Peer Pressure “The Tenerife Disaster 1977”

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 Islands. 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.

When Gran Canaria reopened, the parked aircraft blocking the taxiway at Tenerife required both of the 747s to taxi on the only runway in order to get in position for takeoff. The fog was so thick that neither aircraft could be seen from the other, and the controller in the tower could not see the runway or the two 747s on it. As the airport did not have ground radar, the controller could find where each airplane was only by voice reports over the radio.

As the accident occurred in Spanish territory, Spain was responsible for investigating the accident. The crash involved aircraft from the United States and the Netherlands, which both conducted investigations as well.

The investigations 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 admitted their crew was responsible for the accident, and the airline financially compensated the victims’ relatives.

The accident had a lasting influence on the industry, particularly in the area of communication. An increased emphasis was placed on using standardized phraseology in ATC communication by controllers and pilots alike, thereby reducing the chance for misunderstandings. As part of these changes, the word “takeoff” was removed from general usage, and is only spoken by ATC when clearing an aircraft to take off or when cancelling that same clearance. Less experienced flight crew members were encouraged to challenge their captains when they believed something was not correct, and captains were instructed to listen to their crew and evaluate all decisions in light of crew concerns. This concept was later expanded into what is known today as Crew Resource Management (CRM), in which training is now mandatory for all airline pilots.

Flight history: For both planes, Tenerife was an unscheduled stop. Their destination was Gran Canaria International Airport (also known as Las Palmas Airport or Gando Airport), serving Las Palmas on the nearby island of Gran Canaria. Both are in the Canary Islands, an autonomous community of Spain located in the Atlantic Ocean off the southwest coast of Morocco.

Pan Am Flight 1736 had originated at Los Angeles International Airport, with an intermediate stop at New York’s John F. Kennedy International Airport (JFK). The aircraft was a Boeing 747-121, registration N736PA, named Clipper Victor. Of the 380 passengers (mostly of retirement age, but including two children), 14 had boarded in New York, where the crew was also changed. The new crew consisted of Captain Victor Grubbs, First Officer Robert Bragg, and Flight Engineer George Warns. There were 13 other crew members. This aircraft had operated the inaugural 747 commercial flight on January 22, 1970.  In its first year of service, it also became the first 747 to be hijacked.  It left JFK for San Juan, Puerto Rico, at 1:07 am on August 2, 1970, with 359 or 360 passengers and 19 crew. One hour and forty minutes later, a young man named R. Campos produced a gun and a bottle out of a bag that he claimed contained explosives, and hijacked the airplane to Havana, where it touched down at Jose Marti Airport at 5:31 am. The first 747 to land in Cuba, it was met by Cuba’s Premier Fidel Castro.

KLM Flight 4805, a charter flight for Holland International Travel Group, had arrived from Amsterdam Airport Schiphol, the Netherlands.  Its captain was Jacob Veldhuyzen van Zanten, KLM’s chief flying instructor. The First Officer was Klaas Meurs and the Flight Engineer was Willem Schreuder. The aircraft was a Boeing 747-206B, registration PH-BUF, named Rijn (Rhine). The KLM jet had 14 crew members and 235 passengers, including 52 children. Most of the KLM passengers were Dutch; four Germans, two Austrians and two Americans were also on the plane. After the aircraft landed at Tenerife, the passengers were transported to the airport terminal. One of the inbound passengers, who lived on the island, chose not to re-board the 747, leaving 234 passengers on board.


Diversion of aircraft to Los Rodeos: Both flights had been routine until they approached the islands. At 1:15 p.m., a bomb (planted by the separatist Fuerzas Armadas Guanches) exploded in the terminal of Gran Canaria International Airport, injuring one person. There had been a phone call warning of the bomb, and soon after another call claimed that a second bomb was at the airport. The civil aviation authorities had therefore closed the airport temporarily after the bomb detonated and diverted all of its incoming flights to Los Rodeos, including the two Boeing 747 aircraft involved in the disaster. The Pan Am crew indicated that they would prefer to circle in a holding pattern until landing clearance was given, but were ordered to divert to Los Rodeos.

