Boeing plans an update to the flight control software system for its troubled 737 Max planes that will prevent it from activating if there is too large a disparity of data coming from aircraft sensors, the company said Wednesday.
The company also plans changes in pilot training. The pilots flying a Lion Air jet that crashed in October, killing 189, were unfamiliar with the system and why it was pushing the plane violently up and down.
Boeing didn't say how soon the change would be implemented. The Federal Aviation Administration has to approve it. In the meantime, hundreds of 737 Max planes have been grounded worldwide.
With the software fix, if a plane's two "angle of attack" sensors disagree by 5.5 degrees or more with wing flaps retracted, the Maneuvering Characteristics Augmentation System, or MCAS, will not activate, according to an overview of the update from Boeing.
Later Wednesday afternoon, federal transportation officials will appear before a Senate subcommittee to discuss federal oversight of U.S. commercial aviation and how to improve safety in light of the recent Ethiopian Airlines crash of a Boeing 737 Max aircraft. The FAA has been criticized for giving Boeing too much control over the 737 Max's certification.
Robert Sumwalt, National Transportation Safety Board chairman, Calvin Scovel, inspector general for the Department of Transportation and Daniel Elwell, acting administrator of the FAA, are all expected to give testimony during the Senate Subcommittee on Aviation and Space hearing, which is set for noon PDT.
Elwell is expected to discuss an overview of the FAA's certification and oversight processes, according to a prepared statement he will give at the hearing.
Some version of the FAA's certification process has been in place for more than 60 years and since 1964, regulations on this process have been under "constant review," Elwell says in the statement. Rules applicable to large transport aircraft such as the Boeing 737 Max have been modified more than 130 times.
Elwell said in the statement that the FAA was "directly involved" in the system safety review of MCAS, which also was implicated the second crash, in March, that killed 157 aboard the Ethiopian Airlines flight.
"The certification process was detailed and thorough, but, as is the case with newly certified products, time yields more data to be applied for continued analysis and improvement," he said in the statement. "As we obtain pertinent information, identify potential risk, or learn of a system failure, we analyze it, we find ways to mitigate the risk, and we require operators to implement the mitigation. And that is what has happened in the case of the 737 Max."
The FAA is still reviewing a proposed MCAS software update submitted for certification in January by Boeing. Testing has included "aerodynamic stall situations and recovery procedures," Elwell said.
