Ill-equipped to handle increasing traffic and jumbo jets, Los Rodeos (also called Tenerife Norte - TFN) had other potential problems that spring day.
Located near mountains - like Pico de Teide - TFN’s runway could be clear one minute and completely shrouded in clouds the next. The airport had no ground radar. Its air traffic controllers had thick Spanish accents. The center lights weren’t working. And the pilots who were flying into Tenerife were facing long delays, threatening their "legal" flying requirements. Taken together, the events created a potential for disaster.
But there was something more. Jacob van Zanten, the captain of KLM 4805, had spent the last months of his career working with pilots in a flight simulator. Pilots in flight simulators concentrate more on flying planes than communicating with ground control in airport towers.
The deadliest crash in the history of aviation occurred on the ground.