Boeing unveils software overhaul to 737 MAX jets to address safety concerns

U.S. top aircraft manufacturer Boeing Company on Wednesday announced a software update designed to fix bugs in the flight control system of its 737 MAX jets that led to two deadly crashes in less than five months.

Boeing said it has updated the anti-stall Maneuvering Characteristics Augmentation System (MCAS) flight control system to provide additional layers of protection for MCAS to avoid reading erroneous data from sensors.

The flight control system will compare inputs from both Angle of Attack (AOA) sensors of the aircraft instead of one, and if there is a disagreement of 5.5 degrees or more with wing flaps retracted, MCAS will not be activated, Boeing explained.

In case of an accident, MCAS will not be allowed to command more stabilizer inputs than can be counteracted by the flight crew, so that pilots will have the ability to override MCAS and manually control the airplane, Boeing said.

The company added that it has produced an updated PC-based training program for all 737 MAX pilots to better understand Operations Manual Bulletin, updated Speed Trim Fail Non-Normal Checklist and revised its Quick Reference Handbook.

The software update included information about MCAS improvements that are key to preventing uncontrollable stall allegedly linked to the air crash of Indonesian Lion Air flight 610 (JT610), which killed all the 189 people aboard a 737 MAX jet last October.

Boeing said the improved software has been "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."

Boeing has been under intense scrutiny from the public and federal regulators amid mounting concerns about the safety of its 737 MAX aircraft, which was involved in an air crash of Ethiopian Airlines flight 302 (ET302) in mid-March, in which all 149 passengers and eight crew members died.

The similarities between JT610 and ET302 crashes have led to a global grounding of all Boeing 737 MAX jets.