Avss Tenerife Accident Report 3q705p

INTRODUCTION Aviation safety is the concern of the whole world. Its importance is unanimously recognized. While air transportation is by far the safest mode of travel, as measured by the ratio between the number of accidents and that of enger/ kilometres, It is susceptible to inherent risks of flight, the use of force, and, more dangerously, terrorist acts. From time to time, when major aviation related accidents or tragic events take place, the whole world is shaken. Consequently, aviation safety has been and will be a matter of vital importance for governments, industry, the academic community and the traveling public. It is also the raison d’être of ICAO, a global, inter-governmental organization which became a specialized agency of the United Nations in 1947. While everyone agrees that aviation safety is important, opinions vary when an attempt is made to define the term “safety”. The Oxford Dictionary defines “safety” as “freedom from danger or risks”. It also means “the state of being protected from or guarded against hurt or injury”. Clearly, if aviation must be free from any dangers or risks, it will not exist at all. Flight is inherently a risky venture, carried out in a hostile environment at great speed. The only way to assure risk-free flight is never to allow the airplane to leave the gate. Accordingly, some commentators tend to link the concept of safety with accident prevention. They consider “safety” as meaning “no (avoidable) accidents”, or more realistically, “as few accidents as possible”. From a micro and operational point of view, this definition is helpful since much of the safety concern is related to accident prevention. From a macro and policy-oriented point of view, “accident prevention” is too tight a straitjacket to coat the much broader policy consideration underlying the safety issues. Aviation safety includes but is not limited to operational flight safety. The tragic events of 11 September 2001, which constituted not only the most serious threat but also unprecedented damage to aviation safety, have conclusively demonstrated that aviation safety goes beyond accident prevention from a technical point of view and extends to more profound political, strategic and legal dimensions. It includes preventive, remedial and punitive measures. Accordingly, safety is not limited to accident prevention, but should be considered in a broader term as risk management. After a period of study, the ICAO Air Navigation Commission defined “aviation safety” as “the state of freedom from unacceptable risk of injury to persons or damage to

aircraft and property”. Risks could be at a lower or higher level. Depending on the risks involved, the scope of the aforementioned management may range from routine suspension of a license of an unqualified pilot to the temporary grounding of all civil aircraft at the time of a crisis. Sometimes, a particular safety standard is very attractive from a technical point of view, but it may not be cost-effective or may even be economically prohibitive to implement. In that case, a careful policy judgement is needed to determine what standard should be imposed. Consequently, aviation safety requires a multidisciplinary approach: technical, economic, managerial, and, obviously for the purposes of the present study, legal

BACKGROUND OF AN ACCIDENT The Tenerife airport disaster was a fatal runway collision between two Boeing 747s on Sunday, March 27, 1977, at Los Rodeos Airport (now Tenerife North Airport) on the Spanish island of Tenerife, one of the Canary. The crash killed 583 people, making it the deadliest accident in aviation history. As a result of the complex interaction of organizational influences, environmental preconditions, and unsafe acts leading up to this aircraft mishap, the disaster at Tenerife has served as a textbook example for reviewing the processes and frameworks used in aviation mishap investigations and accident prevention.