In all, five large aircraft were diverted to Los Rodeos, a regional airport that could not easily accommodate them. The airport had only one runway and one major taxiway parallel to it, with four taxiways connecting the two. While waiting for Gran Canaria airport to reopen, the diverted aircraft took up so much space that they were parked on the long taxiway, meaning that it could not be used for taxiing. Instead, departing aircraft had to taxi along the runway to position themselves for takeoff, a procedure known as a runway back taxi or backtrack.


Los Rodeos Airport. Simplified map of runway, taxiways, and aircraft. The red star indicates the location of impact. Not to scale

After the threat at Gran Canaria had been contained, authorities reopened that airport. The Pan Am aircraft was ready to depart from Tenerife, but the KLM plane and a refueling vehicle obstructed its access to the runway. The Pan Am aircraft was unable to maneuver around the fueling KLM, reach the runway and depart due to a lack of safe clearance, which was a mere 12 ft (3.7 m). Captain Veldhuyzen van Zanten had decided to fully refuel at Los Rodeos instead of Las Palmas, apparently to save time. The refueling took about 35 minutes. After that, the passengers were brought back to the plane. The search for a missing Dutch family of four delayed the flight even further. A tour guide chose not to reboard for Las Palmas, because she lived on Tenerife and did not think it practical to fly to Gran Canaria just to return to Tenerife the next day. She would be the only person who flew from Amsterdam to Tenerife on Flight 4805 to survive, as she was not on the plane at the time of the accident.

Taxiing and takeoff preparations: 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 takeoff 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 takeoff position on Runway 30.


Los Rodeos plan view: Tenerife runway showing relative positions of aircraft at different times (T1, T2, T3) and point of impact (T4).

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 (ALPA) 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.

Weather conditions at Los Rodeos: Los Rodeos airport is at 633 metres (2,077 feet) above sea level, which gives rise to cloud behavior that differs from that at many other airports. Clouds at 600 m (2,000 ft) above ground level at the nearby coast are at ground level at Los Rodeos. 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 plane 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).

Communication misunderstandings: 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 takeoff” and “waiting for our ATC clearance”.

The KLM crew then received instructions which specified the route that the aircraft was to follow after takeoff. The instructions used the word “takeoff,” but did not include an explicit statement that they were cleared for takeoff. Meurs read the flight clearance back to the controller, completing the read back with the statement: “We are now at takeoff.” Captain Veldhuyzen van Zanten interrupted the co-pilot’s read-back with the comment, “We’re going.”

*For the benefit of non-aviation minded readers, an ATC clearance is a route clearance only given by the tower on behalf of the air traffic control centre, i.e. you will proceed on this airway, climb to this flight level (altitude) etc. It is separate from a take-off clearance which is normally requested by the pilot once the aircraft is lined up on the runway and, ready to go–Mohammad S. Husain

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 takeoff clearance. The controller’s response of “OK” to the co-pilot’s nonstandard statement that they were “now at takeoff” was likely due to his misinterpretation that they were in takeoff position and ready to begin the roll when takeoff 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 takeoff 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 takeoff 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 takeoff 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 takeoff.

Collision: According to the Cockpit Voice Recorder (CVR), the Pan Am pilot said, “There he is!” when he spotted the KLM’s landing lights through the fog just as his plane approached exit C-4. When it became clear that the KLM was approaching at takeoff speed, Grubbs exclaimed, “Goddamn, that son-of-a-bitch is coming straight at us!” while the co-pilot Robert Bragg yelled, “Get off! Get off! Get off!”The Pan Am crew applied full power to the throttles and took a sharp left turn towards the grass in an attempt to avoid a collision.  By the time the KLM pilots saw the Pan Am, they were already traveling too fast to stop. In desperation the pilots prematurely rotated the aircraft and attempted to clear the Pan Am by climbing away, causing a severe tail strike for 22 m (72 ft).

