A Sabena Convair CV-240 crashed shortly after takeoff from Frankfurt Airport, Germany, resulting in the loss of all 44 occupants. The aircraft was on a regular service from Frankfurt to Brussels with a stop at Frankfurt, and experienced a loss of engine power shortly after takeoff. The probable cause was a heavy deposit of lead on the sparking plugs, leading to a short circuiting of the plugs during takeoff. The pilot’s decision to continue the takeoff, coupled with the retraction of landing flaps at low speed and altitude, may have contributed to the crash. The investigation did not find evidence of a sudden process of lead coating. The continuous nature of the lead coating process suggests it had been ongoing.A Sabena Convair CV-240 crashed shortly after takeoff from Frankfurt Airport, Germany, resulting in the loss of all 44 occupants. The aircraft was on a regular service from Frankfurt to Brussels with a stop at Frankfurt, and experienced a loss of engine power shortly after takeoff. The probable cause was a heavy deposit of lead on the sparking plugs, leading to a short circuiting of the plugs during takeoff. The pilot’s decision to continue the takeoff, coupled with the retraction of landing flaps at low speed and altitude, may have contributed to the crash. The investigation did not find evidence of a sudden process of lead coating. The continuous nature of the lead coating process suggests it had been ongoing.