Ethiopian Report Shows Pilots and Passengers Suffered Terrifying Ordeal Due to Boeing’s MCAS
The Ethiopian government recently released its preliminary accident report to the public for the March 10, 2019 accident involving Ethiopian Airlines Flight 302. The report included plots of the Flight Data Recorder data and a detailed time history of events including those derived from the Cockpit Voice Recorder (CVR). Review of this data leaves no mystery as to why the Boeing 737 MAX fleet was grounded weeks ago after the data became available to the investigators and parties to the investigation. The 737 MAX is defective and dangerous in its current configuration and this data reveals the horror the Ethiopian pilots and their passengers experienced.
The accident airplane no sooner left the runway than the Captain’s stick shaker activated due to a single failed angle of attack (AOA) sensor on his side. Upon retracting the flaps and turning off the autopilot the Boeing MCAS system began applying nose-down stabilizer trim due to the failed AOA sensor, and the Captain trimmed against it with his electric trim switch. This cycle repeated until the flight crew recognized the symptoms and turned the stab trim switches to the CUTOUT position per Boeing procedures for runaway stabilizer trim. For some reason however, the crew could not get the mechanical stabilizer trim to work and they were left to hold their aft force on the control columns, with the Captain asking the First Officer to help him hold the high forces.
The flight crew eventually turned the electric stabilizer trim back on to try to relieve their control forces and the MCAS once again made nose-down stabilizer trim inputs until hitting the nose-down limit. The pilots couldn’t hold this much nose-up control force as the airplane had accelerated to 340 knots indicated airspeed, its maximum allowable airspeed.
Tragically, the airplane pitched nose-down and entered its fatal dive, accelerating to 500 knots airspeed and reaching -2 g vertical acceleration before impacting the ground at about 40 degrees nose-down pitch attitude and 20 degrees left-wing-down roll attitude. The airplane likely experienced terrifying high speed Mach buffet vibrations and related sounds of high airspeed as it descended towards the ground – a tragic final 20-second scene of emotional pain and suffering for everyone on the airplane.
Boeing failed to employ a proper and safe engineering process for the 737 MAX MCAS design, system safety analysis, and certification. The consequences are beyond horrific for those on board Flight 302, their families and friends, and the entire public who expect safe airline travel, especially from the modern “MAX” version of Boeing’s venerable 737 series. Boeing should and must be held fully accountable for its failures and all damages suffered by these innocent victims and their families.