The Federal Aviation Administration plans to significantly revamp its oversight of airplane construction this summer after questions were raised about how it manages inspections done by the industry, according to testimony prepared for a Senate subcommittee hearing on Wednesday.

The testimony by Calvin Scovel III, the Transportation Department's inspector general who monitors the FAA and other agencies, said his office has found management weaknesses with a number of the FAA's oversight processes over the years.

The comments come as the agency is under increasing scrutiny for its flight approval of the Boeing 737 Max jet. Two of the jets have crashed in the past six months in Indonesia and Ethiopia with deadly consequences, and investigators are examining the role of flight-control software that Boeing designed to prevent aerodynamic stalls.

FAA oversight and its program to allow manufacturers and airlines to have their own employees do inspections will be examined at Wednesday's hearing by the Senate Commerce Committee's aviation subcommittee.

While the agency has made improvements, it plans by July to develop new evaluation criteria for training and company self-audits, Scovel wrote in his prepared remarks obtained by The Associated Press.

"While revamping FAA's oversight process will be an important step, continued management attention will be key to ensure the agency identifies and monitors the highest-risk areas of aircraft certification," Scovel wrote.

Also in prepared testimony, the acting FAA head defended his agency's certification of the 737 Max and its initial resistance to ground the planes until all other major aviation regulators around the world had done so.

Daniel Elwell, also will say Wednesday that Boeing submitted proposed changes in key flight-control software to its 737 Max jetliner in January. He says the FAA is still reviewing the aircraft manufacturer's plans for the software update and more pilot training. He calls FAA's review "an agency priority."

Elwell's testimony, first reported by the Seattle Times, could renew questions over the FAA's response to safety concerns about the Max aircraft after the deadly Oct. 29 crash in Indonesia and another in Ethiopia on March 10, nearly seven weeks after Elwell says Boeing submitted its proposed changes.

FAA spokesman Gregory Martin said Tuesday that the Boeing submission in January was preliminary, not final. He said the FAA has not received Boeing's completed software improvements.

Boeing is updating software designed to protect against aerodynamic stalls, in which planes can lose lift from the wings and fall from the sky if the nose points too high. A company official provided more details on work to update the flight-control software, which was not part of previous 737 models.

A worker walks next to a Boeing 737 MAX 8 airplane parked at Boeing Field, Thursday, March 14, 2019, in Seattle. Ted S. Warren / AP file

Software designers considered "a broad range" of pilot skills "to ensure that normal airmanship skills are sufficient to control the airplane," said the official, who spoke anonymously because the changes have not been made public.

Investigators in Ethiopia expect to issue a preliminary report this week on a plane crash that killed 157 people. But a final determination of the cause of the accident may take months.

Boeing said the changes will include protection against faulty readings by sensors. Erroneous measurements are suspected of triggering flight problems on the Lion Air jet. Regulators say the Ethiopian Airlines Max jet followed a similar flight path, including erratic climbs and descents before crashing minutes after takeoff, and those similarities were an important part of their decision to ground the roughly 370 Max 8 planes around the world.

The New York Times reported Monday that pilots from five airlines tested current and updated software on a Boeing flight simulator. During a test that recreated conditions on the Lion Air flight, the pilots had less than 40 seconds to override the software before the plane uncontrollably plunged toward the ground, the newspaper said, citing two unidentified people involved in the testing.

Pilots can flip one switch to reverse a move by the software to point the nose down, and they can disable the software by flipping two switches at their knees.

Pilots involved in the simulator testing followed those steps and kept the plane under control using the current anti-stall software, the newspaper reported. The Lion Air pilots, on the other hand, had received little training on the system, and it was only after the plane crashed that Boeing first notified pilots of the system's existence.