The Federal Aviation Administration on Tuesday outlined a series of changes to the way it reviews aircraft designs, responding to criticism directed at the agency following a pair of Boeing (NYSE:BA) 737 Max crashes that killed more than 300.

The agency is responding to a panel review conducted in January that highlighted areas for improvement. Specifically, the FAA has come under criticism for its practice of giving Boeing and other planemakers responsibility and authority to review design changes.

A Boeing 737 Max on a tug.

Image source: Boeing.

Investigations into the 737 Max crashes have raised questions about Boeing's culture, and put the FAA's processes under a microscope. While there are undoubtably areas for improvement, the FAA's report highlights just how difficult a task the regulator has when reviewing complex new aircraft systems that are constantly being modified.

In the case of the 737 Max, it's the system that was at fault. The plane's MCAS stabilization system was initially reviewed by FAA experts, but later additions and modifications to the system were reviewed and approved in-house by Boeing.

Both the initial report and the FAA's response conclude that it is all but impossible for the FAA to approve every change to every line of software code. Nevertheless, the agency said it will implement changes to the way the in-house approvals are managed and overseen and to "systemically address any actual undue pressure" on engineers to cut corners.

It's also hard for the FAA to act unilaterally, given the global nature of the aircraft business and the airlines to which Boeing and other planemakers sell. The agency said that many of the changes it is seeking to make in the review process will require coordination with international partners.

"International engagement and collaboration are integral to these themes and recommendations, given the global nature of industry and aviation safety," the agency wrote. "We must improve the sharing of knowledge and information to advance global aviation safety. In addition to regular dialogue, we will work with international partners to better understand human factors from a global framework and develop comprehensive standards and means of compliance."