The KLM was within 100 m (330 ft) of the Pan Am when it left the ground. Its nose gear cleared the Pan Am, but the engines, lower fuselage and main landing gear struck the upper right side of the Pan Am’s fuselage at approximately 140 knots (260 km/h; 160 mph), ripping apart the center of the Pan Am jet almost directly above the wing. The right side engines crashed through the Pan Am’s upper deck immediately behind the cockpit.

The KLM plane remained briefly airborne following the collision, but the impact with the Pan Am had sheared off the outer left engine, caused significant amounts of shredded materials to be ingested by the inner left engine, and damaged the wings. The KLM aircraft immediately went into a stall, rolled sharply, and hit the ground at a point approximately 150 m (500 ft) past the collision, sliding a further 300 m (1,000 ft) down the runway. The full load of fuel, which had caused the earlier delay, ignited immediately in a large fireball that could not be subdued for several hours.

One of the 61 survivors of the Pan Am flight, John Coombs of Haleiwa, Hawaii, said that sitting in the nose of the plane probably saved his life: “We all settled back, and the next thing an explosion took place and the whole port side, left side of the plane, was just torn wide open.”

Both airplanes were destroyed. All 234 passengers and 14 crew members in the KLM plane died, as did 326 passengers and nine crew members aboard the Pan Am, primarily due to the fire and explosions resulting from the fuel spilled and ignited in the impact. The other 54 passengers and seven crew members aboard the Pan Am aircraft survived, including the captain, first officer and flight engineer. Most of the survivors on the Pan Am walked out onto the intact left wing, the side away from the collision, through holes in the fuselage structure. The Pan Am’s engines were still running for a few minutes after the accident despite First Officer Bragg’s intention to turn them off. The top part of the cockpit, where the engine switches were located, had been destroyed in the collision, and all control lines were severed, leaving no method for the flight crew to control the aircraft’s systems. Survivors waited for rescue, but it did not come promptly, as the firefighters were initially unaware that there were two aircraft involved and were concentrating on the KLM wreck some distance away in the thick fog and smoke. Eventually, most of the survivors on the wings dropped to the ground below.


Veldhuyzen van Zanten in a KLM magazine

Captain Veldhuyzen van Zanten was KLM’s chief of flight training and one of their most senior pilots. His photograph was used for publicity materials such as magazine advertisements, including the inflight magazine on board PH-BUF. As such, KLM suggested that he should be part of the investigation team, before learning that he was the captain involved. He had given the co-pilot on the flight his Boeing 747 qualification check about two months before the accident.

Cockpit and ATC tower communications

These communications are taken from the cockpit voice recorders of both aircraft, as well as from the Tenerife control tower’s tapes.

Time span covered: 1705:36–1706:50 ( 1 minute 14 secs)

 1705:36.7-[KLM first officer completes pre-flight checklist. KLM 4805 is now at the end of the runway, in position for departure.]

 1705:41.5-KLM FIRST OFFICER: Wait a minute, we don’t have an ATC clearance. [This statement is apparently a response to an advancing of the throttles in the KLM.]

KLM CAPTAIN: No, I know that, go ahead, ask.

 1705:44.6 – 1705:50.8

KLM (RADIO): the KLM four eight zero five is now ready for take-off and we are waiting for our ATC clearance.

 1705:53.4 – 1706:08.1 –TENERIFE TOWER: KLM eight seven zero five [sic]* you are cleared to the Papa Beacon, climb to and maintain flight level nine zero, right turn after take-off, proceed with heading four zero until intercepting the three two five radial from Las Palmas VOR.

*Tenerife tower has used an erroneous call sign for KLM—Mohammad S. Husain

 1706:07.4-KLM CAPTAIN : Yes.

 1706:09.6 – 1706:17.8 –KLM (RADIO) : Ah roger, sir, we are cleared to the Papa Beacon flight level nine zero until intercepting the three two five. We are now at take-off* [or “uh…taking off”].

*I think the first officer was indicating that they have lined up on the runway and awaiting take-off clearance. There is language terminology issue–Mohammad S. Husain

 1706:11.1 –[KLM brakes released.]

