The Mystery of AirAsia Flight 8501: Why the Stabilized Climb? An Analysis
The disastrous crash of AirAsia flight 8501 on December 28, 2014, remains a deeply troubling mystery in the realm of aviation safety. The complex interplay of maintenance issues, pilot behavior, and inaction ultimately led to this deadly outcome. A critical aspect of the inquiry has been the series of steep climbs the aircraft executed prior to its tragic end. This article delves into the events leading to these climbs and provides an analysis of potential contributing factors.
Key Events Leading to the Crash
On the fateful day, AirAsia flight 8501 faced a series of challenges. The aircraft had experienced recurring issues with its Flight Augmentation Computer (FAC), which were inadequately fixed through maintenance procedures in the previous year. In an attempt to address these recurring faults, the pilots adopted non-standard procedures. Despite these actions, the situation deteriorated, leading to a cascade of inaction and incorrect piloting techniques that culminated in the catastrophic crash. (Bolton, 2017)
Why the Steep Climb?
Analysis of the cockpit voice recordings and various eyewitness accounts has shed light on the precipitating events leading to the aircraft's steep climbs. One notable event was a possible reset of the FAC circuit breakers by the Captain. After this reset, the aircraft initiated a gradual left turn, characterized by a left roll and left yaw. The roll rate reached approximately 3 degrees per minute. Initially, the Second-in-Command (SIC), or the First Officer (CO) as popularly designated, failed to notice the gradual left roll. (Air accidents and incidents database, 2018)
Rate of Roll and the Captain's Notice
Over the next nine minutes, the aircraft continued to roll to the left, reaching a bank angle of about 54 degrees. The Captain, recognizing the significant change in the aircraft's bank, shouted a warning to the SIC. This sudden awareness on the part of the Captain led the SIC to react by pulling the side stick to the right, attempting to recover the aircraft to a wings-level position. (Air accidents and incidents database, 2018)
Aviation Illusions and Pilot Disorientation
In aviation, somatogravic illusion poses a significant risk to pilots, especially during low-visibility conditions. This illusion can cause a pilot to perceive the aircraft's motion and pitch rate differently from what is actually occurring. For the less experienced SIC, this condition likely exacerbated the situation. As he struggled to regain control, the SIC may have been experiencing a nose-down illusion, caused by erratic movements of the aircraft. In an attempt to counteract this perceived motion, he pulled back on his side stick, resulting in a rapid and abrupt pitch-up.
Understanding Somatogravic Illusion
Somatogravic illusion involves an illusion of motion that affects pilots during low visibility and poor instrument conditions. When a plane makes a sudden pitch or roll change, the fluid in the semicircular canals of the inner ear can become misaligned, causing the pilot to feel as if the plane is in a different orientation than it actually is. This misperception can lead to inappropriate reactions, such as pulling the control stick incorrectly, and potentially causing an aircraft upset.
The combination of the SIC's disorientation and the misinterpretation of the flight controls likely contributed to the steep climbs. This emphasizes the critical importance of proper training and familiarization with flight instruments, especially in challenging and less-than-ideal conditions.
Conclusion
The steep climbs in AirAsia flight 8501 prior to its crash were a result of a series of interconnected factors, including maintenance issues, non-standard procedures, and pilot disorientation. The SIC's failure to recognize the aircraft's bank angle and his misinterpretation of the flight controls, potentially influenced by somatogravic illusion, played a significant role in this critical phase of the flight. This incident underscores the need for thorough training, effective communication, and robust maintenance practices in the aviation industry to prevent such tragedies from recurring.