The investigation into the Lion Air Flight 610 disaster continues.  Findings in a preliminary report released by Indonesian crash investigators — in conjunction with the timeline of events as currently understood — might reveal more about the “cause” of the accident.

Boeing released a new automated anti-stall system known as the Maneuvering Characteristics Augmentation System, or MCAS, in their 737 Max 8 aircraft variant — many industry observers and safety experts believe that Boeing did not give pilots adequate information regarding the system and the procedures necessary to override the MCAS in emergency situations.

Understanding the MCAS System and Defective AOA Sensors

The MCAS is an anti-stall system that takes in information from angle-of-attack (AOA) sensors located on the fuselage of the 737 Max 8 aircraft.  The AOA sensors feed the MCAS information regarding airspeed and nose angle.  Given this information, the MCAS detects whether the aircraft is at-risk of stalling, and automatically forces the nose down.

In the Lion Air Flight 610 disaster, purportedly, a defective AOA sensor (or sensors), fed the MCAS incorrect information regarding its airspeed and nose angle causing the MCAS the aircraft to go into a nosedive to counteract a non-existent stall.

Two Sets of Pilots, Same Aircraft, Two Different Outcomes

As the aircraft was being forced downward by MCAS, the pilots operating Lion Air Flight 610 on its final, fatal voyage — Captain Bhavye Suneja and his co-pilot, Harvino — attempted to raise the nose and level off the aircraft by hitting a switch on their control column.  This procedure merely “suspended” operation of the MCAS nosedive.  This push-and-pull between the two pilots and the MCAS lasted over 11 minutes before the aircraft finally plunged into the sea.

Interestingly, the pilots operating the same aircraft on a prior flight encountered similar problems with the AOA sensor followed by a sudden nosedive caused by the MCAS.  In response, however, the captain on that flight evaluated the flight data during the incident and determined that the co-pilot’s readings (on the cockpit instruments), matched a standby system and ultimately determined the standby readings were accurate.  Realizing that there was something interfering with the altitude of the aircraft, the captain on then shut off the aircraft’s trim system, which involves a motor that allows the nose to adjust vertically.  This allowed the prior flight to reach its destination safely.

Currently, it is not known whether Captain Suneja and his co-pilot, Harvino, understood that they could shut off the trim system.  Investigators hope that a recovered cockpit recorder will give a clearer understanding of their procedures after the MCAS kicked in.

Indications of Lax Maintenance and Training

Though these reports make the prior flight crew of Lion Air Flight 610 aircraft appear to be more competent in comparison, further investigations must be conducted to determine if the accident was caused by a mechanical failure, pilot error, lack of training, lack of follow-up on reports of trouble during flights and or failure to follow safety protocols with regard to airworthiness in light of the reported problems by the prior flight crew.

Experienced Aviation Lawyers

Steven C. Marks and the attorneys at Podhurst Orseck have served as lead counsel, appointed court counsel and/or counsel representing victims and families in a number of commercial major airline crashes over the past 30 years. Steve’s experience includes serving as co-lead trial counsel representing the victims of the Silk Air Flight MI185, which crashed into the Musi River in Palember, Indonesia during its flight from Jakarta to Singapore in December 1997.