A bomb explosion at Gran Canaria Airport, and the threat of a second bomb, caused many aircraft to be diverted to Los Rodeos Airport. Among them were KLM Flight 4805 and Pan Am Flight 1736 – the two aircraft involved in the accident. At Los Rodeos Airport, air traffic controllers were forced to park many of the airplanes on the taxiway, thereby blocking it. Further complicating the situation, while authorities waited to reopen Gran Canaria, a dense fog developed at Tenerife, greatly reducing visibility. It begins when the KLM flight landed in Tenerife first and its engers were deplaned. The Pan Am flight landed 45 minutes later but its engers remained on board. The airport at Las Palmas reopened 15 minutes later. The Pan Am aircraft was immediately ready to depart for Las Palmas but was parked behind the KLM and could not depart until the KLM aircraft taxied for takeoff. More than two hours ed before the KLM refueled, re-boarded the engers, and was ready for takeoff. Clouds and fog made visibility very poor, as low as 300 meters, so the controllers in the tower and the crews of both aircraft were completely dependent on their radios for information on runway positions. The tower instructed the KLM to taxi down the takeoff runway, turn around, and wait for further instructions. The Pan Am was to follow behind the KLM on the takeoff runway, turn off at taxiway C3, and use a parallel runway for the rest of its taxi. After completing its turn around at the end of the runway, the KLM requested both takeoff and air traffic control’s (ATC) clearance. The first officer of the KLM radioed, “The KLM 4805 is now ready for takeoff and we are awaiting our ATC clearance.” The tower replied with the following ATC clearance, “KLM…you are cleared to line Papa Beacon, climb to…” While the KLM first officer was reading back the ATC clearance to the tower, the KLM captain released the brakes and said, “We gaan” (we go), and began the takeoff roll. After completing the ATC’s read back, the first officer said either, “We are now —eh—taking off” or “We are now at takeoff.” (The tapes of transmission were not clear.)

In a later statement, the tower controller said he understood the first officer’s message to be, “We are at takeoff position.” The controller replied in response, “Okay,” then paused for two seconds and said, “Stand by for takeoff, I will call you.” Meanwhile, in the Pan Am cockpit, the captain remarked that the KLM could possibly interpret the ATC clearance as takeoff clearance. So, immediately after the tower said “okay” and paused, the Pan Am first officer quickly responded, “We are still taxiing down the runway.” This Pan Am message coincided with the end of the tower ’s instructions to the KLM to standby, which in the KLM cockpit caused a strong squeal. Both messages were barely intelligible in the KLM cockpit. The controller then told the Pan Am to report when clear of the runway and the Pan Am replied they would report when clear. In the KLM cockpit, apparently only the flight engineer heard these last two messages leading to the following dialogue: Engineer, “Is hij er neit af-dan?” (Is he not clear, then?) Captain, “Wat zag je?” (What did you say?) Engineer, “Is hij er niet af die Pan American?” (Is he not clear, that Pan American?) Captain: “Jawal.” (Yes) As a result of several misunderstandings, the KLM flight tried to take off while the Pan Am flight was still on the runway. The resulting collision destroyed both aircraft, killing all 248 aboard the KLM flight and 335 of 396 aboard the Pan Am flight. Sixtyone people aboard the Pan Am flight, including the pilots and flight engineer, survived the disaster. As the accident occurred in Spanish territory, Spain was responsible for investigating the accident. Investigators from the Netherlands and the United States also participated. The investigation revealed that the primary cause of the accident was the captain of the KLM flight taking off without clearance from Air Traffic Control (ATC). The investigation specified that the captain did not intentionally take off without clearance; rather he fully believed he had clearance to take off due to misunderstandings between his flight crew and ATC. Dutch investigators placed a greater emphasis on this than their American and Spanish counterparts, but ultimately KLM itted their crew was responsible for the accident, and the airline financially compensated the victims' relatives.

Figure 1 Chronology of accident.

FATALITIES OF THE ACCIDENT Pan Am Flight 1736 Type Name Operator Registration Flight origin Stopover Destination engers Crew

: Boeing 747–121 : Clipper Victor : Pan American World Airways : N736PA : Los Angeles Int'l Airport Los Angeles, United States : John F. Kennedy Int'l Airport New York City, United States : Gran Canaria Airport Canary Islands, Spain : 380 : 16

Fatalities : 335 (326 engers, 9 crew) KLM Flight 4805 Survivors : 61 Type : Boeing 747-206B Name : Rijn ("Rhine") Operator : KLM Royal Dutch Airlines Registration : PH-BUF Flight origin : Schiphol Airport Amsterdam, Netherlands Destination : Gran Canaria Airport Canary Islands, Spain engers : 234 Crew : 14