 1706:12.3 –KLM CAPTAIN: We gaan … check thrust. [We’re going … check thrust].

 1706:14.0- [Engine acceleration audible in KLM cockpit]

 1706:18.2 – 1706:21.2

TENERIFE TOWER : OK*…. Stand by for take-off, I will call you. [Only the start of this message could be heard clearly by the KLM crew due to a radio heterodyne]

*That means they heard OK only and misinterpreted as affirmative for take-off–Mohammad S. Husain

 1706:19.3 –PAN AM CAPTAIN No… uh.

 1706:20.3 –PAN AM (RADIO) : And we’re still taxiing down the runway, the clipper one seven three six. [This message was not heard completely clear by the KLM crew due to a radio heterodyne.]

1706:25.5-TENERIFE TOWER: Ah, papa alpha one seven three six* report the runway clear.

*The controller uses the call sign papa alpha one seven three six for Pan Am for the first time. Normally it was Clipper 1736-Mohammad S. Husain

1706:29.6-PAN AM (RADIO): OK, will report when we’re clear.

1706:31.7-TENERIFE TOWER: Thank you. [This last radio communication involving the two aircraft. Everything which follows is intra-cockpit communication amongst its respective crews.]


1706:32.1-PAN AM CAPTAIN: Let’s get the fuck out of here.

1706:34.9-PAN AM FIRST OFFICER: Yeah, he’s anxious, isn’t he?

1706:36.2-PAN AM FLIGHT ENGINEER: Yeah, after he held us up for half an hour, that [expletive]. Now he’s in a rush.

1706:32.4-KLM FLT ENGR: Is hij er niet af dan? [Is he not clear then?]

1706:34.1-KLM CAPTAIN: Wat zeg je? [What do you say?]

1706:34.2 –KLM UNKNOWN: Yup.

1706:34.7KLM FLIGHT ENGINEER: Is hij er niet af, die Pan American? [Is he not clear, that Pan American?]

1706:35.7 –KLM CAPTAIN: Jawel. [Oh yes. – emphatic]


1706:40.5-[Pan Am captain sees landing lights of KLM Boeing at approx. 700 m]

1706:40.6 –PAN AM CAPTAIN: There he is … look at him. Goddamn that son-of-a-bitch is coming!

1706:45.9-PAN AM FIRST OFFICER: Get off! Get off! Get off!

1706:43.5 –KLM FIRST OFFICER:   V-1.

1706:44.0 –[PH-BUF (KLM 4805) starts rotation.]

1706:47.4-KLM CAPTAIN: Oh shit!

1706:50-N736PA (Pan Am 1736) records sound of collision.

Airport closure: Los Rodeos airport, the only operating airport on Tenerife in 1977, was closed to all fixed wing traffic for two days. The first crash investigators to arrive at Tenerife the day after the crash travelled there by way of a three hour boat ride from Las Palmas. The first aircraft that was able to land was a United States Air Force C130 transport, which landed on the airport’s main taxiway at 12:50 p.m. on March 29. It transported all surviving and injured passengers from Tenerife to Las Palmas; many of the injured would be taken from there to Air Force bases in the United States for further treatment.

Spanish army troops were tasked with clearing crash wreckage from the runways and taxiways. By March 30, a small plane shuttle service was approved, but large jets still could not land. Los Rodeos was fully reopened on April 3, after wreckage had been fully removed and engineers had repaired the airport’s runway.


About 70 crash investigators from Spain, the Netherlands, the United States, and the two airline companies were involved in the investigation. Facts showed that there had been misinterpretations and false assumptions. Analysis of the CVR transcript showed that the KLM pilot was convinced that he had been cleared for takeoff, while the Tenerife control tower was certain that the KLM 747 was stationary at the end of the runway and awaiting takeoff clearance.

It appears KLM’s co-pilot was not as certain about take-off clearance as the captain.

Probable cause

The investigation concluded that the fundamental cause of the accident was that Captain Veldhuyzen van Zanten took off without proper clearance. The investigators suggested 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.

