On June 9, 1996, while operating a passenger flight from Trenton, New Jersey to Richmond, Virginia, the crew of Eastwind Airlines Flight 517 temporarily lost control of their Boeing 737-200 due to a rudder malfunction. The crew were able to regain control and landed the aircraft successfully. One person aboard was injured. Flight 517 was instrumental in resolving the cause of Boeing 737 rudder issues that had previously caused two fatal crashes. Flight 517 was the first flight to experience such rudder issues and land safely, allowing investigators to interview the pilots about their experience and to study the aircraft.
Background
On March 3, 1991, United Airlines Flight 585, a Boeing 737-200, rolled to the right and went into a vertical dive while attempting to land in Colorado Springs, Colorado. The resulting crash killed all 25 people on board. The National Transportation Safety Board conducted a thorough investigation. Although a rudder problem was suspected, the aircraft's rudder components could not be tested or fully evaluated because they were too badly damaged in the crash. As a result, the NTSB was unable to conclusively identify the cause of the crash. On September 8, 1994, USAir Flight 427, a Boeing 737-300, abruptly rolled to the left while on approach to Pittsburgh International Airport in an accident very similar to Flight 585. The resulting crash killed all 132 people on board. The NTSB commenced an investigation into Flight 427, which was ongoing throughout the late 1990s.
Flight 517 departed Trenton without incident and encountered no turbulence or unusual weatheren route to Richmond. While on approach to Richmond International Airport, at an altitude of about MSL, the captain felt a brief "kick" or "bump" on the right rudder pedal. Around the same time, a flight attendant at the rear of the plane heard a thumping noise underneath her. As the plane continued to descend through, the captain suddenly experienced a loss of rudder control and the plane rolled sharply to the right. Attempting to regain control, the captain tried to apply full left rudder, but the rudder controls were stiff and did not respond to his commands. The captain applied left aileron and increased power to the right engine to try to stop the roll. The airplane temporarily stabilized, and then rolled to the right again. The crew performed their emergency checklist and attempted to regain control of the aircraft, and after several seconds they abruptly regained control. The airplane operated normally for the remaining duration of the flight. No damage occurred to the aircraft as a result of the incident. One flight attendant suffered minor injuries. No other passengers or crew aboard Flight 517 were injured.
Investigation and aftermath
The NTSB investigated the incident, with a particular focus on determining whether the events of Flight 517 were related to previous Boeing 737 crashes. During the investigation, the NTSB found that prior to the June 9 incident, flight crews had reported a series of rudder-related events on the incident aircraft, including abnormal "bumps" on the rudder pedals and uncommanded movement of the rudder. Investigators conducted interviews with the pilots of Flight 517, and removed rudder components from the aircraft for examination, which helped to establish the cause of the previous crashes of United Flight 585 and USAir Flight 427. The NTSB determined that all three incidents could only be explained by pilot error or a malfunction of the rudder system, and based partly on post-accident interviews with the Flight 517 pilots, concluded that rudder malfunctions were likely to have caused all three incidents. The NTSB also determined that, unlike the United or USAir accidents, the rudder problem on Flight 517 occurred earlier in the landing process and at a higher speed, which increased airflow over the other control surfaces of the aircraft, allowing the pilots to overcome the rudder-induced roll. N221US was repaired and returned to service with Eastwind Airlines and continued to operate with them until the airline ceased operations in 1999. The aircraft was placed into storage at Indy South Greenwood Airport the same year and was scrapped in 2000.
