March 27, 1977 was a difficult day for the aviation industry. Just after noon, a bomb exploded at the Las Palmas passenger terminal in the Canary Islands. Five large passenger planes were diverted to the Tenerife-Norte Los Rodeos Airport, where they completely covered the taxiway of the one-runway regional airport. Less than five hours later, when the planes were finally given permission to takeoff, two collided on the runway, killing 583, making this the worst accident at the time (and second now only to the September 11, 2001 attacks in the US.)
With the benefit of nearly 40 years of hindsight, it is possible to review the causes of the accident, as well as look at the solutions implemented after this accident, which are still being used in the aviation industry today. First we look at the impact to the goals as a result of this tragedy. The deaths of 583 people (out of a total of 644 on both planes) are an impact to the safety goal. The compensation to families of the victims (paid by the operating company of one of the planes) is an impact to the customer service goal. The property goal was impacted due to the destruction of both the planes, and the labor goal was impacted by the rescue, response, and investigation costs that resulted from the accident.
Beginning with one of the impacted goals, we can ask why questions to diagram the cause-and-effect relationships related to the incident. The deaths of the 583 people onboard were due to the runway collision of two planes. The collision occurred when one plane was taking off on the runway, and the other was taxiing to takeoff position on the same runway (called backtracking).
Backtracking is not common (most airports have separate runways and taxiways), but was necessary in this case because the taxiway was unavailable for taxiing. The taxiway was blocked by the three other large planes parked at the airport. A total of five planes were diverted to Tenerife which, having only one runway and a parallel taxiway, was not built to accommodate this number of planes. There were four turnoffs from the runway to the taxiway; the taxiing plane had been instructed to turn off at the third turn (the first turn that was not blocked by other planes). For unknown reasons, it did not, and the collision resulted between the third and fourth turnoff. (Experts disagree on whether the plane would have been able to successfully make the sharp turn at the third turnoff.)
One plane was attempting takeoff, when it ran into the second plane on the runway. The plane taking off was unaware of the presence of the taxiing plane. There was no ground radar and the airport was under heavy fog cover, so the control tower was relying on positions reported by radio. At the time the taxiing plane reported its position, the first plane was discussing takeoff plans with the control tower, resulting in interference rendering most of the conversation inaudible. The pilot of the plane taking off believed he had clearance, due to confusing communication between the plane and the air traffic control tower. Not only did the flight crews and control tower speak different languages, the word “takeoff” was used during a conversation that was not intended to provide clearance for takeoff. Based on discussions between the pilot and flight crew on the plane taking off have, investigators believed, but were not able to definitively determine, that other crew members may have questioned the clearance for takeoff, but not to the extent that the pilot asked the control tower for clarification or delayed the takeoff.
After the tragedy, the airport was upgraded to include ground radar. Solutions that impacted the entire aviation industry included the use of English as the official control language (to be used when communicating between aircraft and control towers) and also prohibited the use of the word “takeoff” unless approving or revoking takeoff clearance. The potential that action by one of the other crew members could have saved the flights aided in the concept of Crew Resource Management, to ensure that all flight crew members could and would speak up when they had questions related to the safety of the plane.
Though this is by far the runway collision with the greatest impact to human life, runway collisions are still a concern. In 2011, an Airbus A380 clipped the wing of a Bombardier CRJ (see our previous blog). Officials at Los Angeles International Airport (LAX) experienced 21 runway incursions in 2007, after which they redesigned the runways and taxiways so that they wouldn’t intersect, and installed radar-equipped warning lights to provide planes with a visual warning of potential collisions (see our previous blog).
To view the outline, Cause Map and recommended solutions from the Tenerife runway collision of 1977, click on “Download PDF” above. Or, click here to read more.