Engine Associates Inc, both engines were sent to the United States for a teardown. During the teardown of both engines, investigators discovered several fractures in the fuel lines of the left engine. The fuel feeder lines had fractured flush, exhibiting shear lips. The primary fuel manifold had bent downwards. The secondary fuel manifold had twisted. Its fuel transfer tube had nearly blocked the flow of the fuel, reducing the diameter of the fuel nozzle. On the right engine, the secondary fuel manifold had collapsed and there were fractures on the primary fuel manifold. The fuel lines of both engines had also fractured and bent on its fittings, the No.5 and No.6 fittings. The AIB wanted a closer examination on the engines. Subsequently, the engines were shipped back to Lagos but Millenium only sent the left engine, while the right engine was not shipped back for unknown reasons. As AIB conducted tests on the left engine, metallurgical analysis on the manifolds revealed that both of the manifolds had been overstressed. Despite the findings, there was no evidence that the fracture had occurred prior to the crash. Combined with the absence of the right engine, the team hit a dead end. They eventually began to shift their attention towards the fuel pumps. Investigators eventually discovered that there was a possibility of a microbial growth in the fuel supply. This was caused by the storage of the fuel, which was exposed under the sun. This exposure might have caused the temperature of the fuel to rise as high as 25° Celsius. Added with the typically high humidity in the tropical climate setting, this eventually promoted fungal growth, which would have led to fuel tank corrosion, fuel filters and fuel pipes obstruction, and erratic indication of the fuel tank. The preliminary fuel sample analysis, however, didn't find any positive contamination on the fuel. But due to the earlier findings of possible microbial contamination, investigators issued a recommendation for Dana Air to conduct a visual inspection for possible fuel contamination and to use biocide treatment for the matter. Apart from the fuel samples, there was also suspicion on a certain flying culture in Dana Air, which was called by the investigators as "peculiar fuel management". According to the investigation, the team discovered that there was a certain flying culture for every Dana Air MD-83 flights, in which during an aircraft's approach to its intended destination,