Boeing Completes MCAS Software Upgrade for its 737 Max Planes

IndraStra Global

Boeing Completes MCAS Software Upgrade for its 737 Max Planes

Boeing Completes MCAS Software Upgrade for its 737 Max Planes

Image Attribute: The file photo of Boeing 737 Max 8 rolling out of the company's Renton factory.

According to the latest press release (May 16, 2019), American aircraft major Boeing has completed development of the updated Maneuvering Characteristics Augmentation System (MCAS) software for the 737 MAX, along with associated simulator testing and the company’s engineering test flight. To date, Boeing has flown the 737 MAX with updated MCAS software for more than 360 hours on 207 flights.

The MCAS was designed by Boeing to activate in manual flight, with the airplane’s flaps up, at an elevated Angle of Attack (AOA). The latest software update to provide additional layers of protection if the AOA sensors provide erroneous data. According to the company's statement which was released on April 17, 2019, the upgraded software was put through hundreds of hours of analysis, laboratory testing, verification in a simulator and two test flights, including an in-flight certification test with Federal Aviation Administration (FAA) representatives on board as observers.

The additional layers of protection include:


  • The flight control system will now compare inputs from both AOA sensors. If the sensors disagree by 5.5 degrees or more with the flaps retracted, MCAS will not activate. An indicator on the flight deck display will alert the pilots.
  • If MCAS is activated in non-normal conditions, it will only provide one input for each elevated AOA event. There are no known or envisioned failure conditions where MCAS will provide multiple inputs.
  • MCAS can never command more stabilizer input that can be counteracted by the flight crew pulling back on the column. The pilots will continue to always have the ability to override MCAS and manually control the airplane.

Boeing engineers have been working on the software update for more than six months — far longer than they expected — having started shortly after the October 29, 2018 crash of a 737 Max 8 operated by Indonesia's Lion Air (Flight JT610). The company is now providing additional information to address FAA requests that include detail on how pilots interact with the airplane controls and displays in different flight scenarios. Once the requests are addressed, Boeing will work with the FAA to schedule its certification test flight and submit final certification documentation which is scheduled for next week (dates are yet not announced).

“With safety as our clear priority, we have completed all of the engineering test flights for the software update and are preparing for the final certification flight,” said Boeing Chairman, President, and Chief Executive Officer Dennis Muilenburg. “We’re committed to providing the FAA and global regulators all the information they need, and to getting it right. We’re making clear and steady progress and are confident that the 737 MAX with updated MCAS software will be one of the safest airplanes ever to fly. The accidents have only intensified our commitment to our values, including safety, quality, and integrity, because we know lives depend on what we do.”

In addition, Boeing has developed enhanced training manuals that are now being reviewed with the FAA, global regulators, and airline customers to support return-to-service and longer-term operations. This includes a series of regional customer conferences being conducted around the world.

According to aviation safety analyst, Todd Curtis (while speaking to BBC) — the FAA was not the only one that Boeing had to satisfy. He said, "You also have other national authorities in Canada and the United Kingdom and in Europe who have said they would like to have their own tests and their own evaluation before certifying this aircraft for flight." He further added, "If the authorities there don't certify the 737 Max, they'll have to avoid that airspace."

Till date, the company has delivered about 370 Max jets around the world, but they have been grounded since mid-March after the initial reports blamed MCAS for the crash Ethiopian Airlines flight ET302. That is causing airlines to cancel flights heading into the busy summer travel season. Boeing has disclosed an initial financial hit of US$ 1 billion to fix the plane, and new Max jets are parked at its Renton factory and elsewhere because deliveries have stopped.