MCAS

MCAS is an acronym with several notable uses, most commonly referring to two widely known systems. The first is the Massachusetts Comprehensive Assessment System, a state-wide standardized testing program used in public schools in Massachusetts. MCAS is designed to measure student achievement against state standards, with assessments administered in subjects such as English language arts and mathematics at various grade levels, and science in designated grades. Results are used to gauge school performance, inform policy and improvement efforts, and in some cases influence graduation considerations. Over the years the program has undergone revisions to align with evolving standards and reporting formats.

The second prominent use is the Maneuvering Characteristics Augmentation System, a flight control software developed for the Boeing 737 MAX. MCAS was intended to enhance stall characteristics by automatically adjusting the horizontal stabilizer to push the nose downward when the angle of attack indicated a potential stall. It relied on data from angle-of-attack sensors, and in some circumstances could be activated by erroneous sensor input. MCAS came under intense scrutiny after two fatal accidents: Lion Air Flight 610 in October 2018 and Ethiopian Airlines Flight 302 in March 2019. Investigations noted MCAS as a contributing factor and led to a temporary global grounding of the 737 MAX. Boeing and regulators subsequently implemented software and training changes, including revised MCAS logic, additional sensor inputs, and enhanced pilot procedures, culminating in certification updates and renewed operation of the aircraft.