Hidden Danger (United Airlines 585, USAir 427 and Eastwind Airlines 517) (S04E05)

On March 3, 1991, United Airlines Flight 585, a Boeing 737, is on its final approach when it unexpectedly rolls into a nosedive, crashing within eight seconds and claiming the lives of all 25 individuals aboard. Three years later, on September 8, 1994, USAir Flight 427, another Boeing 737, faces a similar fate, rolling and descending rapidly before crashing in thirty seconds, resulting in 132 fatalities. However, on June 9, 1996, Eastwind Airlines Flight 517, also a Boeing 737, encounters the same issue but the crew manages to regain control and land safely. The underlying cause of these incidents was a sudden rudder deflection due to thermal shock affecting the hydraulic control valve.