Other major factors contributing to the accident were:

  • The sudden fog greatly limited visibility. The control tower and the crews of both planes were unable to see one another.
  • Interference from simultaneous radio transmissions, with the result that it was difficult to hear the message.

The following factors were considered contributing but not critical:

  • Use of ambiguous non-standard phrases by the KLM co-pilot (“We’re at take off”) and the Tenerife control tower (“OK”).
  • The Pan Am aircraft had not exited the runway at C-3.
  • The airport was forced to accommodate a great number of large aircraft due to rerouting from the bomb threat, resulting in disruption of the normal use of taxiways.

Dutch response

  • The Dutch authorities were reluctant to accept the Spanish report blaming the KLM captain for the accident. The Netherlands Department of Civil Aviation published a response that, while accepting that the KLM aircraft had taken off “prematurely”, 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. In particular, the Dutch response pointed out that:
  • The crowded airport had placed additional pressure on all parties, KLM, Pan Am, and the controller;
  • Sounds on the CVR suggested that during the accident the Spanish control tower crew had been listening to a football match on the radio and may have been distracted.
  • The transmission from the tower in which the controller passed KLM their ATC clearance was ambiguous and could have been interpreted as also giving take-off clearance. In support of this part of their response, the Dutch investigators pointed out that Pan Am’s messages “No! Eh?” and “We are still taxiing down the runway, the Clipper 1736!” indicated that Captain Grubbs and First Officer Bragg had recognized the ambiguity (this message was not audible to the control tower or KLM crew due to simultaneous cross-communication);
  • 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.
  • Although the Dutch authorities were initially reluctant to blame Captain Veldhuyzen van Zanten and his crew, the airline ultimately accepted responsibility for the accident. KLM paid the victims or their family’s compensation ranging between $58,000 and $600,000. The sum of settlements for property and damages was $110 million (an average of $189,000 per victim, due to limitations imposed by European Compensation Conventions in effect at the time).


  • This was one of the first accident investigations during which the contribution of “human factors” was studied. The human factors included:
  • 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.
  • The flight engineer’s 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. This view is questioned by Jan Bartelski, a former KLM Captain and the president of the International Federation of Air Line Pilots’ Associations (IFALPA), who knew both men and believes that this explanation is inconsistent with his experience of their personalities. 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 as the visibility worsened.
  • The ALPA study group 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”, with the proper call sign.

The extra fuel the KLM plane took on added several factors:

  • it delayed takeoff an extra 35 minutes, which gave time for the fog to settle in;
  • 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;
  • it increased the size of the fire from the crash that ultimately killed everyone on board.

 Safety response

  • As a consequence of the accident, sweeping changes were made to international airline regulations and to aircraft. Aviation authorities around the world introduced requirements for standard phrases and a greater emphasis on English as a common working language.
  • Several national air safety boards began penalizing pilots for disobeying air traffic controllers’ orders. Air traffic instruction should not be acknowledged solely with a colloquial phrase such as “OK” or even “Roger” (which simply means the last transmission was received]), but with a read back of the key parts of the instruction, to show mutual understanding. The phrase “take off” is now spoken only when the actual takeoff clearance is given or when cancelling that same clearance (i.e. “cleared for take-off” or “cancel take-off clearance”). Up until that point, aircrew and controllers should use the phrase “departure” in its place, e.g. “ready for departure”. Additionally, an ATC clearance given to an aircraft already lined-up on the runway must be prefixed with the instruction “hold position”.
  • Cockpit procedures were also changed. Hierarchical relations among crew members were played down. More emphasis was placed on team decision-making by mutual agreement, part of what has become known in the industry as Crew Resource Management.
  • In 1978 a second airport was inaugurated on the island: the new Tenerife-South Airport (TFS). This airport now serves the majority of international tourist flights. Los Rodeos, renamed to Tenerife North Airport (TFN), was then used only for domestic and inter-island flights. In 2002 a new terminal was opened and it carries international traffic once again, including budget airlines.
  • The Spanish government installed ground radar at Tenerife North following the accident.


