An international panel of air safety regulators on Friday harshly criticized the U.S. Federal Aviation Administration's (FAA) review of a safety system on Boeing's 737 Max jet that was later tied to two crashes that killed 346 people. The Joint Authorities Technical Review (JATR) was commissioned by the FAA in April to look into the agency's oversight and approval of the so-called MCAS anti-stall system before the fatal crashes. "The JATR team found that the MCAS was not evaluated as a complete and integrated function in the certification documents that were submitted to the FAA," the 69-page series of findings and recommendations said. "The lack of a unified top-down development and evaluation of the system function and its safety analyses, combined with the extensive and fragmented documentation, made it difficult to assess whether compliance was fully demonstrated."

An aerial photo shows Boeing 737 MAX aircraft at Boeing facilities at the Grant County International Airport in Moses Lake, Washington, September 16, 2019. Lindsey Wasson | Reuters

The report comes as regulators around the world continue to scrutinize proposed software changes and training revisions from Boeing that would eventually the resumption of flights. Boeing's top-selling airplane has been grounded worldwide since a March 10 crash in Ethiopia killed 157 people, five months after a Lion Air 737 Max crashed in Indonesia, killing 189 people on board. Major U.S. airlines — including Southwest Airlines and American Airlines — have pushed back the expected resumption of flights until January. The JATR draft recommendations, obtained by Reuters ahead of its release on Friday, also said the FAA's long-standing practice of delegating "a high level" of certification tasks to manufacturers like Boeing needs significant reform to ensure adequate safety oversight. "With adequate FAA engagement and oversight, the extent of delegation does not in itself compromise safety," the report said. "However, in the B737 Max program, the FAA had inadequate awareness of the MCAS function which, coupled with limited involvement, resulted in an inability of the FAA to provide an independent assessment of the adequacy of the Boeing-proposed certification activities associated with MCAS." The report also questioned FAA's limited staffing to oversee certification tasks it designated to Boeing and said there were an "inadequate number of FAA specialists" involved in the 737 Max certification. It added there were signs that Boeing employees conducting FAA work faced "undue pressure. ..which may be attributed to conflicting priorities and an environment that does not support FAA requirements." FAA Administrator Steve Dickson said in a statement he would look at the panel's recommendations and take appropriate action following the "unvarnished and independent review of the certification of the Boeing 737 Max." Boeing said it had no immediate comment ahead of the report's public release.

MCAS performance under scrutiny