The Federal Aviation Administration (FAA) on Monday published its final list of required design changes to the Boeing 737 Max, as well as changes to operation and maintenance procedures and to proposed pilot training, that must be completed for the jet to return to passenger service.
The design changes include new software to limit the flight-control system that caused two Max crashes that killed 346 people, a new cockpit alert to tell pilots if a sensor that initiated those crashes is faulty, as well as the rerouting of some wiring on the planes to forestall a potential similar failure being triggered by an electrical short.
The FAA said it completed all approvals associated with the design changes itself, delegating none of the oversight work to Boeing.
"This thorough review has taken more than 18 months and included the full-time work of more than 40 engineers, inspectors, pilots, and technical support staff," the safety agency said. "The effort represents more than 60,000 FAA hours of review, certification testing, and evaluation of pertinent documents. This has so far included approximately 50 hours of FAA flight or simulator tests and FAA analysis of more than 4,000 hours of company flight and simulator testing."
The publication sets in motion the final steps toward allowing U.S. airlines to fly passengers on the Max again before the end of this year.
The FAA documents will be published in the Federal Register in the coming days, which will start the clock on a 45-day period for public comment, during which airline operators, industry experts and members of the public can provide feedback on the FAA proposal.
After some weeks, the FAA will respond to the comments and issue its final Airworthiness Directive, approving the Max to fly again. That clearance is expected in October. After that, U.S. airlines will take a month or two to modify and test their airplanes and train their pilots.
A separate FAA report that will lay out the minimum training standards for Max pilots is still pending.
Fixing the flaws
The proposed FAA Airworthiness Directive that would reverse the March 2019 grounding of the Boeing jet will require installing new software to correct the flaws in the flight control system -- the Maneuvering Characteristics Augmentation System (MCAS) -- that went wrong on the two Max crash flights in Indonesia and Ethiopia.