Lion Air Flight JT610 – October 29, 2018

On October 29, 2018, Lion Air Flight JT610, a Boeing 737 MAX 8, tragically crashed into the Java Sea shortly after taking off from Jakarta, Indonesia. All 189 passengers and crew onboard perished in the crash. The aircraft had been en route to Pangkal Pinang but encountered significant control issues just 13 minutes into the flight.

Sequence of Events

The flight took off at 6:20 AM local time from Soekarno-Hatta International Airport in Jakarta. As the plane climbed to an altitude of approximately 5,000 feet, it began to experience erratic altitude fluctuations. The aircraft’s automated system, specifically the Maneuvering Characteristics Augmentation System (MCAS), falsely detected that the aircraft’s angle of attack (AOA) was too high, potentially leading to a stall. The MCAS, designed to automatically lower the nose of the aircraft to prevent a stall, activated, pushing the aircraft into a steep descent.

The pilots made repeated attempts to counteract the MCAS by pulling back on the control yoke and manually adjusting the trim. However, each time they tried to regain control, the MCAS re-engaged, pushing the aircraft’s nose down again. The ongoing battle between the pilots and the automated system lasted for several minutes before the aircraft ultimately plummeted into the sea at high speed.

Contributing Factors to the Crash

The Lion Air JT610 crash was the result of multiple contributing factors:

1. MCAS Activation: The Maneuvering Characteristics Augmentation System was a new feature in the Boeing 737 MAX, designed to automatically push the aircraft’s nose down if the AOA sensor detected a high angle, preventing a stall. However, the system relied on a single AOA sensor, and in this case, the sensor was providing faulty data, which repeatedly triggered the MCAS.

2. Faulty AOA Sensor: The AOA sensor, which measures the angle between the wing and airflow, was providing erroneous readings. This faulty sensor caused the MCAS to misinterpret the aircraft’s status and repeatedly push the nose down.

3. Lack of Pilot Familiarity with MCAS: The pilots were unaware of the full functionality and risks associated with MCAS. Boeing had not adequately communicated the existence of the system or its potential to take over control during flight. As a result, the pilots were not trained on how to disable the system effectively in case of a malfunction.

4. Inadequate Maintenance: Investigations revealed that the aircraft had experienced similar issues on a previous flight the day before. Maintenance crews had attempted to address the problem, but the aircraft was cleared to fly without fully resolving the underlying issues with the AOA sensor and the flight control systems.

5. Flight Crew Response: While the pilots fought valiantly to regain control, the unfamiliarity with the new system and the complexity of the situation overwhelmed their ability to respond in time. Their repeated efforts to pull the nose up were undone each time MCAS re-engaged.

6. Warning Signs: Other pilots had experienced similar issues with MCAS, but these incidents were not widely reported or shared with the broader aviation community. As a result, critical warning signs were missed, and no sufficient corrective action was taken to address the system’s vulnerabilities.

Investigation and Findings

The National Transportation Safety Committee (NTSC) of Indonesia led the investigation, supported by international bodies such as the U.S. National Transportation Safety Board (NTSB) and the Federal Aviation Administration (FAA). The investigation focused on several key areas:

1. Black Box Analysis: Data recovered from the flight data recorder (FDR) and cockpit voice recorder (CVR) revealed that the MCAS system had repeatedly engaged during the flight. The data also showed the pilots’ continuous efforts to counteract the system by pulling back on the controls and manually adjusting the trim.

2. Design Flaws in MCAS: The investigation identified significant design flaws in the MCAS system. The reliance on a single AOA sensor made the system vulnerable to erroneous data, and the lack of adequate safeguards meant that the system could override pilot inputs without sufficient checks.

3. Boeing’s Role: Boeing came under heavy scrutiny for failing to adequately inform airlines and pilots about the existence of MCAS and its potential to cause control issues. The system had not been included in pilot training programs, and its failure modes had not been fully communicated.

4. Regulatory Oversight: The FAA’s certification process for the Boeing 737 MAX was also questioned. The FAA had delegated significant portions of the certification process to Boeing itself, and as a result, the MCAS system was not subjected to the rigorous scrutiny it should have been.

Aftermath and Impact on Aviation

The crash of Lion Air Flight JT610, followed by a similar crash involving Ethiopian Airlines Flight 302 in March 2019, led to the global grounding of the Boeing 737 MAX fleet. These two crashes, which claimed a combined total of 346 lives, exposed serious flaws in both the design of the aircraft and the regulatory processes that allowed it to enter service.

Boeing faced widespread criticism for its handling of the situation, leading to significant financial losses, lawsuits, and a loss of public trust in the company. The 737 MAX remained grounded for nearly two years as Boeing worked to address the issues with MCAS and improve the safety of the aircraft.

Key changes implemented as a result of the investigation included:

1. MCAS Modifications: Boeing made significant changes to the MCAS system, including incorporating input from two AOA sensors instead of one and limiting the system’s ability to override pilot inputs. The system was also redesigned to disengage if there were conflicting sensor readings.

2. Pilot Training: New training requirements were introduced to ensure that all pilots flying the 737 MAX were fully trained on the functionality of MCAS and how to disable it in the event of a malfunction.

3. Regulatory Reforms: The FAA and other global regulatory bodies reviewed and overhauled their certification processes, placing greater emphasis on safety oversight and reducing the reliance on manufacturers to self-certify their aircraft.

Conclusion

The crash of Lion Air Flight JT610 was a devastating event that highlighted the dangers of relying too heavily on automated systems without sufficient pilot training and oversight. The tragedy served as a wake-up call for the aviation industry, leading to major reforms in aircraft design, pilot training, and regulatory processes.

While the 737 MAX has since returned to service, the legacy of the crash continues to shape the way the industry approaches safety, technology, and the critical balance between automation and human control. The lessons learned from Lion Air Flight JT610 will help to ensure that such a tragedy is not repeated and that the highest standards of safety are maintained in the aviation industry.