The Boeing Co. is making progress in developing an updated Maneuvering Characteristics Augmentation System (MCAS) software for its 737 MAX aircraft as it works to correct the apparent cause of two fatal jet crashes in the past six months. Boeing CEO Dennis Muilenburg reported the OEM has completed 96 test flights of the 737 MAX with updated MCAS software for the plane's flight control system.
Specifically, Muilenburg said more than 159 hours of air time had been flown with the updated software, testing various in-flight scenarios to evaluated the software changes in multiple flight conditions. “The software update functioned as designed, and I was impressed by the work and professionalism of our team,” he said.
Additional test and production flights are planned in the coming weeks to demonstrate that all the defects have been identified and met all certification requirements.
The "anti-stall" software was developed to off-set the effect of more fuel-efficient engines adopted for the new version of the 737, but which because of their larger size alter the planes’ aerodynamic behavior. The MCAS software apparently responded to inaccurate flight data and sent the two planes into nose dives that the crews were unable to reverse.
The updated software “will make the 737 MAX even safer by preventing erroneous angle-of-attack sensor readings from triggering the … MCAS, something that initial investigation reports indicate occurred in both MAX accidents, as one link in a longer chain of events," he said.
"We look forward to completing near-term milestones on the path to final certification,” Muilenburg said. He did not indicate any timeframe for completing the tests and installing the revised flight-control software.
Last week Boeing cut production for the entire 737 series by about 20% as it diverts resources to correct the cause of the two crashes, the first involving a Lion Air jet in Indonesia, in October 2018, and the second involving Ethiopian Airlines in March. A total of 346 deaths are listed in the two incidents. Boeing had planned to raise output from 52 to 57 jets/month this summer – but now is producing 42 jets/month.
The 737 MAX fleet has been grounded by airlines and aviation regulators around the world, and Boeing has halted deliveries of the aircraft as it implements the correction. It has taken over 5,000 orders for the twin-engine jets since introducing it in 2011, and 376 have been delivered since the commercial debut in 2017.