Part 5/8:
As the plane climbed towards 33,000 feet amid deteriorating conditions, the autopilot was set to maintain a specific rate of climb. However, this became increasingly problematic, as the aircraft was unable to maintain speed. The pilots recognized the struggle but failed to grasp the overall implications of their actions. Increasing the pitch to gain altitude further deteriorated its speed, setting the stage for disaster.
Instead of descending back to the safer cruising altitude of 31,000 feet, which they had previously operated at without issue, the crew continued their risky ascent in icing conditions. After toggling the anti-icing system on and off to manage ice growth, they found themselves unable to escape the downward spiral of aerodynamic limits.