Fatalities : 248 (all) Survivors : 0 Total Fatalities 583 people PHASE OF THE FLIGHT DURING THE ACCIDENT HAPPEN

Figure 2 Based on figure 2, the phased of flight of the accident happened are at phased pre-flight/taxi and the take-off/initial climb. By following the tower's instructions, the KLM was cleared to taxi the full length of the runway and make a 180° turn to get into take-off position. While the KLM was back taxiing on the runway, the controller asked the flight crew to report when it was ready to copy the ATC clearance. Because the flight crew was performing the checklist, copying this clearance was postponed until the aircraft was in take-off position on Runway 30. Shortly afterward, the Pan Am was instructed to follow the KLM down the same runway, exit it by taking the third exit on their left and then use the parallel taxiway. Initially, the crew was unclear as to whether the controller had told them to take the first or third exit. The crew asked for clarification and the controller responded emphatically by replying: "The third one, sir; one, two, three; third, third one". The crew began the taxi and proceeded to identify the unmarked taxiways using an airport diagram as they reached them. The crew successfully identified the first two taxiways (C-1 and C-2), but their discussion in the cockpit never indicated that they had sighted the third taxiway (C-3), which they had been instructed to use. There were no markings or signs to identify the runway exits and they were in conditions of poor visibility. The Pan Am crew appeared

to remain unsure of their position on the runway until the collision, which occurred near the intersection with the fourth taxiway (C-4). The angle of the third taxiway would have required the plane to perform a turn of approximately 148°, which would lead back toward the still-crowded main apron. At the end of C-3, the Pan Am would have to make another 148° turn in order to continue taxiing towards the start of the runway. Taxiway C-4 would have required two 35° turns. A study carried out by the Air Line Pilots Association after the accident concluded that making the second 148° turn at the end of taxiway C-3 would have been "a practical impossibility". Subsequent performance calculations and taxi tests with a Boeing 747 turning off on an intersection comparable to the C-3 at Tenerife, as part of the Dutch investigation, indicate that in all probability the turns could have been made. The official report from the Spanish authorities explains that the controller instructed the Pan Am aircraft to use the third taxiway because this was the earliest exit that they could take to reach the unobstructed section of the parallel taxiway.

WAS THE ACCIDENT DUE TO HUMAN ERROR/ WEATHER/ DESIGN OR WHAT? EXPLAIN

1. Weather Condition

Tenerife / Los Rodeos airport is at 633 metres (2,077 feet) above sea level, which s for cloud behaviour that differs from that at most other airports. Clouds at 600 m (2,000 ft) above ground level at the nearby coast are at ground level at Los Rodeos / Tenerife North. Drifting clouds of different densities cause wildly varying visibilities, from unhindered at one moment to below the minimums the next. The collision took place in a high density cloud. The Pan Am crew found themselves in poor and rapidly deteriorating visibility almost as soon as they entered the runway. According to the ALPA report, as the Pan Am aircraft taxied to the runway, the visibility was about 500 m (1,600 ft). Shortly after they turned onto the runway it decreased to less than 100 m (330 ft). Meanwhile, the KLM was still in good visibility, but with clouds blowing down the runway towards them. "The KLM aircraft completed its 180 degree turn in relatively clear weather and lined up on Runway 30. The next cloud was some 900 m (3,000 ft) down the runway and moving towards the aircraft at about 12 knots (6 meters per second)".

2. Taxiing and Take-off Preparations

Figure 2 Based on the figure 2, by following the tower's instructions, the KLM was cleared to taxi the full length of the runway and make a 180° turn to get into take-

off position. While the KLM was back taxiing on the runway, the controller asked the flight crew to report when it was ready to copy the ATC clearance. Because the flight crew was performing the checklist, copying this clearance was postponed until the aircraft was in take-off position on Runway 30. Shortly afterward, the Pan Am was instructed to follow the KLM down the same runway, exit it by taking the third exit on their left and then use the parallel taxiway. Initially, the crew was unclear as to whether the controller had told them to take the first or third exit. The crew asked for clarification and the controller responded emphatically by replying: "The third one, sir; one, two, three; third, third one". The crew began the taxi and proceeded to identify the unmarked taxiways using an airport diagram as they reached them. The crew successfully identified the first two taxiways (C-1 and C-2), but their discussion in the cockpit never indicated that they had sighted the third taxiway (C-3), which they had been instructed to use.[16] There were no markings or signs to identify the runway exits and they were in conditions of poor visibility. The Pan Am crew appeared to remain unsure of their position on the runway until the collision, which occurred near the intersection with the fourth taxiway (C-4).

