Abstract: At approximately 1:03 a.m. on August 13, 2013, Employee #1, an aircraft maintenance technician, was changing filters on Engine Number 1 on an aircraft at the fan control valve. He was using a portable self-supported 6 ft stepladder to access the upper portion of the engine-pylon. After removing the fasteners (screws), Employee #1 descended the ladder and somehow missed a step on the third rung of the ladder. He fell approximately 4.5 ft onto the ground and sustained several rib fractures and a spine injury. Emergency medical personnel were summoned. Employee #1 was transported to a medical center, where he underwent surgical procedures and was hospitalized for five days. He was hospitalized for another 10 days at a regional medical center in a different location. A coworker, the lead mechanic and Employee #1's supervisor stated that he was given a written procedure to do a task of changing filters, which instructs them to use a platform to access the engine. However, Employee #1 stated that it was a common practice to use a stepladder. Employee #1 stated that at the time of the incident, one of his coworkers was performing the same task on the other side of the same aircraft on Engine Number 2 by using a lift-truck (a platform mounted on the truck) but no other lift truck was available for him to use. Therefore, he decided to use a stepladder. Employee #1 had previously observed one of his coworkers using the same type of ladder for changing filters, when he had assisted him. Employee #1 stated that it was common practice to step and sit on the top cap/platform of the stepladder to access an engine-pylon. The top-capped platform of the stepladder was measured as 21.25 in. by 20.5 in.