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'{{short description|1977 runway collision in Spain and deadliest accident in aviation history}} {{use American English|date=November 2015}} {{use mdy dates|date=July 2023}} {{Infobox aircraft occurrence | occurrence_type = Accident | name = Tenerife airport disaster<br />{{nobold|{{small|KLM Flight 4805{{·}}Pan Am Flight 1736}}}} | image = Het verongelukte KLM-toestel De Rijn, Bestanddeelnr 929-1005 - cropped.jpg | image_upright = 1.2 | alt = | caption = Wreckage of the KLM aircraft on the runway at Los Rodeos | date = March 27, 1977 | summary = [[Runway incursion|Runway collision]]<!-- No causes in the summary, only circumstances; leave the causes for the article body per project consensus --> | site = {{longitem|style=line-height:1.2em;|[[Los Rodeos Airport]], [[Tenerife]], [[Canary Islands]], [[Spain]]}} | coordinates = {{Coord|28|28|53.94|N|16|20|18.24|W}} | total_survivors = 61 | total_fatalities = 583 | total_injuries = 61 | plane1_type = [[Boeing 747#747-200|Boeing 747-206B]] | plane1_name = ''Rijn'' ("[[Rhine]]") | plane1_image = KLM Boeing 747-200 PH-BUF (7491686916).jpg | plane1_image_upright = 1.2 | plane1_caption = PH-BUF, the KLM Boeing 747-206B<br />involved in the accident | plane1_operator = [[KLM|KLM Royal Dutch Airlines]] | plane1_tailnum = PH-BUF | plane1_IATA = KL4805 | plane1_ICAO = KLM4805 | plane1_callsign = KLM 4805 | plane1_origin = [[Amsterdam Airport Schiphol]]<br />[[Amsterdam]], [[Netherlands]] | plane1_destination = [[Gran Canaria Airport]]<br />[[Gran Canaria]], Canary Islands | plane1_occupants = 248 | plane1_passengers = 234 | plane1_crew = 14 | plane1_fatalities = 248 | plane1_survivors = 0 <!-- the tour guide who did not reboard the plane in Tenerife is NEITHER counted as a survivor, NOR as a passenger. --> | plane2_type = [[Boeing 747#747-100|Boeing 747-121]] | plane2_name = ''Clipper Victor'' | plane2_image = Pan Am Boeing 747-100; N736PA@LHR, April 1972.jpg | plane2_image_upright = 1.2 | plane2_caption = N736PA, the Pan Am Boeing 747-121<br />involved in the accident | plane2_operator = [[Pan American World Airways]] | plane2_tailnum = N736PA | plane2_IATA = PA1736 | plane2_ICAO = PAA1736 | plane2_callsign = CLIPPER 1736 | plane2_origin = {{nowrap|[[Los Angeles International Airport]]}}<br />Los Angeles, United States | plane2_stopover = [[John F. Kennedy International Airport]], [[New York City]], [[U.S.]] | plane2_destination = [[Gran Canaria Airport]]<br />[[Gran Canaria]], [[Canary Islands]] | plane2_occupants = 396 | plane2_passengers = 380 | plane2_crew = 16 | plane2_injuries = 61 | plane2_fatalities = 335 | plane2_survivors = 61 }} The '''Tenerife airport disaster''' occurred on March 27, 1977, when two [[Boeing 747]] passenger jets collided on the [[runway]] at [[Los Rodeos Airport]]<ref>{{cite web|url=https://www.airspacemag.com/history-of-flight/reviews-crash-in-canary-islands-180972227/ |last=Tedeschi |first=Diane |date=June 2019 |title=Crash in the Canary Islands |work=[[Air & Space/Smithsonian|Air & Space Magazine]] |access-date=October 17, 2019}}</ref> (now Tenerife North Airport) on the [[Spain|Spanish]] island of [[Tenerife]].<ref name=hwairerg>{{cite news |url=https://news.google.com/newspapers?id=j9ZVAAAAIBAJ&pg=6267%2C6928131 |work=Eugene Register-Guard |location=(Oregon) |agency=Associated Press |title=580 killed in history's worst air disaster|date=March 28, 1977|page=1A}}</ref><ref name=dpbfadi>{{cite news |url=https://news.google.com/newspapers?id=kNZVAAAAIBAJ&pg=6418%2C7066417|work=Eugene Register-Guard |location=(Oregon) |agency=Associated Press |title=Dutch pilot blamed for air disaster |date=March 29, 1977|page=1A}}</ref> The collision occurred when '''KLM Flight 4805''' ('''IATA:''' KL4805) initiated its [[takeoff]] run during dense fog while '''Pan Am Flight 1736''' ('''IATA:''' PA1736) was still on the runway. The impact and resulting fire killed everyone on board [[KLM]] 4805 and most of the occupants of [[Pan Am]] 1736, with only 61 survivors in the front section of the aircraft. With a total of 583 fatalities, the accident is the [[List of deadliest aircraft accidents and incidents|deadliest accident in aviation history]].