The angle of the third taxiway would have required the plane to perform a turn of approximately 148°, which would lead back toward the still-crowded main apron. At the end of C-3, the Pan Am would have to make another 148° turn in order to continue taxiing towards the start of the runway. Taxiway C-4 would have required two 35° turns. A study carried out by the Air Line Pilots Association after the accident concluded that making the second 148° turn at the end of taxiway C-3 would have been "a practical impossibility". Subsequent performance calculations and taxi tests with a Boeing 747 turning off on an intersection comparable to the C-3 at Tenerife, as part of the Dutch investigation, indicate that in all probability the turns could have been made. The official report from the Spanish authorities explains that the controller instructed the Pan Am aircraft to use the third taxiway because this was the earliest exit that they could take to reach the unobstructed section of the parallel taxiway.

3. Communication Misunderstand KLM Crew (captain, engineer, co-pilot), Tenerife Tower, Pan Am

Immediately after lining up, the KLM pilot advanced the throttles and the aircraft started to move forward. The co-pilot advised the captain that ATC clearance had not yet been given, and Captain Veldhuyzen van Zanten responded, "I know that. Go ahead, ask." Meurs then radioed the tower that they were "ready for take-off" and "waiting for our ATC clearance". The KLM crew then received instructions which specified the route that the aircraft was to follow after take-off. The instructions used the word "take-off," but did not include an explicit statement that they were cleared for take-off.

Meurs read the flight clearance back to the controller, completing the readback with the statement: "We are now at take-off." Captain Veldhuyzen van Zanten interrupted the co-pilot's read-back with the comment, "We're going." The controller, who could not see the runway due to the fog, initially responded with "OK" (terminology which is nonstandard), which reinforced the KLM captain's misinterpretation that they had take-off clearance. The controller's response of "OK" to the co-pilot's nonstandard statement that they were "now at take-off" was likely due to his misinterpretation that they were in take-off position and ready to begin the roll when take-off clearance was received, but not in the process of taking off. The controller then immediately added "stand by for take-off, I will call you," indicating that he had not intended the clearance to be interpreted as a take-off clearance. A simultaneous radio call from the Pan Am crew caused mutual interference on the radio frequency, which was audible in the KLM cockpit as a three-second-long whistling sound (or heterodyne). This caused the KLM crew to miss the crucial latter portion of the tower's response. The Pan Am crew's transmission was "We're still taxiing down the runway, the Clipper 1736!" . This message was also blocked by the interference and inaudible to the KLM crew. Either message, if heard in the KLM cockpit, would have alerted the crew to the situation and given them time to abort the take-off attempt. Due to the fog, neither crew was able to see the other plane on the runway ahead of them. In addition, neither of the aircraft could be seen from the control tower, and the airport was not equipped with ground radar. After the KLM plane had started its take-off roll, the tower instructed the Pan Am crew to "report when runway clear." The Pan Am crew replied: "OK, we'll report when we're clear." On hearing this, the KLM flight engineer expressed his concern about the Pan Am not being clear of the runway by asking the pilots in his own cockpit, "Is he not clear, that Pan American?" Veldhuyzen van Zanten emphatically replied "Oh, yes" and continued with the take-off.

