Now, what is the Boeing 737 MAX Automatic Stall-Prevention System (MCAS) about?

The Maneuvering Characteristics Augmentation System (MCAS) is a feature on Boeing 737 MAX aircraft intended to prevent stalls in flaps-retracted, low-speed, nose-up flight. The MCAS uses airspeed and other sensor data to compute when a dangerous condition has developed and then trims the aircraft nose down.

While there have been two crashes of MCAS-equipped aircraft (Lion Air and Ethiopian Airlines), in neither case has a final report been issued that implicates the system.

Boeing reaction

Safety is Boeing’s number one priority and we have full confidence in the safety of the 737 MAX. We understand that regulatory agencies and customers have made decisions that they believe are most appropriate for their home markets. We’ll continue to engage with them to ensure they have the information needed to have confidence in operating their fleets. The United States Federal Aviation Administration is not mandating any further action at this time, and based on the information currently available, we do not have any basis to issue new guidance to operators.