<ref name=hwairerg/><ref name=dpbfadi/> A bomb set off by the [[Canary Islands Independence Movement]] at [[Gran Canaria Airport]] had caused many flights to be diverted to Los Rodeos, including the two aircraft involved in the accident. The airport quickly became congested with parked airplanes blocking the only [[taxiway]] and forcing departing aircraft to taxi on the runway instead. Patches of thick fog were drifting across the airfield, so visibility was greatly reduced for pilots and the [[control tower]].<ref name=hwairerg/><ref name=dpbfadi/> The subsequent investigation by Spanish authorities concluded that the primary cause of the accident was the KLM captain's decision to take off in the mistaken belief that a takeoff clearance from [[air traffic control]] (ATC) had been issued.<ref name=ASN/> Dutch investigators placed a greater emphasis on a mutual misunderstanding in radio communications between the KLM crew and ATC,<ref name="dutch_response"/> but ultimately KLM admitted that their crew was responsible for the accident and the airline agreed to financially compensate the relatives of all of the victims.<ref name="KLM responsibility"/> The disaster had a lasting influence on the industry, highlighting in particular the vital importance of using standardized [[phraseology]] in radio communications. Cockpit procedures were also reviewed, contributing to the establishment of [[crew resource management]] as a fundamental part of airline pilots' training.<ref>{{cite web|last=Baron|first=Robert|title=The Cockpit, the Cabin, and Social Psychology|url=http://www.gofir.com/general/crm/index.htm|publisher=Global Operators Flight Information Resource|access-date=May 11, 2011}}</ref> The captain is no longer considered infallible, and combined crew input is encouraged during aircraft operations.<ref>{{cite web|url=http://www.tenerife-information-centre.com/tenerife-airport-disaster.html|title=The Tenerife Airport Disaster – the worst in aviation history|work=The Tenerife Information Centre|access-date=October 29, 2014|archive-date=April 11, 2022|archive-url=https://web.archive.org/web/20220411111410/https://www.tenerife-information-centre.com/tenerife-airport-disaster.html|url-status=live}}</ref> bala tasline thara smith Tenerife was an unscheduled stop for both flights. Their destination was [[Gran Canaria Airport]] (also known as Las Palmas Airport or Gando Airport), serving [[Las Palmas]] on the nearby island of [[Gran Canaria]]. Both islands are part of the [[Canary Islands]], an [[Autonomous communities of Spain|autonomous community of Spain]] located in the [[Atlantic Ocean]] off the southwest coast of [[Morocco]]. === KLM Flight 4805 === [[File:KLM Magazine that contains Captain Jacob Veldhuyzen Van Zanten.jpg|thumb|left|KLM captain Jacob Veldhuyzen van Zanten featured in a 1977 advertisement for the airline.]] KLM Flight 4805 was a [[Air charter|charter flight]] for Holland International Travel Group and had arrived from [[Amsterdam Airport Schiphol]], [[Netherlands]].<ref name="airdisaster.com"/> Its cockpit crew consisted of [[Pilot in command|Captain]] [[Jacob Veldhuyzen van Zanten]] (age 50),<ref>{{cite web|url= http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Official report }}&nbsp;{{small|(5.98&nbsp;MB)}}, section 5.2, p. 38 (PDF p. 41 of 63)"</ref> [[First officer (aeronautics)|First Officer]] Klaas Meurs (42), and [[Flight Engineer]] Willem Schreuder (48). At the time of the accident, Veldhuyzen van Zanten was KLM's chief flight instructor, with 11,700 flight hours, of which 1,545 hours were on the 747. Meurs had 9,200 flight hours, of which 95 hours were on the 747. Schreuder had 17,031 flight hours, of which 543 hours were on the 747. The aircraft was a Boeing 747-206B, registration PH-BUF, named ''Rijn ([[Rhine]])''. The KLM jet was carrying 14 crew members and 235 passengers, including 52 children. Most of the KLM passengers were Dutch; also on board were four Germans, two Austrians, and two Americans. After the aircraft landed at Tenerife, the passengers were transported to the airport terminal. One of the inbound passengers, Robina van Lanschot, who lived on the island with her boyfriend, chose not to re-board the 747, leaving 234 passengers on board.