An aerial photo shows Boeing 737 Max planes parked on the tarmac at the Boeing factory in Renton, Wash. (Lindsey Wasson/Reuters)

Transportation Secretary Elaine Chao on Monday added to the host of inquiries touched off by two crashes of Boeing 737 Max jets, saying she is creating an “expert special committee” to review certification procedures for the company’s planes and other aircraft.

The Justice Department’s criminal division is looking into the Max jets, the Transportation Department’s inspector general is investigating the way they were certified, and Congress is planning several hearings, including one Wednesday.

Boeing employees play a major role in the process for certifying that the company’s planes are safe.

After years of advocacy by Boeing and actions by Congress, the Federal Aviation Administrator has been delegating more responsibilities to Boeing and other companies. In 2005, at the direction of Congress, the FAA established a certification system called the Organization Designation Authorization program, which delegates to a Boeing unit much of the work involved with determining whether the company is complying with safety standards.

An FAA funding bill signed by President Trump on Oct. 5 instructed Chao to set up a Safety Oversight and Certification Advisory Committee within 60 days. But it was not until Monday that Chao put out a call to find members. Her “special committee” to examine the Max certification “is being formed within the structure” of that broader advisory committee, Chao said.

“The FAA is working methodically to implement hundreds of provisions within the FAA’s five-year Reauthorization. Those provisions related to safety are receiving our first priority,” including the advisory committee, an FAA spokesman said.

The FAA funding law gave Boeing more power to oversee itself, and the agency has noted that “in recent successive acts, Congress directed FAA to streamline certification, including increased delegation.”

Retired Air Force Gen. Darren McDew, former head of the U.S. Transportation Command, and Capt. Lee Moak, former president of the Air Line Pilots Association, will be interim co-chairmen of the special committee looking into the Boeing Max, the Transportation Department said.

Chao and FAA officials have faced questions about the federal response to the risks posed by software, hardware and training issues connected with Max jets.

Chao last week called for an audit of the certification process, saying that the application had been in the works since January 2012 and that the Max 8 was certified in March 2017, shortly after she took over the department.

Sen. Richard Blumenthal (D-Conn.) called Chao’s audit request “inadequate and incomplete,” and said investigators need to focus on the “FAA’s lackluster response to the safety concerns that were first raised after a Lion Air Boeing 737 MAX 8 crashed in October 2018.”

“Did FAA or Boeing employees engage in any unethical, improper or criminal activity during the certification process?” Blumenthal said in a letter to the inspector general.

An FAA spokesman said the agency “took urgent action in the immediate aftermath of the Lion Air and Ethiopia Airlines accidents, including an emergency airworthiness directive within days,” and has been working with Boeing on a software fix.