Tenerife: The Deadliest Accident in Aviation History

On 27 March 1977, two Boeing 747s collided on a fog-covered runway at Los Rodeos Airport in Tenerife.

Five hundred and eighty-three people died.

It remains the deadliest accident in the history of civil aviation.

Yet neither aircraft had been scheduled to land there.

KLM Flight 4805 and Pan Am Flight 1736 were both bound for Gran Canaria when a bomb explosion and subsequent security threat closed the airport and forced incoming traffic to divert.

What followed was an extraordinary chain of events.

An overcrowded diversion airport.

A blocked taxiway.

A refuelling delay.

Rapidly deteriorating visibility.

Two Boeing 747s using the same runway for taxiing.

Confusion over a taxiway exit.

Ambiguous radio phraseology.

Overlapping transmissions.

A question from inside the KLM cockpit about whether Pan Am had actually cleared the runway.

And finally, a take-off begun without the required take-off clearance.

Within seconds, two of the world’s largest passenger aircraft were racing towards one another through the fog.

TENERIFE — The Deadliest Accident in Aviation History reconstructs the disaster from the events at Gran Canaria through the collision, survival, investigation and international disagreement that followed.

Drawing upon the official investigative record, Bill Stewart examines not only what happened, but the more difficult question:

How did experienced professional crews, trained air traffic controllers and serviceable aircraft become trapped inside a situation that should never have been possible?

The investigation explores:

• KLM Flight 4805 and Pan Am Flight 1736
• the Gran Canaria bombing and diversion
• congestion at Los Rodeos
• the KLM refuelling decision
• Pan Am’s difficulty identifying the intended taxiway exit
• deteriorating fog and loss of visual situational awareness
• the difference between an ATC route clearance and a take-off clearance
• the critical radio transmissions
• cockpit authority and crew challenge
• the Spanish investigation
• the Dutch response
• the development of stronger aviation phraseology and human-factors training
• Tenerife’s enduring influence on Crew Resource Management

The final operational error was clear.