Lawmakers are pursuing new safety issues with two Boeing jets -- the 737 Max and the 787 Dreamliner -- and questioning how in each case managers at the Federal Aviation Administration (FAA) backed Boeing's contention that there was no cause for concern despite objections from the safety agency's own technical experts.
The revelations, contained in a letter from the leaders of the U.S. House Committee on Transportation and Infrastructure, come a week after they chaired an intense public hearing where Boeing CEO Dennis Muilenburg was grilled about the 737 Max crashes in Indonesia and Ethiopia that killed 346 people.
The letter sent Thursday cites "serious, potentially catastrophic safety concerns raised by FAA technical specialists that FAA management ultimately overruled after Boeing objected."
The issues came to light during the House investigation into the accidents but are unrelated to the two crashes. However, they will add to doubts about the independence of the FAA and its oversight of Boeing.
One issue is how FAA managers agreed during certification of the 737 Max to give Boeing a pass on complying with a safety rule that requires more separation between duplicate sets of cables that control the jet's rudder.
This is to avoid the possibility that shrapnel from an uncontained engine blowout could sever all the cables and render the plane uncontrollable.
The requirement was introduced when such a blowout caused the deadly 1989 crash of a United Airlines DC-10 in Sioux City, Iowa. The 737 has never been brought into line with the requirement, and when Boeing updated to the 737 Max it argued once again that design "changes would be impractical" and expressed concern about the potential impact on "resources and program schedules," according to documents submitted to the FAA.
At least six FAA specialists refused to concur with an agency paper that allowed Boeing to claim compliance "without implementing a design change," and an FAA review panel in January 2017 rejected Boeing's position that design changes were impractical.
Nevertheless, the FAA certified the Max for passenger service in March that year, and three months later the FAA formally upheld the controversial paper and waved aside the concern among its own technical staff.
Dreamliners and lightning