ACCIDENT MODEL USED TO EXPLAIN THE ACCIDENT For this accident, the Swiss Cheese model would be the appropriate model that can be used to justify the causal factors. Accident happened through a chain of events. The chain of events are represented in the model as holed-layers. Although there are many layers, but it also possesses weaknesses that is the holes. With the consistency of holes existed in each and every layers, it justified why the accident happened. This model are also widely used in risk analysis and management especially in aviation industry

Should any obstacle blocks the hole, it will prevent an accident. Four broad categories of Swiss Cheese Model is:   

Organizational influences Surveillance unsafe Prerequisite for unsafe Act



Unsafe Acts

After this catastrophic event, there are numbers of lessons that has to be taken. The standard communication and interpersonal interactions throughout the flight also has to be changed in order for the tragedy not to be repeated. As we progress, the Swiss Cheese Model is a useful tool to explain this accident. With numbers of peculiar events and the piling up of latent failures, it takes little number of active failures in the form of unsafe acts to trigger the disaster. Holes in the cheese Throughout this analysis, we can see clearly on how all the holes in the cheese were linked up and finally, creating the disaster. 1. Explosion at Gran Canaria Airport Originally, both the Pan Am Flight 1736 and KLM Flight 4805 were scheduled to arrive at Gran Canaria airport that day. But because there were two bomb explosions reported at that airport, security had been compromised. Therefore any commercial airliner was not being able to seek permission to land. Eventually, both of the flight were forced to divert to Los Rodeos airport. 2. Size & Characteristics of Los Rodeos Airport (Tenerife) The Los Rodeos International Airport is relatively small in size compared to the Gran Canaria Airport. It only has one runway and one main taxiway that only serves a small number of regional flight. Due to the nature of the airport, the air traffic controllers (ATC) had no choice but to instruct both of the jumbos to taxi, back-track down the runway to line up for take-off. The first aircraft, KLM 5805 was instructed to taxi down the entire runway while the Pan Am 1736 was instructed to do the same thing as the KLM, but instead pull off into the third taxiway (C-3). 3. Dense Fog in Tenerife Located at 633 metres above the sea level, Los Rodeos Airport is one of the high elevation airport in the world. At the time of the event, Los Rodeos Airport

was covered with low scattered cloud which result in dense fog. As the jumbos began taxi down the runway, the foggy condition worsen from the visibility of 500m to just 100m. This leads to the Pan Am 1736 failed from seeing which taxiway they were instructed to turn at. It is worth noting that the KLM sitting idle at the other end of the runway cannot even see the Pan Am 1736. To make it worst, after the collision, the dense fog confused initial emergency responders thus making them unaware of there was a second aircraft in the accident. 4. Absence of Ground Radar The surface movement radar (SMR) has been introduced by the International Civil Aviation Organization (ICAO) since 1950’s. By utilizing the SMR, air traffic controllers can have a bird’s eye view on what is moving on the airport ground. Unfortunately, being a small regional airport, Los Rodeos Airport did not installed this technology at the time of the event. Because of that, the dense fog completely blinded the ATC’s view from locating the jumbos and only relied on the description that crew of an aircraft provided through radio transmissions along the way. 5. KLM 4805 Fully Refuels at Los Rodeos Airport Refuelling is a normal procedure in aviation industry. But in this event, the additional time taken to refuel the KLM aircraft delayed take-off by an additional 35 minutes, subsequently allowed the fogs to worsen thus reducing the visibility. The extra weight from the fuel leads to the Boeing 747 to require longer runway to reach take-off speed. Without the additional weight, KLM 4805 may have cleared Pan Am 1736 prior to collision. Last but not least, the extra fuel directly led to a disastrous scale of inferno when it ignited at the moment of the collision, which resulted on low survival rate for engers. 6. Pan Am 1736 Misses Turn In the ATC’s instruction the Pan Am 1736 was supposed to exit the runway via taxiway C3. The collision took place near the fourth taxiway exit that is

taxiway C4. A following analysis done by investigators shows that the exit sign of taxiway C3 was poorly marked.

