The Tenerife airport disaster on March 27, 1977, remains the deadliest aviation accident in history, claiming the lives of 583 people. It unfolded on the runway of Los Rodeos Airport (now Tenerife North Airport) in the Canary Islands, Spain, when two Boeing 747 jumbo jets collided in dense fog. The collision involved a KLM flight and a Pan American World Airways (Pan Am) flight, both diverted to Tenerife from nearby Gran Canaria Airport following a bomb explosion that had lef to the closure of the airport. The series of miscommunications, visibility challenges, and procedural failures that led to this tragic accident are studied extensively in aviation safety circles and continue to inform modern safety practices.
Both planes were awaiting clearance to take off from Los Rodeos, an airport that was significantly smaller and less equipped to handle large aircraft than Gran Canaria. The airport was congested, with many diverted planes awaiting departure. Los Rodeos had only one main runway and a parallel taxiway meaning that the main runway had to also be used as a taxiway for departing aircraft which were required to taxi along its length and then perform a 180 degree turn at the end in order to line up for take off. The KLM aircraft had successfully executed this procedure with the Pan Am flight following it down the runway. Its instructions were to taxi along the runway until it reached the third exit, at which point it was supposed to rejoin the parallel taxiway. However, dense fog had rolled in, reducing visibility considerably. This, coupled with the fact that the exits were not clearly marked made it almost impossible for the pilots to see which exit they were at. In addition, the ground controllers could not see the aircraft.
Subsequently, several factors aligned, with tragic consequences. The captain of the KLM aircraft, an experienced officer with an excellent service record, believed he had clearance for immediate take off. However, the tower had not given such clearance. Communications were hampered by overlapping radio transmissions resulting in the Pan Am crew, moving slowly in the fog, being unaware that the KLM plane was accelerating down the runway. For the same reason, the KLM crew was unaware that the Pan Am aircraft was still taxiing on the runway ahead of it.
Tragically, as the KLM aircraft approached full take-off speed, the Pan Am pilots saw the landing lights of the KLM jet heading toward them down the runway. In an effort to avoid the collision, the Pan Am crew attempted to veer off to the side while the KLM captain tried to pull the aircraft up early to clear the plane ahead. Despite their efforts, the KLM’s outer engine on the left side of the aircraft struck the upper fuselage of the Pan Am plane. The early take-off attempt couple with the damage to the engine and wing caused the KLM aircraft to stall and roll resulting in it impacting the runway and bursting into flames, while the Pan Am aircraft, damaged beyond hope, also erupted in flames moments later.
Of the 248 people on board the KLM flight, all perished in the collision and subsequent fire. Of the 396 people on the Pan Am flight, 335 were killed, with the survivors all being saved by the fact that they were seated in the front section of the aircraft.
In the aftermath, investigators identified several key factors that contributed to the disaster. One of the primary issues was miscommunication and confusion between the KLM flight crew, the Pan Am crew, and air traffic control. The use of improper language added another layer of complexity, as the crew and controller both used non-standard terms, increasing the potential for misunderstanding. Critical phrases like “take-off” and “ready for take-off” were used interchangeably and in ways that were not entirely consistent with established aviation protocols.
Visibility issues due to the thick fog further exacerbated the situation. Los Rodeos was not equipped with ground radar, meaning that air traffic controllers had no real-time overview of aircraft positions on the ground. The airport’s lack of adequate infrastructure for handling multiple large aircraft also highlighted the risks associated with diverting numerous planes to a facility unprepared for such operations.
Human error was another significant factor. The KLM captain, an experienced and respected pilot, made the premature decision to initiate take-off without confirmed clearance. His experience and authority may have contributed to a phenomenon known as “authority gradient,” where his co-pilot might have been reluctant to challenge the decision despite their uncertainties. This tragedy underscored the need for rigorous adherence to communication protocols and highlighted the risks of assuming clearance without explicit confirmation.
The Tenerife disaster led to profound changes in the aviation industry, particularly regarding communication protocols and cockpit hierarchy. Aviation authorities introduced standardised terminology to prevent ambiguous language and confusion during critical operations. For instance, phrases like “take-off” are now only used when granting final clearance for departure, and pilots and controllers use “departure” in place of “take-off” until clearance is explicitly given.
Crew Resource Management (CRM), a training programme designed to improve communication and decision-making in cockpits, became widely adopted following the Tenerife disaster. CRM emphasises the importance of all crew members feeling empowered to speak up and question decisions, regardless of rank. This practice has become a standard in aviation and is credited with improving safety and reducing the risk of miscommunication in high-stress situations.
The accident also reinforced the need for technological improvements, particularly the implementation of ground radar at airports. Ground radar allows air traffic controllers to track the precise location of each aircraft on the ground, greatly reducing the likelihood of similar accidents in low-visibility conditions. In modern aviation, airports handling large aircraft are typically equipped with advanced ground radar systems to prevent collisions on runways and taxiways.
The Tenerife disaster stands as a tragic reminder of the importance of clear communication, adherence to protocols, and the need for modern technology in aviation safety. The accident remains the deadliest in aviation history, and the lessons learned from it have since influenced countless safety improvements. Today, the industry continues to prioritise these practices to prevent future tragedies, and the changes brought about by this disaster serve as a lasting tribute to the lives lost on that fateful day.
