Boeing Chief Executive Dennis Muilenburg speaks during a press conference after the annual shareholders meeting at the Field Museum on April 29, 2019 in Chicago, Illinois. Boeing announced earnings fell 21 percent in the first quarter after multiple crashes of the company's bestselling plane the 737 Max. (Photo by Jim Young-Pool/Getty Images)

Boeing CEO Dennis Muilenburg will testify before House lawmakers next month in what will be his first public hearing since two fatal crashes of the company's popular 737 Max jets.

Boeing and the Federal Aviation Administration are facing several investigations and intense scrutiny over the development and approval of the 737 Max two years ago. The planes have been grounded since mid-March after two crashes within five months of one another that claimed 346 lives.

A flight-control system designed to prevent the planes from stalling misfired on both crashed flights: a Lion Air 737 Max in Indonesia last October and an Ethiopian Airlines plane of the same type in March.