On the morning of November 2, 2010, Lion Air Flight 712, operating a Boeing 737-400 with registration PK-LIQ, departed from Soekarno-Hatta International Airport in Jakarta, Indonesia, bound for Pontianak. The domestic flight carried 175 occupants, including passengers and crew. As the aircraft prepared for departure, a yaw damper warning light illuminated on the cockpit panel. Pilots reset the system, but the indicator reactivated, prompting a request for the onboard maintenance technician to inspect the issue. The flight departed with nearly an hour of accumulated delay. [1]
The aircraft, manufactured in 1991, had accumulated 49,107 flight hours and 28,889 cycles. The cockpit was manned by a 42-year-old commander with 8,190 hours of experience acting as pilot flying, and a 26-year-old first officer with 656 hours as pilot monitoring. Prior to takeoff, the crew noted that the thrust reverser lever offered resistance and that the speed brakes did not deploy automatically as expected. These known anomalies were reiterated during the approach briefing for the landing at Supadio Airport. [1]
The incident occurred as the Boeing 737 descended towards Runway 15 at Supadio Airport under rainy conditions. The wet runway, measuring 2,250 meters in length, reduced braking efficiency. During the final approach, the aircraft failed to capture the glide slope initially, causing it to remain high. When the autopilot was disconnected, the commander manually adjusted the descent rate. Simultaneously, the flap configuration became unstable; despite selecting 40 degrees of flaps, the indicators showed only 30 degrees until shortly before touchdown. The flight data recorder revealed that the approach was unsustained from approximately 1,000 feet down to the last 50 feet, with descent rates exceeding 2,500 feet per minute and speeds exceeding the stabilized approach criteria. [1]
Upon landing at approximately 11:18 local time, the aircraft touched down well past the designated touchdown zone. The commander applied maximum manual braking and attempted to deploy the speed brakes manually. However, consistent with previous reports, the speed brakes failed to deploy automatically or manually during the rollout, and the thrust reversers experienced significant resistance. Although the reversers eventually engaged, the lack of aerodynamic drag from the speed brakes and the wet runway conditions severely impaired deceleration. The aircraft overran the end of the 2,250-meter runway, traveling through a 60-meter paved stopway and entering soft ground, where it came to a halt with its nose gear sunk in mud. [1]
The National Transportation Safety Committee (KNKT) of Indonesia conducted the official investigation. Their findings highlighted a combination of procedural and technical failures. The approach was deemed unsustained, violating critical safety limits regarding descent rate and speed relative to the reference landing speed (Vref). Furthermore, the investigation revealed that the speed brake malfunction was not an isolated incident. Between September 3 and October 27, 2010, thirteen separate pilot notifications had documented anomalies with the automatic deployment of the speed brakes. Maintenance records indicated repeated interventions involving the cleaning of electrical connections and relays, but no formal risk assessment had been conducted for this recurring defect. [1]
Flight data analysis showed that significant deceleration did not begin until approximately thirteen seconds after touchdown, during which time the aircraft traveled roughly 611 meters. The KNKT concluded that even with properly functioning reversers and speed brakes, the margin of safety on the wet runway was thin, but the absence of the speed brakes critically increased the stopping distance. The aircraft required a runway length greater than the 2,250 meters available. The loud noise heard during the rollout was not definitively linked to any specific mechanical failure in the final report. [1]
Despite the severe exit-from-runway accident and significant damage to the aircraft, including the nose landing gear and engines, all 175 people aboard evacuated successfully without injury. The aircraft was damaged beyond repair. The KNKT issued recommendations to Lion Air to strictly adhere to manufacturer maintenance procedures and to enforce crew discipline regarding stabilized approach criteria. The report also highlighted deficiencies in crew resource management, noting a lack of mutual monitoring between the pilots during the critical approach phase. [1]
The accident occurred during a period when many Indonesian airlines, including Lion Air, were banned from operating in the European Union due to safety concerns. Lion Air was removed from the EU blacklist in June 2016. The incident underscored the importance of addressing recurring maintenance warnings proactively. A similar runway overrun occurred at the same airport on February 16, 2019, involving another Lion Air Boeing 737-800 during heavy rain, though this incident resulted in minor injuries. The Flight 712 case reinforced the global push for better runway condition reporting, such as the ICAO Global Reporting Format, and longer flight data recorder audio retention periods. [1]
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