  • ALPA report on the crash PDF (2.70 MB), p. 2 (PDF page 6 of 97) “The study group notes with approval that the official report of the Spanish government has, itself, included a section on human factors involved in this accident. We feel that this is an excellent beginning toward a better understanding of the causal factors of aviation accidents, an idea whose time has finally come.”
  • PDF (5.98 MB), section 5.2, p. 38 (PDF page 41 of 63) “… these circumstances could have induced the co-pilot not to ask any questions, assuming that his captain was always right”
  • Bartelski, Jan (2001). Disasters in the air: mysterious air disasters explained. Airlife. ISBN 978-1-84037-204-5. As far as the allegations that co-pilots would not have the nerve to stand up to van Zanten during flight because of his senior position in the company, and that their career could be ruined by his adverse report, this was another example of completely false presumptions. Van Zanten was a serious and introverted individual but with an open-hearted and friendly disposition. He was a studious type and was regarded as the company’s pilot expert on the Boeing 747 systems. Nevertheless, he would have been the last person on the flight desk not to accept his co-pilot’s advice or warning. He believed in partnership, to the extent that he insisted on his first officers addressing him during flight as Jaap and not Captain van Zanten He had learnt much about cockpit management by representing KLM at an IATA Conference in Istanbul and was trying to put this into practice . . . Meurs was not the type to have been easily intimidated by a superior rank and would not have easily given in under stress. Although new to the 747 (he had only ninety hours on that type), he was formerly a temporary DC-8 captain. For personal reasons, he waived his seniority right for a DC-9 command and opted to fly the 747 as a first officer. Meurs was an extrovert and liked to enjoy life, a contrasting disposition to van Zanten. Both complemented each other in personalities as well as in their operational background. What van Zanten lacked in route experience, particularly in the Canary Islands area, Meurs compensated for by his ultimate knowledge of the local situation from his many past flights through Las Palmas. The reverse applied to the handling of the 747. As for his profiency as a co-pilot, I found Meurs cooperative, alert, and far from a meek and mild type. In fact, the opposite was more likely. He could be somewhat abrupt and direct in his manner, as was evident from the way he stopped van Zanten from opening the throttles
  • ALPA report on the crash PDF (2.70 MB), p. 22 (PDF page 26 of 97). “Both pilots were contending with heavy demands on their attention as the visibility rapidly worsened. The flight engineer, to the contrary, had completed the heaviest part of his workload and was now reverting to an instrument monitoring mode.It is our opinion that the flight engineer, like the pilots, did not perceive the message from the controller to the Pan Am asking them to report when runway clear”. (Because of the use of the address “Papa Alpha).”
  • Th Spanish report said 55,500 litres of jet fuel based on a density of 0.8705 kg/l that weighed some 45 metric tons, or 49 US tons.  Archived April 12, 2009.
  • The 55 tons of fuel the Dutch plane had taken on created a massive fireball that sealed the fate of everyone on board NOVA | the deadliest plane crash, transcript

Accident summary

  • Date: March 27, 1977
  • Summary: Pilot error, runway incursion, heavy fog, limitations and failures in communication
  • Site: Los Rodeos Airport (now Tenerife-North Airport) Tenerife, Canary Islands, Spain
  • Total injuries (non-fatal) 61
  • Total fatalities  583
  • Total survivors  61

First aircraft: The KLM Boeing 747-206B (PH-BUF) involved in the accident

  • Type: Boeing 747-206B
  • Registration: PH-BUF
  • Name: Rijn (“Rhine”)
  • Operator: KLM Royal Dutch Airlines
  • Registration: PH-BUF
  • Flight origin: Schiphol Airport Amsterdam, Netherlands
  • Destination: Gran Canaria Airport Canary Islands, Spain
  • Passengers: 234
  • Crew: 14
  • Fatalities: 248 (all)
  • Survivors: 0



Second aircraft: A Pan Am Boeing 747-121 similar to the one involved

  • Type: Boeing 747-121
  • Registration: N736PA
  • Name: Clipper Victor
  • Operator: Pan American World Airways
  • Flight origin: Los Angeles Int’l Airport Los Angeles, United States
  • Stopover: John F. Kennedy Int’l Airport New York City, United States
  • Destination: Gran Canaria Airport Canary Islands, Spain
  • Passengers: 380
  • Crew: 16
  • Injuries (non-fatal): 61
  • Fatalities: 335 (326 passengers, 9 crew)
  • Survivors: 61


A Dutch national memorial and final resting place for the victims of the KLM plane is located in Amsterdam, at Westgaarde cemetery. There is also a memorial at the Westminster Memorial Park and Mortuary in Westminster, California.