7. Personality Traits of Key Personnel: After the cockpit voice recorder conversations were released, Captain Veldhuyzen van Zanten of KLM 4805 was highly criticized for his character along this event. At first look, it seems that Capt Veldhuyzen van Zanten’s eagerness to depart led him to increase the throttle up with the intention to takeoff without the consent of ATC. When it happened for the first time, the KLM First Officer remind the eager captain of no ATC clearance had been issued for take-off. In the second time though, the KLM Flight Engineer voiced out his nervous feeling about this action. The captain however disregard his colleague and began the take-off sequence. Back then, Veldhuyzen van Zanten was KLM’s super star that holds the position of chief of flight training. He is also featured on so many KLM ment on their in-flight magazines showing that the company adores him. Because of this position, the co-pilot and flight engineer was considered to feel inferior thus making turned them into the state of inability clarify the clearance from the ATC to take-off.

ANALYSIS BY THE INVESTIGATORS

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About 70 crash investigators from Spain, the Netherlands, the United States, and the two airline companies were involved in the investigation.

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Investigation showed that there had been misinterpretations and false assumptions.

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The investigation concluded that the fundamental cause of the accident was that Captain Veldhuyzen van Zanten took off without take-off clearance.

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The investigators suggested that the reason for his mistake might have been a desire to leave as soon as possible in order to comply with KLM's duty-time regulations, and before the weather deteriorated further.

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Other major factors contributing to the accident were: 1. The sudden fog greatly limited visibility. The control tower and the crews of both planes were unable to see one another. 2. Interference from simultaneous radio transmissions, with the result that it was difficult to hear the message.

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The following factors were considered contributing but not critical: 1. Use of ambiguous non-standard phrases by the KLM co-pilot ("We're at take-off") and the Tenerife control tower ("OK"). 2. The Pan Am aircraft had not exited the runway at C-3. 3. The airport was (due to rerouting from the bomb threat) forced to accommodate a great number of large aircraft, resulting in disruption of the normal use of taxiways.

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The Dutch authorities were reluctant to accept the Spanish report blaming the KLM captain for the accident.

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The Netherlands Department of Civil Aviation published a response that, whilst accepting that the KLM aircraft had taken off "prematurely".

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They argued that he alone should not be blamed for the "mutual misunderstanding" that occurred between the controller and the KLM crew, and that limitations of using radio as a means of communication should have been given greater consideration.

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In particular, the Dutch response pointed out that: 1. The crowded airport had placed additional pressure on all parties, KLM, Pan Am, and the controller.

2. The transmission from the tower in which the controller ed KLM their ATC clearance was ambiguous and could have been interpreted as also giving take-off clearance. 3. The Pan Am had taxied beyond the third exit. Had the plane turned at the third exit as instructed, the collision would not have occurred. 

This was one of the first accident investigations during which the contribution of "human factors" was studied. The human factors included: 1. The flight was one of Captain Veldhuyzen van Zanten's first after spending six months training new pilots on a flight simulator where he had been in charge of everything (including simulated ATC), hence having been away from the real world of flying for an extended period. 2. The flight engineers and the first officer's apparent hesitation to challenge Veldhuyzen van Zanten further. The official investigation suggested that this might have been because the captain was not only senior in rank, but also one of the most respected pilots working for the airline. 3. The reason only the flight engineer on the KLM plane reacted to the radio transmission "OK, we'll report when we're clear" might lie in the fact that by then he had completed his pre-flight checks, whereas his colleagues were experiencing an increased workload, just at the same time as the visibility worsened. 4. Investigation concluded that the KLM crew did not realise that the transmission "Papa Alpha one seven three six, report when runway clear" was directed at the Pan Am because this was the first and only time the Pan Am was referred to by that name. Before that, the Pan Am was called "Clipper one seven three six".

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The extra fuel the KLM plane took on added several factors: 1. It delayed take-off an extra 35 minutes, which gave time for the fog to settle in 2. it added over forty tons of weight to the plane, which increased the takeoff distance and made it more difficult to clear the Pan Am when taking off 3. It increased the size of the fire from the crash that ultimately killed everyone on board.

