Accident Sequence
A scheduled passenger flight from Jakarta to Pekanbaru and onward to Batam proceeded normally on the first leg. After a 30-minute transit in Pekanbaru, the crew prepared for departure to Batam from Runway 18. The first officer acted as pilot flying. The crew used reduced takeoff power with an assumed temperature of 35°C, while actual temperature was 27°C. During the takeoff roll, the aircraft rotated but did not become airborne. The first officer noticed a warning light for the air conditioning system and felt stick shaker. The pilot in command decided to continue the takeoff, but the aircraft remained on the ground even as speed exceeded the computed V2+15 value. With the runway end approaching, the captain aborted the takeoff, applying reverse thrust, speed brakes, and brakes. The nose dropped hard, causing the left front door to open and galley trolleys to block the cockpit door. The aircraft veered right, left the runway, struck trees, and came to rest 275 meters beyond the runway end. One passenger sustained serious injuries; other passengers had minor injuries. All crew members were uninjured. The aircraft was considered a total loss.
Investigation Findings
The investigation determined that the cockpit voice recorder's area microphone was non-functional, so only radio transmissions were recorded. Flight data recorder (FDR) data showed normal engine operation and a trajectory consistent with an attempted takeoff with zero flaps. The flap system was found to function normally, suggesting the flap selector was not moved to a takeoff position. The crew did not perform the before-takeoff checklist as specified in the Boeing 737-200 Pilot's Handbook. The aural takeoff warning system functioned normally except for its circuit breaker, which had a worn latch that caused it to open, preventing the warning from sounding. The galley trolley safety lock and strap were not functioning properly, causing the trolleys to block the cockpit door upon impact. Escape slides failed to deploy, and several slides lacked expiration or last inspection dates. The engine mounting shear pins functioned correctly, separating the engines from the wings and reducing fire risk.
Probable Cause
The most probable cause of the accident was the improper execution of the takeoff checklist, resulting in the failure to set the flaps for takeoff. A contributing factor was the maintenance failure to identify the real problem with the aural warning circuit breaker, which opened during the accident and prevented the takeoff configuration warning from activating.