The company has orders worth more than $500 billion at list prices.

A 2015 Transportation Department inspector general’s audit said the FAA performed oversight of only 4 percent of personnel conducting certification work on its behalf in one year.

Federal prosecutors, the Transportation Department’s inspector general and lawmakers are investigating the FAA’s certification of the 737 MAX 8 aircraft.

The FAA said on Monday that the 737 MAX certification “followed the agency’s standard process and took approximately five years from start to finish.

The FAA said it received no whistleblower complaints or reports “alleging pressure to speed up 737 Max certification.”