Airbus A300 B4 TC-ACB Accident at Bagram, Afghanistan

Incident Overview and Flight Details On March 1, 2010, an Airbus A300 B4 operated by ACT Airlines, registered as TC-ACB, was conducting a public cargo flight from Bahrain to Bagram, Afghanistan. During the final approach to runway 21, the crew deployed the landing gear and immediately heard an abnormal noise accompanied by vibrations. The cockpit indicated that only two of the three green landing gear lock lights were illuminated, with the unlit light corresponding to the left main landing gear. Five seconds later, the pressure and level of the green hydraulic system dropped to zero. The crew declared an emergency and requested a low pass to visually inspect the gear. Air traffic controllers observed that the gear appeared to be extended normally. The crew then continued the approach at the minimum authorized speed. During braking, the left main landing gear collapsed backward, causing the aircraft to veer off the runway to the left. The aircraft came to a stop on a strip of land 2,000 meters beyond the runway threshold. All five crew members evacuated the aircraft without significant difficulty. ## Aircraft and Crew Information The aircraft, an Airbus A300 B4 with serial number 121, was first put into service in 1981. At the time of the accident, it had accumulated 25,300 cycles and 46,516 flight hours. The aircraft was powered by two General Electric CF6-50C2 engines. The crew consisted of a 50-year-old Turkish captain with 12,923 total flight hours and 8,000 hours on type, and a 51-year-old Turkish first officer. The aircraft's weight and center of gravity were within the manufacturer's limits. ## Investigation and Probable Cause The investigation was delegated to the French Bureau of Enquiries and Analyses for Civil Aviation Safety (BEA) by the Afghan authorities. The left main landing gear was examined in France under BEA control. The investigation determined that a fatigue crack, likely initiated from a corrosion pit that appeared during a landing gear overhaul, led to the failure of the left main landing gear articulation arm. The exact origin of the corrosion pit could not be clearly identified. However, the investigation highlighted certain deficiencies in the maintenance tasks performed during the general overhaul of the landing gear. The use of the landing gear manufacturer's maintenance documentation requires rigor, experience, and expertise. In this case, difficulties in understanding this documentation may have led to the implementation of incomplete and unsuitable work cards and tracking sheets in the workshop. The left main landing gear articulation arm, referenced as P/N C65381-4 and S/N 408B, had a limited life of 76,600 landings. The maintenance facility, Turkish Technic, did not have the necessary traceability document for the part. Using a method provided by Airbus, the maximum number of cycles since the part's introduction in 1982 until 2008 was estimated at 59,294, and 362 cycles had been accumulated since its return to service in April 2009, confirming the part had not reached its cycle limit.