Less than a week after pushing Boeing to release additional documents tied to the operation of the company’s troubled 737 Max jets, Rep. Peter A. DeFazio, chairman of the House Transportation and Infrastructure Committee, has scheduled a second hearing on the aircraft involved in two fatal crashes in less than five months.

The planes have been grounded since March, following crashes in Indonesia and Ethiopia that killed 346 people. Last month, acting FAA Administrator Daniel K. Elwell and, Robert Sumwalt, chairman of the National Transportation Safety Board, testified before the committee about the steps the FAA would take before allowing the jets to resume service.

At the June 19 hearing, members are scheduled to hear from witnesses representing pilots, flight attendants and the aviation industry. Also scheduled to testify are former FAA administrator Randy Babbitt and Capt. Chesley “Sully” Sullenberger. Representatives from Boeing are not scheduled to appear.

U.S. pilots have been among the most vocal in the wake of the two crashes, questioning why they weren’t told more about an anti-stall system known as MCAS, which investigators say was a factor in both crashes.

Transportation Secretary Elaine 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.

There are multiple investigations into the FAA’s role in certifying Boeing’s newest version of its popular 737 aircraft, and whether Boeing may have played too large a role in the process. Chao has appointed a special review committee to examine the agency’s process and has ordered DOT’s inspector general to conduct his own review.

DeFazio’s committee is conducting a separate investigation and as part of that has created a whistleblower hotline.

Last week, DeFazio (D-Ore.) and Rep. Rick Larsen (D-Wash.), chairman of the subcommittee on aviation, sent letters to Boeing, United Technologies Corp. and the FAA requesting documents related to the aircraft’s angle of attack disagree light, which alerts pilots when readings from the sensors don’t match.

Boeing executives acknowledged that they knew the lights did not work on most planes not long after it began delivering 737 Max jets to customers in 2017, but did not tell the FAA until after the crash of a Lion Air jet off the coast of Indonesia Oct. 29, more than a year later.

“Boeing discussed the status of the AOA Disagree alert with the FAA in the wake of the Lion Air accident,” the company said in a statement. “At that time, Boeing informed the FAA that Boeing engineers had identified the software issue in 2017 and had determined per Boeing’s standard process that the issue did not adversely impact airplane safety or operation.”

The jets have been grounded since March 13, and it is not clear when they will resume flying. American Airlines, one of three U.S. carriers that have the planes in their fleets, announced this week that it was canceling all 737 Max flights through Sept. 3.

Boeing is working with the FAA on software updates and new pilot training aimed at addressing concerns about the operation of the MCAS system, which is unique to the 737 Max. Investigators in both the Lion Air and Ethiopian Airline crashes said the system repeatedly pushed the plane’s noses downward, preventing pilots from regaining control of their aircraft because the system received incorrect information from one of the plane’s angle of attack sensors.