On 7 December 1983, a Boeing 727-200 taking off from Madrid in thick fog collided at high speed with a Douglas DC-9 which had failed to follow its departure taxi clearance to the beginning of the same runway. The DC-9 crew did not advise ATC of their uncertain location until asked for their position after non-receipt of an expected position report. The Investigation concluded that flight deck coordination on the DC-9 had been deficient and noted that gross error checks using the aircraft compasses had not been conducted. The airport was without any surface movement radar.