High Quality Content by WIKIPEDIA articles! Adam Air Flight 574 (KI-574) was a scheduled domestic passenger flight operated by Adam Air between the Indonesian cities of Surabaya (SUB) and Manado (MDC) that disappeared near Polewali in Sulawesi on 1 January 2007. The plane, a Boeing 737-4Q8, was ultimately determined to have crashed into the ocean, from which some smaller pieces of wreckage have been recovered. The flight recorders ("black boxes") were retrieved from the ocean on 28 August 2007, while salvage efforts for some larger pieces of wreckage continued. All 102 people on board died. This is the highest death toll of any aviation accident involving a Boeing 737-400. A full national investigation was immediately launched into the disaster, uncovering multiple maintenance issues concerning the airline as a whole, including a large number concerning the aircraft. Another possibility proposed by the families of some of the deceased is that the crash was due to a faulty rudder valve, known to have caused previous accidents and incidents on Boeing 737s. Debris location has indicated that the plane likely struck the ocean intact. The final report, released on 25 March 2008, concluded that the pilots lost control of the aircraft after they became preoccupied with troubleshooting the inertial reference system and inadvertently disconnected the autopilot.