KLM Flight 4805 and Pan Am Flight 1736, March 27, 1977 This crash remains the deadliest ever, claiming the lives of 583 people when two 747s collided on a foggy runway on the island of Tenerife in the Canary Islands.

The deadliest aviation accident in history occurred on March 27, 1977, known as the Tenerife Airport Disaster. It involved the collision of two Boeing 747 passenger aircraft, KLM Flight 4805 and Pan Am Flight 1736, on the runway of Los Rodeos Airport (now Tenerife North Airport) in the Canary Islands. A total of 583 people perished in the tragedy. The disaster resulted from a catastrophic "perfect storm" of factors, including dense fog that severely limited visibility, a bomb explosion at a nearby airport that diverted many flights to the smaller Tenerife hub, and critical communication misunderstandings between the KLM cockpit and Air Traffic Control. Specifically, the KLM pilot initiated takeoff without clear clearance while the Pan Am jet was still taxiing on the same runway. This event fundamentally changed the aviation industry, leading to the global standardization of "aviation English" and the implementation of Crew Resource Management (CRM), which emphasizes better communication and decision-making within the cockpit to prevent human error.