The Federal Aviation Administration’s top safety manager, facing his most rigorous public questioning since two Boeing jets crashed under similar circumstances, repeatedly defended the FAA’s approach to safety Wednesday but also acknowledged a key agency misjudgment.

Ali Bahrami, the FAA’s associate administrator for aviation safety, sought to blunt criticisms during a Senate hearing that the agency had given Boeing too much power to oversee the safety of the planes it builds. He called the FAA’s system giving companies far-reaching oversight of their own technical work “sound.” The approach allowed the FAA to focus on improving overall safety systems, he said.

Bahrami also conceded that the FAA had misjudged the risk of a second disaster coming so quickly.

Two crashes of new Boeing 737 Max jets within five months in Indonesia and Ethiopia have brought new scrutiny to FAA practices. Certification of the Max specifically, and airplanes in general, remain the subject of ongoing probes.

“We have relied on the industry more than we should . . . to do the job that we should do to make sure the American public is safe,” said Sen. Joe Manchin III (D-W.Va.), who is a pilot, at Wednesday’s hearing.

Bahrami previously served as vice president of the Aerospace Industries Association, and before that was a longtime FAA manager overseeing the certification of airplanes built by Boeing in the Seattle area.

Current and former FAA officials have pointed to Bahrami as a key internal champion of the FAA’s highly delegated approach. The Organization Designation Authorization program gives companies such as Boeing responsibility for much of the detailed, technical work of finding whether government safety standards are being met. Last year, as part of the FAA funding bill, Congress gave Boeing and other firms greater power to oversee themselves under the ODA system.

Carl Burleson, the FAA’s acting deputy administrator, argued that delegation is a critical piece of the U.S. safety record. “It doesn’t mean each decision we’ve made has always been perfect. But I do think the fundamental process of how we went about certifying the Max was sound,” Burleson said.

Critics inside and outside the FAA have pointed to major problems with the certification system.

For the Max, Boeing designed — and the FAA certified the safety of — a flawed automated feature known as the Maneuvering Characteristics Augmentation System (MCAS). Investigators say bad information from an external sensor prompted the MCAS to repeatedly force down the noses of the planes before they crashed, resulting in the deaths of 346 people. Boeing is working on software fixes to address that and a separate potential problem with the flight control computer discovered since the crashes.

Senators pressed Bahrami on why the FAA was not more explicit about the specific dangers of the MCAS feature in an emergency Airworthiness Directive last November. That order said erroneous data could lead to trouble controlling the airplane and “possible impact with terrain.” It ordered airlines to augment 737 Max flight manuals with instructions for how pilots should respond if the plane showed signs of “runaway” controls. Boeing also issued bulletins to customers

Sen. Jack Reed (D-R.I.) said that the FAA order did not include crucial information about the nature of the problem and Boeing’s plans for a software fix.

“The implication was that this pilot change would be sufficient,” Reed said. “That lack of transparency I think is not appropriate.”

Bahrami said that the FAA joins accident investigations to obtain real-time information to help it protect aircraft. As part of that, the FAA agrees not to disclose “any indication [about] what may have gone wrong in that particular case,” he said.

“That is a very delicate balance for us to play. . . . From the safety perspective, we felt strongly what we did was adequate,” Bahrami said. “Based on these reviews that come out, we will definitely make adjustments.”

The emergency order was supposed to be an interim step, Bahrami said. After having discussions with airlines and interpreting data from U.S. and Canadian operators, FAA officials thought they had enough time to work with Boeing on the company’s MCAS improvements, he said.

“Based on our risk assessment, we felt we had sufficient time to be able to do the modification, and get the final fix,” Bahrami said. The risk assessment was first reported by the Wall Street Journal.

Then, the Ethiopian Airlines plane crashed March 10.

Boeing said it “began work on a potential software update shortly after” the October 2018 Indonesia crash. “The safety of everyone flying our airplanes was paramount as the analysis was done and the actions were taken,” the company said.