On March 10, 2018 Ethiopian Airlines Flight 302 crashed six minutes after take-off, tragically killing all 157 passengers and crew. The flight departed from Addis Ababa Bole International Airport in Ethiopia bound for Jomo Kenyatta International Airport in Nairobi, Kenya. Citizens from at least 32 different countries were on board, and many were employees of the United Nations who were travelling to Kenya to participate in an environmental conference.
Shortly after take-off the pilot reported a problem and requested to return to the airport. Early reports indicate that the flight crew was experiencing problems with airspeed indicators, and radar data suggests that the aircraft suffered wide fluctuations in vertical airspeed.
The Digital Flight Data Recorder (“DFDR”) and the Cockpit Voice Recorder (“CVR”) have been recovered and these “black boxes” will yield significant information regarding the cause of the crash. The DFDR records approximately 1,000 aircraft parameters which will provide valuable information concerning what the aircraft was experiencing throughout the duration of the short flight. The CVR records all communication and noises in the cockpit and that too will give investigators insight into the cause of the accident.
This is the second loss of the relatively new Boeing 737 Max 8 series aircraft in the past 5 months. In October, Lion Air Flight 610 crashed shortly after take-off into the Java Sea killing all 189 passengers and crew. Although extremely early in the accident investigations, the two crashes appear to involve eerily similar circumstances. As with Lion Air Flight 610, the flight crew of Ethiopian Airlines Flight 302 experienced difficulty in maintaining the aircraft’s vertical airspeed, and each aircraft entered a steep dive causing it to crash. Given these similarities, early focus of the investigation will be on the 737 Max 8’s automatic system designed to prevent the aircraft from entering an aerodynamic stall. The system, not found on predecessor 737 models, is known as the Maneuvering Characteristics Augmentation System or M.C.A.S. The system works in conjunction with Angle of Attack sensors located in the fuselage of the aircraft. These sensors measure the angle of the aircraft in relation to the air that comes across it. If these sensors indicate that the angle of attack or AOA is too high, they will transmit this information to the M.C.A.S. which will cause the forward edge stabilizers located on the aircraft’s tail to push up thereby forcing the nose of the aircraft downward in an effort to avoid a stall. If the M.C.A.S. did in fact engage as a result of faulty information transmitted by the aircraft’s AOA sensors, erroneously forcing the nose downward, the pilots would have been unable to prevent the aircraft from entering a steep dive.
As a result of information learned from the crash of Lion Air 610, Boeing issued instructions on the manner in which to disengage the system in the event that the M.C.A.S. improperly lowered the nose of the aircraft. The United States Federal Aviation Administration then issued an Airworthiness Directive requiring US-based operators to incorporate the disengagement procedures into its flight training and operations manual in the event of erroneous readings that caused the M.C.A.S. to engage. It is unknown at this time whether these procedures were incorporated into Ethiopian Airlines training and flight manuals, but the airline is considered one of the safest in the world.
It remains to be determined whether the M.C.A.S. played a role in the crash of Ethiopian Airlines Flight 302. If, however, the system did in fact improperly cause the aircraft to enter into a steep dive, Boeing will be required to answer numerous questions regarding why this supposedly enhanced safety system known as the M.C.A.S. has caused two crashes and the tragic loss of life. Indeed, certain countries, including China and Indonesia, have grounded the 737 Max 8 fleet until additional information is learned from the crash and it is determined whether this model aircraft suffers from a fatal design flaw. As more information becomes available, we will provide further updates.