An employee works near a Boeing 737 Max aircraft at Boeing's 737 Max production facility in Renton, Washington, U.S. December 16, 2019.

WASHINGTON — House lawmakers are planning to introduce this month a bill that aims to increase the Federal Aviation Administration's oversight of aircraft, a measure that stems from criticism that regulators gave too much power to Boeing when they approved the plane-maker's 737 Max three years ago.

The 737 Max has been grounded worldwide for nearly a year after two crashes — one in Indonesia in October 2018 and another in Ethiopia in March 2019 — killed all 346 people aboard.

Boeing has faced numerous investigations into the plane's development, including a criminal probe and another by the House Committee on Transportation and Infrastructure, whose chairman, Rep. Peter DeFazio, D-Ore., is introducing the bill with Rep. Rick Larsen, D-Wash., who heads the committee's aviation subcommittee.

The legislation has the potential to bring more scrutiny to future aircraft, such as Boeing's 777X, which it began flight testing in January.

"We are close to proposing legislation but we are not waiting to finish all of our investigation and interviews," DeFazio said in an interview Wednesday.

Boeing came under fire for its development of the plane, which included a flight-control system, known as MCAS, that was later implicated in both deadly crashes. Pilots complained they didn't know the system existed until after the Lion Air crash in Indonesia.

The House committee is still seeking to interview more Boeing employees and "a lot" of communications from the FAA about the Max, DeFazio said. While the investigation will continue on, the findings will inform the proposed legislation.

"There's got to be to be a lot more scrutiny and oversight," he said.

The FAA, for its part, said it has provided more than 37,000 pages of documents related to the 737 Max to the committee and that it plans to disclose other documents "in the near future."

"The FAA has been transparent to an unprecedented degree with the Committee on matters related to the Boeing 737 Max," the agency said in a statement. "In addition, we continue to make FAA personnel available for in-person interviews to answer questions from Committee staff members."

Boeing said in a statement: "Safety is our number one priority, and as members of Congress work on legislation, we are committed to working with them and the FAA to promote aviation safety."

Emails and other messages released by Boeing and lawmakers have revealed employees at the manufacturer boasting about convincing regulators to accept less pilot training and ridiculing the aircraft.

In messages from April 2017, one Boeing employee told another: "This airplane is designed by clowns who in turn are supervised by monkeys."

Others showed employees concerned about training. For example, a Boeing employee asked a colleague in a February 2018 message: "Would you put your family on a MAX simulator-trained aircraft? I wouldn't." His co-worker replied: "No." In the same exchange, one of the employees says, "Our arrogance is our demise."