The question of oversight came into greater focus after the National Transportation Safety Board said on Tuesday it found evidence that suggested four bolts were missing on a door panel that blew out of a new Alaska Airlines 737 MAX 9 plane at 16,000 feet.

In the wake of the January accident, FAA Administrator Mike Whitaker has begun talking publicly about setting up a non-profit third party entity to potentially help oversee Boeing's quality control.

Whitaker told Congress this week that an outside firm is reviewing a longstanding agency practice of delegating some aircraft certification tasks to Boeing. The FAA must certify new airplanes as safe before they can be delivered to airlines.

Senate Commerce committee chair Maria Cantwell, whose committee oversees aviation, said on Thursday she plans to call Whitaker for a hearing to discuss his idea in the coming months.

"The issue is how do you have the right technical people that really understand the technology and how do you get them in the FAA system, in the oversight system to be on the job now," said Cantwell. Boeing's 737 MAX planes are built in her home state of Washington.

In the U.S. House hearing Tuesday, Whitaker said the FAA "should look at a third party. I think it may be an option where there's a higher level of confidence where we have more direct oversight ability, and where the folks doing certain critical inspections don't have a paycheck that's coming from the manufacturer."

"I think what Whitaker's looking for is an objective group," said U.S. aviation safety expert John Cox, adding that it could work if the FAA were able to fund auditors, for example, to do such inspections.

The FAA, however, cannot afford to do the job on its own. In 2019, it told Congress it would need an additional 10,000 employees that would cost $1.8 billion annually if it were to assume all responsibilities for aircraft certification.

Arjun Garg, a former FAA chief counsel and acting deputy administrator, said the agency likely wouldn't be speaking about the idea in public without having already given it thorough consideration.

He added that experts who specialize in aircraft engineering and manufacturing processes could perform that type of independent review, adding that entities such as the Flight Safety Foundation or Embry-Riddle Aeronautical University, which are well known and well regarded in aviation, could bring rigor and credibility to the task.

Problems with aircraft certification are not new. A December 2021 Senate report found "FAA's certification process suffers from undue pressure on line engineers and production staff."

In 2020, FAA employees reported fearing pressure from Boeing, with one employee saying: "It feels like we are showing up to a knife fight with Nerf weapons."

Former House Transportation and Infrastructure Committee chair Peter DeFazio, who led a massive investigation into two earlier MAX crashes that killed 346 people, is skeptical of the third party idea.

"I know of no such entity ready to step in," he said. If "we have a new independent entity supervising Boeing, then FAA would have to oversee the entity. I think it would be more straightforward to increase the FAA inspection workforce - which has never recovered from the cuts" made 30 years ago, he said.

(Reporting by David Shepardson and Rajesh Kumar Singh; Editing by Chris Sanders and Peter Graff)

By David Shepardson and Rajesh Kumar Singh