DC-3 ZS-BWZ was on a return flight from Paris to Palmietfontein when it departed Wadi Halfa after an intermediate stop. Because of atmospheric problems, the crew wanted to lower the trailing aerial. The Radio Officer encountered some problems and got the Aldis lamp to serve as a light. He then noticed that an extension lamp had fallen and was dangling, touching the de-icer fluid tank. As he picked it up, the lamp burst into flames, spreading under the pilot’s seat. Attempts to extinguish the fire failed, so the co-pilot had to carry out an emergency landing in the desert. PROBABLE CAUSE: “The opinion was formed that the fire started in the left hand side of the pilot’s compartment because of an electric short in the extension lamp, producing sufficient heat to ignite propeller deicing fluid, which, in the absence of evidence to the contrary, the Committee was of opinion must have leaked from the tank behind the Commander’s seat. On available evidence, the crew made all possible efforts to extinguish the fire, but the effectiveness of their actions was nullified by the restricted area of operations and the inaccessibility of the seat of the fire. In view of the direct evidence of a blue flame at the time of the conflagration, there would appear to have been a high percentage of methylted spirits in the deicing fluid. This is confirmed by tests made of deicing fluid taken from other aircraft serviced by the same maintenance organisation which did not conform with specification An-F-13.”