History of the Flight
On 20 October 2008, a Boeing McDonnell Douglas DC-9-82 aircraft, registration PK-LMS, operated by PT. Wings Abadi Airlines, was conducting a scheduled passenger flight from Jakarta Soekarno–Hatta Airport to Juanda Airport, Surabaya. The aircraft carried 174 occupants: three pilots, four flight attendants, and 167 passengers.
The pilot flying was a candidate first officer under training, while the pilot in command served as instructor and monitoring pilot. A qualified first officer occupied the jump seat in the cockpit. The flight was the first sector of the day for the crew.
During the descent to Surabaya, visual meteorological conditions prevailed with a temperature of 34°C. The crew received air traffic control instructions to proceed direct to waypoint NIMAS for an Instrument Landing System approach. The copilot disengaged the autopilot at 1,000 feet to practice manual handling. The approach was reported as normal.
As the aircraft touched down, the crew of another aircraft holding at a runway intersection observed a main wheel detach from PK-LMS. The flight crew of PK-LMS taxied the aircraft to the apron. During the transit check, they discovered that the number-two main wheel (left inboard main landing gear) was missing. The wheel was later found on the runway shoulder, on the right side of the runway. No occupants were injured, and all disembarked normally.
Investigation Findings
The investigation revealed that the detachment was caused by worn inner threads on axle number two of the left main landing gear. This wear led to the loss of the axle nut and subsequent separation of the wheel. The strength and tightness of the threaded joint could not be ensured by the tightening torque applied.
Additionally, the electrical power to the aircraft’s flight recorders remained on during the ground inspection immediately following the incident. As a result, all cockpit voice recorder data was overwritten and was unavailable for the investigation.
Safety Recommendations
The National Transportation Safety Committee (NTSC) issued several recommendations. PT. Wings Abadi Airlines was advised to inspect its fleet to verify the serviceability of landing gear axle threads. The airline was also urged to establish procedures requiring flight crew and maintenance personnel to deactivate flight recorder power as soon as practicable after an accident or serious incident. Furthermore, the NTSC recommended that the Directorate General of Civil Aviation ensure that all Indonesian operators have and implement flight recorder deactivation procedures.