Cause of Accident
The collision of two Boeing 747s i.e. KLM Flight 4805 (KLM) and Pan Am Flight 1736 (Pan Am) at Los Rodeos Airport in the 27th of March 1977, was a consequence of a series bad judgments and poor luck. The terrorist bombing of a passenger terminal at Las Palmas Airport led to closure of the airport, and the diversion of considerable traffic to Los Rodeos (Tenerife) Airport with inadequate capacity (notably parking and staff). The congestion led to the routine back taxing, which put the two aircrafts on the runway. Other important causal factors include:
Poor visibility
The rapid deterioration of the weather, resulting into reduced and fluctuating visibility, rendered the crews on both the two planes (as well as the control tower) incapable of seeing one another. The visibility may have been lower than 700ft required for takeoff.
Pilot Duty/Rest Regulations
The applicable rules on duty limits restricted the crew’s duty time, rendering it illegal for captains to extend their crew’s duty time. The time margin available to Captain Veldhuyzen van Zanten was slim, and missing it meant staying in Tenerife for the night, and incurring the airline boarding/accommodation costs. The limits led to, or contributed to:
KLM crew’s decision to refuel (55 tons) in anticipation of fueling-related delays due to heavy traffic at Las Palmas Airport. This, along with the earlier decision to allow passengers to deplane blocked Pan Am from leaving before the fog set in, and even most importantly, increased the landing/takeoff distance.
Captain van Zantem’s anxiety and decision-making, particularly at the prospect of the weather worsening
Human Factors
These included a poor cockpit culture that allowed the captain to disregard the crew’s input. Captain van Zantem’s personal pride/embarrassment at the prospect of failing to return to Amsterdam, making a basic mistake, and being corrected by the first officer may have contributed to his poor decision-making. Further, KLM’s crew’s use of non-standard terminology, and Pan Am’s failure to turnoff at C3 were contributory. It is possible, for instance, that the control tower may have understood the statement by KLM’s cockpit that it was “at takeoff” to mean it was in a takeoff position, as against actually taking off.
Communications
The confusion with Pan Am exit off the runway resulted from a lack of clarity about whether they were to turn off at C3, particularly given the taxiway’s acute angle relative to C4. As KLM began to taxi, the first officer made it known that the aircraft was on the roll, and despite the communication from Pan Am that it was still on the runway, the transmission was barely audible in the KLM cockpit. The simultaneous radio transmissions may have created misunderstanding, particularly, worsened by the KLM and the ground crew’s use of non-standard language and a possibly distracted/anxious pilot.
Reason for the Accident
The cause of the accident was pilot error. Captain van Zantem’s decision to takeoff without proper clearance from the tower, especially without information about whether Pan Am had turned off the runway, was ultimately the most critical mistake that led to the accident. In spite of the first officer’s concern about captain’s application of power to the engines, the then cock pit culture ensured that Due to the poor visibility, KLM could not see Pan Am until after it was too late, and once the airplane came into view, captain van Zantem’s attempt to lift over Pan Am proved fruitless because of the additional weight after refueling.
Prevention of Similar Accidents
The change of the cockpit culture for captains to tolerate and encourage input from the cockpit crew is important to ensure collective decision-making and checking of errors. First officer Klass Mauers may have averted the accident if he had challenged the captain once more, in the same way that the flight engineer may have if they had insisted on clarifying Pan Am’s location. The crew should be able to question the captain’s decisions and make recommendations. Even most importantly, rigorous pilot and ground crew training in simulators to perform emergency maneuvers and condition behavior help enhance situational awareness. Additionally, adoption of common working language for pilots and ground crews should eliminate the use of nonstandard terminologies that are prone to creating misunderstandings. On the other hand, better airport/runway lighting and markings can help avoid mistakes by Pan Am with respect to the turnoff taxiway.
However, it is evident that pilot training and improved cockpit culture can only go so far. Upwards of 325 runway incursions occur in the US a year, of which 25 are considered extremely serious. The large number of people working in airports and on aircrafts, and they are bound to make mistakes, both human and professional, which can cause accidents similar to this one. Notably, fewer than 10% of the US’ airports do not have any form of movement detection technology, and there are simply too many incidents of runway conflicts.
Ultimately, the adoption of technology to track aircraft movements on runways, including a redundant system that gives cockpit crews for them to make the final decisions on whether to use the runway will be the best measure.
Deficiencies
The report is fairly conclusive, particularly since Spanish and Dutch investigators arrived at nearly similar material conclusions. However, while the report points to there being an agreement that pilot error caused the accident and that a number of contributory factors were unavoidable, it adds there were differences in the apportionment of blame. The implications of these differences are not clear in the report, if at all important. Secondly, it is equally unclear whether KLM’s decision to fuel contravened any regulations, and whether regulations existed then and now about fuel amounts and refueling. Lastly, given the fact that US aircrafts fly to different parts of the world, but the report is silent about the technologies used by airports outside the country. With movement detection technology in 90% of US airports, it is clear that runway intrusions are fairly common, and it may have been helpful to include information about the situation in other airports outside the US. Similarly, while the technology that could stop exactly similar accidents is currently being tested, the report ignores factors such as cost, political decision-making and disruptiveness necessary to adopt the new technology.
Aviation Safety Issues
Important safety issues raised in this report include the necessity of standard terminology in communication by both pilots as well as the ground crew. The accident also emphasizes the necessity of close communication between the cockpit and the ground crew. Lastly, while professional discretion is important, the Tenerife accident raised the necessity to narrow it down even further, including through the change of the cockpit culture, to ensure that safety and technical considerations take precedence over economic and personal factors.
References
NOVA. (2014). Tenerife Airport Disaster . Retrieved Jan 22, 2016, from https://www.youtube.com/watch?v=lrPzb_zcLTI&feature=youtu.be
