What happened
On November 22, 2019, a Boeing 737-401, registration YV3012, operated by Avior Airlines, was landing on runway 13L at El Dorado International Airport (SKBO) in Bogotá, Colombia. During the landing roll, the aircraft experienced a partial collapse of the right main landing gear.
The structural failure caused the right engine's ventral section to undergo abrasion and resulted in structural damage to the right wing. The collapse also caused a puncture in the right wing's main fuel tank, leading to a fuel spill on the runway. The crew managed to guide the aircraft off the runway onto taxiway A8, where it came to a stop. Airport fire services responded immediately to contain the fuel spill. There were no fatalities and no injuries among the 91 passengers and 8 crew members on board. No evacuation was necessary as the situation was deemed controlled by emergency responders.
The investigation
The GRIAA investigation focused on the mechanical failure of the landing gear assembly. Investigators examined the right main landing gear mechanism, specifically inspecting the T-bolt (TB), the upper drag strut (UDS), and the lower drag strut (LDS).
Technical analysis, which included laboratory findings from Boeing, revealed that the failure originated from the T-bolt. The investigation traced the component's history and identified that the T-bolt's nut, washer, and body had migrated through the diameters of the LDS and the Door Fitting Side Strut (DFST). This migration created a force imbalance that led to the partial collapse of the gear under the aircraft's weight. Furthermore, the investigation looked into the machining process of the T-bolt and the maintenance records regarding Service Bulletin No. 737-32-1501.