1977 Tenerife Spain Accident


Before there were proper communications structure and terminology.

On March 27th, 1977 a chain of events occurred that resulted in gross misunderstandings between an air traffic controller and the flight crew of a 747.  This miscommunication and misunderstanding ultimately resulted in the Captain of the 747 starting his take-off run when he was not cleared to do so because of traffic on the runway.  Subsequently, the 747 collided with another 747 that was taxing the opposite direction down the runway.  The resulting collision was the largest aviation accident ever, excluding terrorist acts.

Robert Ginnett, in chapter 3 of Cockpit Resource Management talks about groups in terms of norms, status, authority, roles, and boundaries.  One of the most difficult aspects of analyzing this accident, is understanding how the norms, roles, boundaries, and authority concepts of 1977 differed from those of the present day.  As a flight instructor and commercial pilot I’m fairly well versed in the established roles, authority, norms and boundaries as they apply to aviation in 2004, but how were these ideas different in 1977.  I believe, to truly understand what transpired to cause this accident to occur, one must put on virtual 1977 aviation glasses.

The Spanish and Dutch reports point the finger of responsibility at different roles.  It is my belief that neither report illustrates a clearly accurate cause for this accident, however; both reports make several good points.  I believe the causes of this accident are fivefold.  First, the structure of the communications between both aircraft and the tower were not adequate, and could even be called sloppy.  Second, the ATC procedures used by the tower were sloppy, and the controller perhaps did not have control over the situation.  Third, the captain of the KLM 747 did not go out of his way to research an inquiries by his crew.  Fourth, the PanAm and the controller should have retransmitted and requested a response to their blocked communications.  An finally fifth, I believe the KLM, PanAm, and the controller were all fatigued and suffering from a bad case of get-there-itis; or in the case of the controller, he probably wanted all these aircraft to depart so he could go back to running a quiet field.

The first cause, being the nature of the ATC communications was the single greatest cause of this accident.  By today’s standards, the vocabulary and structure of these transmissions could only be called sloppy and unprofessional, but what about in 1977?  This is why I earlier stated that to understand this accident one would need to look at it from the perspective of aviation in 1977.  Had the crews been using today’s terminology “position and hold” or “cleared for takeoff runway xx” or “negative – you are not cleared for takeoff” then there is little chance this accident would have occurred.  The use of the work “OK” by the tower controller played a huge role in the final seconds – had the controller instead responded “negative do not take-off – hold position” then the accident would have been avoided.  It’s hard to judge the conduct of 1977 aviation professionals using today’s standards, since certainly many of today’s ideas and constructs are based on this particular accident.

The second key issue is the traffic control situation.  Aviation then, just as it is now is a high-stakes game, lots of lives at stake; the controller did not appreciate this idea.  I personally believe having two 747s on the runway at once is a sloppy procedure, and the controller, especially since he could not see the aircraft should have held PanAm on the ramp until KLM was airborne.  There were several indications in the report about the controller possibly watching a ball game.  Whether the controller was watching it or not, this does illustrate the level of professionalism of the controller.

Element three, the KLM captain should have done a better job to research the possibility of the other aircraft on the runway.  The Spanish report paints the KLM captain as a rouge captain with his own agenda that the first and second officers were afraid of.  I very much believe this was not the case.  I do not believe those officers were afraid of him, I believe that rather all three in the cockpit on the KLM aircraft were not aware of what was going on, the FO and SO thought the other guy had it straight, and the FO and SO each didn’t want to be wrong.  They both raised the issue, but because they were unsure they didn’t raise it forcefully enough.  The issue for the FO and SO was actually their own uncertainty, and not fear of the captain.  I think the captain thought he was aware of what was going on.  Basically, all three had a piece of the picture, but none fully understood the situation.  To a certain extent the KLM captain did ignore the concerns of his crew, and should have researched the possibility of the other aircraft further.

The fourth element was the fact that the tower controller and the PanAm aircraft both transmitted a message to the KLM aircraft, neither got a response, and neither chose to retry the transmission.  Blocked communications are a fact of life in aviation, we shouldn’t blame the blocked transmission on the accident as both reports did, but rather on the people who should have transmitted a subsequent message asking for response.  The PanAm crew should have started a conversation with the controller stating “verify KLM is holding in position”, “were still on the runway.”  The controller should have called back to the KLM aircraft and said “verify you’re holding in position.”

The fifth and final element is a combination fatigue and desire to get out of Tenerife, not only for the KLM and PanAm crew, but also for the controller.  The controller probably wanted all these planes to leave so he could go back to running a quiet field.  The KLM and PanAm crews wanted to get to their destination and end the day.  This may have caused the controller to take shortcuts like having 2 planes on the runway at once.  This could have also contributed to the generally sloppy communications that occurred.

This accident, just like many others, illustrates that aviation is an unforgiving business.  It demands the highest level of professionalism and precision, not only in flying and technical skills, but also in communications between people.  Even the most remote possibilities of problems still need to be researched if the possibility would affect the safety of flight.
Wiener, Earl L. et al., (1993). Cockpit Resource Management.  New York, NY: Academic Press.

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