A Twin Otter aircraft carrying twelve employees of Arabian Gulf Oil Co/AGOCO and Halliburton Company was on a regular daily oilfield crew-change flight to Tripoli (TIP) departing from Hamada around 07:05. Due to military activities in the area, the crew was instructed to return to Hamada. A thick morning mist precipitated at Hamada, causing the crew to circle the area. While attempting to land, the plane contacted an asphalted pipeline bridge crossing just west of the main concrete runway, resulting in a collision and subsequent fire. The pilot likely mistook the bridge for the runway.A Twin Otter aircraft carrying twelve employees of Arabian Gulf Oil Co/AGOCO and Halliburton Company was on a regular daily oilfield crew-change flight to Tripoli (TIP) departing from Hamada around 07:05. Due to military activities in the area, the crew was instructed to return to Hamada. A thick morning mist precipitated at Hamada, causing the crew to circle the area. While attempting to land, the plane contacted an asphalted pipeline bridge crossing just west of the main concrete runway, resulting in a collision and subsequent fire. The pilot likely mistook the bridge for the runway.