FAA Issues Updated Equipment Rules for Boeing’s 737 Max Jet

(Bloomberg) -- In a small step toward returning Boeing Co.'s 737 Max to service, U.S. regulators are revising requirements for how airlines must operate the plane if equipment breaks down.

The U.S. Federal Aviation Administration on Thursday issued proposed new rules for airline operations on the Max that adapt to the fixes being finalized for the grounded jetliner. The public has 30 days to comment on the document, which was posted on the FAA's website.

Boeing is finalizing changes to a flight-control system linked to two crashes, in Indonesia and Ethiopia, that killed 346 people. The manufacturer is also altering the plane's flight-control computers after tests showed they were vulnerable to failure.

The company must complete an audit of the software changes and test the revised system in flight simulators with a variety of pilots. In addition to signing off on the redesign, the FAA is devising new pilot training.

One of the more technical steps in the process is to revise what's known as the Master Minimum Equipment List, which lays out conditions under which an operator can fly the aircraft with a variety of malfunctions. Major breakdowns require that a plane get fixed before flight, but airlines can fly with relatively minor malfunctions if there are adequate backups and repairs are performed within a prescribed time.

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Previously, airlines operating the Max were allowed to fly in limited circumstances with just one of the plane's two flight-control computers functioning. Each computer contains its own backup system, so FAA concluded it wasn't a safety hazard to fly with only one for brief periods.

However, Boeing is changing the computer software so that in the future each of the two computers will be constantly monitoring the other. The changes will create greater redundancy for the plane, which was adapted from earlier versions, making it more in line with newer aircraft.

Because the two computers will rely on each other, airlines shouldn't be allowed to fly the plane without both systems, the FAA concluded, according to a question-and-answer document prepared for family members of victims in the two Max crashes.

“The FAA proposes that both flight control computers be required, which reflects Boeing's new software architecture that requires both computers,” the agency said in the document.

“This is a positive sign of the measured approach for ensuring the safe return to service of the 737 Max and the thorough approach by the FAA in this process,” Boeing spokesman Paul Bergman said in an email Thursday night.

It's not clear how the FAA action will affect the timing of the return of the 737 Max to service. Even if the agency approves the software changes Boeing is making, the plane can't fly passengers until the equipment rules are finalized, which won't occur until January at the earliest.

While such decisions by FAA are almost never contentious, it's possible the agency's work could be slowed if it receives numerous dissenting opinions during the public comment period.

To contact the reporter on this story: Alan Levin in Washington at alevin24@bloomberg.net

To contact the editors responsible for this story: Jon Morgan at jmorgan97@bloomberg.net, Elizabeth Wasserman, Ros Krasny

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