MCAS: How 737 MAX system gained power and lost safeguards

Extensive interviews with people involved with the program, and a review of proprietary documents, show how Boeing originally designed MCAS as a simple solution with a narrow scope, then altered it late in the plane’s development to expand its power and purpose. Then they agreed not to inform pilots about MCAS in manuals, even though Boeing’s safety analysis expected pilots to be the primary backstop in the event the system went haywire. Another Boeing plane, the KC-46 Air Force tanker, has a software-driven system that similarly moves the stabilizer in a wind-up turn and even has the same MCAS name, though the design is very different.

Source: www.seattletimes.com