The U.S. Transportation Department’s internal watchdog, who’s investigating the Federal Aviation Administration’s certification of Boeing Co. 737 Max jets, will testify next week to a Senate panel evaluating the U.S. government’s oversight of commercial aviation.

Calvin Scovel, the Transportation Department’s inspector general, will testify along with FAA Acting Administrator Daniel Elwell and National Transportation Safety Board Chairman Robert Sumwalt, the Senate Commerce Committee said on its website.

The committee also intends to hear from Boeing executives, pilots and other aviation industry groups in a second hearing in the near future, the panel said.

The March 27 hearing comes after the FAA followed the lead of aviation regulators around the world and grounded the 737 Max family of jets following two crashes of the airliner model under similar circumstances in just five months.

The March 10 crash of an Ethiopian Airlines 737 Max 8 crash, and the subsequent grounding of the jets by the FAA, prompted Transportation Secretary Elaine Chao and House lawmakers to ask Scovel’s office to investigate the certification by the FAA and Boeing that the jets were safe to fly.

Separately, law enforcement investigators from Scovel’s office began probing the FAA’s approval of the 737 Max’s anti-stall countermeasure, shortly after a Lion Air 737 Max crashed on Oct. 29 in Indonesia, Bloomberg has reported.

Next week’s hearing was convened by the transportation panel’s aviation subcommittee, chaired by Texas Republican Senator Ted Cruz.