Incident Overview
On 23 July 2008, a Boeing 737-400 aircraft, registered PK-GZN, operated by PT. Garuda Indonesia, was conducting a scheduled passenger flight from Soekarno–Hatta Airport, Jakarta to Syamsudin Noor Airport, Banjarmasin, Kalimantan. The aircraft carried 121 persons: two pilots, five flight attendants, and 114 passengers including one child and two infants.
According to pilot reports, the landing touchdown was normal. As the aircraft decelerated to about 60 knots, the pilot in command (PIC) applied manual braking. Shortly thereafter, the ANTI SKID INOP light illuminated. The PIC executed the standard memory items from the Emergency Check List and continued taxiing toward the apron. While turning the aircraft right to enter taxiway B, the PIC heard a sound he associated with a tire bursting and stopped the aircraft.
Engineers inspected the aircraft on the apron before passengers disembarked. They informed the PIC that the number-one main landing gear axle had broken and detached from its strut. Additionally, the number-two tire had burst. None of the aircraft’s occupants were injured, and they disembarked normally using airstairs.
Investigation Findings
The National Transportation Safety Committee (NTSC) investigation determined that an undetected fatigue crack in the number-one main landing gear axle had originated from a corroded hole in the brake assembly attachment flange. The fatigue crack propagated toward the flange and the axle wall, reaching a length of about 6 cm before a fast final fracture occurred.
No other contributing factors were identified in the source report. The aircraft’s flight recorders, meteorological conditions, and other systems were noted but not implicated.
Actions Taken
On 5 August 2008, the operator’s maintenance organization issued engineering orders requiring increased inspection schedules for Boeing 737 main landing gear axles, because the axle had failed at a time significantly short of the manufacturer’s specified component life.
On 6 August 2008, the NTSC issued recommendations to the Directorate General of Civil Aviation, the US Federal Aviation Administration, the Boeing Company, and the European Aviation Safety Agency, with respect to reviewing the overhaul and inspection requirements for Boeing 737 main landing gear axles.
Probable Cause
The investigation concluded that the cause was a fatigue crack that propagated from a corroded hole in the brake assembly attachment flange, leading to fracture of the number-one main landing gear axle.