RECOMMENDATIONS Recommendation is a suggestion or proposal as to the best course of action. There are numerous recommendation that can be applied especially for this type of accident. Those recommendations are:1. All aviation communication should be conducted precise standardized terminology. 2. To ensure that all personnel involved in aviation are fluent in English and speak in minimal accident a rigid standard should be applied to this matter. 3. To minimize the potential of “training syndrome” pilot instructor should fly the majority of their flight time in regular line operations. 4. During ATC clearance the word “Take off” should never be used. 5. Every carrier airports should installed a ground radar. 6. Commercial aircraft should not taxi at any airport in visibility condition below 150 metres unless suitable taxi lighting or other visual aids and airport ground radar are operational. 7. Means should be taken to avoid confusion of an ATC clearance with take-off clearance. This may involve changing the name “ATC clearance” so that it is clearly understood to be nothing more than a description of the route to be flown.

8. Whenever an aircraft is moving it is practicable to put the landing gears on. 9. For every carrier aircraft, a strobe anti-collision light should be installed and operated whenever practicable. 10. To confirm take off clearance in all airport a redundant means should be provided. 11. The roles of each cockpit member should be researched by an appropriate institution to determine optimum crew member interaction in order to minimize the probability of human error.

INFORMATION RETRIEVED FROM CVR AND FDR RELATED TO CAUSED OF THE ACCIDENT

There are several incident that have been identified based on the Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR) founding 1. According to the CVR it shows that the KLM Pilot was convinced that he had been cleared for take-off, however the Tenerife control tower was considering that the KLM 747 was stationary at the end of the runway and awaiting for the take-off clearance. It also appeared that the KLM’s co-pilot was not as certain about take-off clearance as the captain. 2. During that time also, the recorded CVR suggested that during the fatal accident the Spanish control tower crew had been listening to a football match on the radio and obviously they have been distracted. 3. Stand by for take-off, I will call you"...but unfortunately that transmission was not heard clearly as two of the aircraft attempted to transmit at the same time. 4. The tower controller, in no way alarmed, has in his routine, not requested a confirmation of his order to KLM: "Stand by for take-off". 5. The crew also faced some difficulties in term of hearing for instruction as the background conversation in the control tower too loud. 6. The last two messages were radioed simultaneously and were therefore heard as a long four-second high-pitched sound

CONCLUSION

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Trough out the event that lead to the tragic accident, it is evident that language barriers including accent and idiomatic usage, degraded and disturb information transfer.

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The KLM captain was under great stress due to concern about the legal aspects of the Dutch duty time limits and worsening weather condition.

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The Pan Am captain already expressed a desire to hold clear of the runway, unfortunately the controller did not receive this information.

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The accident also occur due to both crews had difficulty understanding taxi instructions, particularly those of the ground controller.

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The training syndrome may have influenced the KLM’S captain decision to make an early conclusion that he was cleared to take-off.

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The Pan Am crew ed the third left taxiway in poor visibility while concentrating on the ATC clearance being given to KLM. Due to their airplane geometry, they do not believe this to be their assigned exit.

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The controller did not obtain or received an acknowledgement from KLM behalf to his order to “stand by for take-off”

REFERENCES

1. 2. 3. 4. 5. 6. 7. 8. 9.

http://en.wikipedia.org/wiki/Aviation_safety#Air_Safety_Investigators http://www.nj.gov/transportation/airwater/aviation/safety.shtm http://www.1001crash.com/index-page-tenerife-lg-2-numpage-6.html http://en.wikipedia.org/wiki/Tenerife_airport_disaster journal : Human Factor Report on Tenerife Accident, Alpa Study, 1977 http://en.wikipedia.org/wiki/Tenerife_airport_disaster project-tenerife.com/engels/PDF/alpa.pdf http://en.wikipedia.org/wiki/Tenerife_airport_disaster http://www.tiptoptens.com/2013/11/25/top-10-worst-aviation-accidents/