What happened
On 27 August 2008, a Boeing 737-200, registration PK-CJG, was operating a scheduled passenger flight from Jakarta to Jambi. While descending through approximately 2,500 feet, the flight crew extended the landing gear and selected flap 15°. Shortly thereafter, the crew observed a low-pressure warning and a zero-quantity indication for hydraulic system A.
Despite the loss of hydraulic pressure, the pilot in command continued the approach to runway 31. During the landing roll, the pilot encountered significant difficulty deploying the thrust reversers, noting the lever felt extremely heavy. While attempting to use manual braking, the aircraft drifted right of the runway centerline. The aircraft eventually exited the runway and came to a stop 120 meters beyond the threshold on a surface 6 meters below the runway level. The excursion resulted in three injuries to farmers working near the airfield, including one fatality and two serious injuries. All 124 passengers and the crew evacuated the aircraft safely.
The investigation
The KNKT examined the flight data recorder, cockpit voice recorder, and wreckage. The investigation focused on the degradation of aircraft systems following the loss of hydraulic system A, which impacts critical deceleration components including brakes, spoilers, speed brakes, flaps, and thrust reversers. Investigators also reviewed the crew's use of the Quick Reference Handbook (QRH) and their adherence to Crew Resource Management (CRM) principles during the non-normal event.
Findings
- The loss of hydraulic system A significantly increased the required landing distance, as the aircraft could not utilize thrust reversers or effective speed brakes.
- The flight crew failed to utilize the QRH to properly assess the consequences of the hydraulic failure or to implement necessary checklists.
- There was a lack of effective Crew Resource Management, as the crew did not engage in a detailed discussion regarding the non-normal situation before deciding to land.
- The crew did not consider performing a missed approach, despite having sufficient altitude to evaluate the situation.
- The aircraft touched down at a speed approximately 27 knots higher than the calculated Vref for the configuration, and the lack of speed brake selection further hindered deceleration.
Safety action
Following the incident, the operator implemented several internal safety measures, including corrective training for flight crews regarding hydraulic failures and passenger evacuation briefings. Additionally, recommendations were made to improve maintenance oversight of hydraulic systems and to analyze runway length limitations for heavy landings in degraded configurations.