Monument in Westgaarde Cemetery, Amsterdam

The 30th anniversary marked the first time that Dutch and American next of kin, and aid helpers from Tenerife, joined an international commemoration service held at the Auditorio de Tenerife in Santa Cruz; the International Tenerife Memorial March 27, 1977, was inaugurated at the Mesa Mota on March 27, 2007. The monument was designed by Dutch sculptor Rudi van de Wint.


Tenerife Memorial

By courtesy

6 thoughts on “Peer Pressure “The Tenerife Disaster 1977”

  1. When this accident happened (March 27, 1977), I was in Denver, CO for my training as co-pilot on the B747. I had been sent by my airline, PIA to the United Airlines Training Centre for the purpose. Earlier, I had been promoted as co-pilot B707 in 1974 and encountered a degree of hostility from some captains on this equipment. They probably felt that our group of co-pilots would not be of much help to them because of our inexperience; the underlying reason could be: we did not deserve to go abroad so quickly as the B707 flew internationally.
    At this stage my experience was only as a copilot of Fokker F-27, and I had started flying that aircraft in 1969. However the Civil Aviation Authorities in Pakistan made it conditional that we did a six landings training session every six months on the B707 if they had not been completed while flying online. When I came on the B747 as copilot, I had commanded the Fokker F-27.
    In this accident I feel that Captain of the KLM flight, management executive, felt obliged for a timely scheduled arrival back at Amsterdam. In a bid to save time at Tenerife, he had the aircraft refuelled at the last minute before departure, unnecessarily delaying Pan Am by at least thirty minutes. He was in a hurry to complete the flight within the flight time allotted and as a result was more focused on getting airborne from Tenerife than being more exacting on procedures.
    By acknowledging that the take off clearance and the airways clearance had not been received at the take-off point to his crew when he was challenged by the first officer, we can gauge how much of haste was there in his actions; he had opened power for take-off knowing no formal permission had been received and expecting the first officer to do the needful as the aircraft would gather speed on the take-off roll; he was not reasoning correctly under pressure.
    The Tower did not use standard phraseology and once used an erroneous call sign for KLM; KLM 8705 instead of KLM 4805 when giving the ATC clearance. Also the use of the term by the tower, ‘papa alpha 1736’, instead of Clipper 1736 when requesting him to report runway clear may not have registered with KLM at take-off point. Two crucial transmissions we are informed were partially blocked due to simultaneous broadcasts by all three users.
    The KLM first officer had misgivings about the takeoff clearance on line up, yet was not forceful enough to assert that it had not been received. He was interrupted when reading back the ATC clearance; there was no take off clearance given.
    The KLM flight engineer expressed misgivings about the position of Pan Am on the runway, but did not assert when the captain had opened power on lining up with no formal permission of any kind from the tower. Haste makes waste.

    Both the flight crews, KLM and Pan Am were at the end of their duty cycle. Pan Am crew could look forward to a break after the short hop to Las Palmas. On the other hand, the KLM crew had one more sector to do after landing at Las Palmas with further delay looming there.

    In hindsight: The airport should have been closed when the visibility restricted any sighting of either aircraft on the runway and taxiways by the tower and it, itself was not visible to either aircraft for light signals of any kind.

  2. An ATC clearance is an airways clearance for the route to be flown. It has to be read back by the pilot after listening so that there is no misunderstanding about what has been heard. A takeoff clearance issued by the tower authorizes an aircraft to takeoff from the runway when received. It too has to be acknowledged by the pilot.

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