"We will fully cooperate in the Department of Transportation's audit announced by Secretary Chao," Boeing said in a statement.
Hours after the DOT said it would seek an audit of the FAA's approval of the plane, President Donald Trump said he picked former Delta Air Lines executive Steve Dickson to lead the FAA. The agency has been without a permanent head since January 2018.
The U.S. last Wednesday joined dozens of other countries in ordering a grounding of the Boeing 737 Max planes.
The DOT certified Boeing's 737 Max 8, a re-engined and more fuel-efficient model of its workhorse jet that's been flying since the 1960s, in March 2017.
The Boeing 737 Max 8 features larger engines than previous models and to address potential in-flight stalls, Boeing added an automatic anti-stall system that points the nose of the plane downward, the way pilots recover from such a position. However, if the sensors that determine if the plane is in a stall receive erroneous data and point the nose down, the consequences could be catastrophic.
Investigators probing the doomed Lion Air crash in Indonesia have indicated that the pilots appeared to be battling the system and the similarities between that crash and the Ethiopian Airlines crash have increased scrutiny from lawmakers and regulators on Boeing and the FAA on the plane's launch.
Many pilots were not aware the system existed until after the Lion Air crash. For some of them, training consisted of an iPad presentation, less than an hour long, that explained the differences between the Boeing 737 Max plane and older models. The FAA did not mandate simulator training.
More than 370 of Boeing's 737 Max planes are in airlines' fleets worldwide and with more than 4,500 of them on order. Boeing shares rose 0.3 percent Tuesday to close at $373.43.
Read Chao's memo below:
"Safety is the top priority of the Department, and all of us are saddened by the fatalities resulting from the recent accidents involving two Boeing 737-MAX 8 aircraft in Indonesia and Ethiopia. As you know, Boeing requested an amended type certification for this aircraft in January 2012, and the Federal Aviation Administration issued the certification in March 2017.
To help inform the Department's decision making and the public's understanding, and to assist the FAA in ensuring that its safety procedures are implemented effectively, this is to confirm my request that the Office of Inspector General proceed with an audit to compile an objective and detailed factual history of the activities that resulted in the certification of the Boeing 737-MAX 8 aircraft.
Please keep me apprised of the status of your work as it progresses."