<ref name="Air Disaster Volume 1"/><ref name="NOVA">{{cite web|url=https://www.pbs.org/wgbh/nova/transcripts/3315_planecra.html|title=The Deadliest Plane Crash|date= October 17, 2006|access-date=September 23, 2014 |publisher=PBS}}</ref> === Pan Am Flight 1736 === 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''. It was the first 747 to be delivered to an airline. Of the 380 passengers (mostly of retirement age, but including two children), 14 had boarded in New York, where the crew was also changed. All but five passengers onboard the aircraft were Americans; the non-American passengers were all Canadian nationals.<ref name="nytimeslist">{{cite web |url=https://www.nytimes.com/1977/03/29/archives/list-of-dead-and-survivors-on-pan-american-plane.html |title=List of Dead and Survivors on Pan American Plane |website=The New York Times |url-status=live |date=March 29, 1977 |access-date=February 5, 2023 |archive-url=https://web.archive.org/web/20170102153750/https://www.nytimes.com/1977/03/29/archives/list-of-dead-and-survivors-on-pan-american-plane.html |archive-date=January 2, 2017 }}</ref> The new crew consisted of Captain Victor Grubbs (age 56), First Officer Robert Bragg (age 39), Flight Engineer George Warns (age 46) and 13 flight attendants. At the time of the accident, Grubbs had 21,043 hours of flight time, of which 564 hours were on the 747. Bragg had 10,800 flight hours, of which 2,796 hours were on the 747. Warns had 15,210 flight hours, of which 559 hours were on the 747. This particular aircraft had operated the inaugural 747 commercial flight on January 22, 1970.<ref name="airdisaster.com">{{cite web |url=http://www.airdisaster.com/special/special-pa1736.shtml |title=Special Report: Tenerife |first=Chris |last=Kilroy |website=AirDisaster.com |url-status=dead |archive-url=https://web.archive.org/web/20071018035500/http://www.airdisaster.com/special/special-pa1736.shtml |archive-date=October 18, 2007 }}</ref> On August 2, 1970, in its first year of service, it also became the first 747 to be hijacked: en route between JFK and [[Luis Muñoz Marín International Airport]] in [[San Juan, Puerto Rico]], it was diverted to [[José Martí International Airport]] in [[Havana]], [[Cuba]].<ref name=PanAm>{{cite web |url=http://www.panam.org/the-jet-age/522-a-day-of-firsts-2 |title=A Day of "Firsts" |publisher=Pan Am Historical Foundation |website=PanAm.org |access-date=October 1, 2016 |url-status=live |archive-url=https://web.archive.org/web/20160923184413/https://www.panam.org/the-jet-age/522-a-day-of-firsts-2 |archive-date=September 23, 2016}}</ref> ==Accident== ===Diversion of aircraft to Los Rodeos=== [[File:PH-BUF and N736PA at Los Rodeos Airport in 1977.jpg|thumb|upright=1|''Rijn'' (foreground) and ''Clipper Victor'' (center) at Los Rodeos on the day of the accident.]] Both flights had been routine until they approached the islands. At 13:15, a [[bomb]] planted by the separatist [[Canary Islands Independence Movement]] exploded in the terminal of Gran Canaria Airport, injuring eight people.<ref>{{cite news |url=https://www.nytimes.com/1977/04/02/archives/long-island-opinion-wreck-of-747s-sets-back-cause-of-insurgents-on.html |title=Wreck of 747's Sets Back Cause Of Insurgents on Canary Islands |date=April 2, 1977 |first=James M. |last=Markham |format=from NYT archives |work=[[The New York Times]] }}</ref> Due to the threat of a second bomb, the civil aviation authorities closed the airport temporarily after the initial explosion, and all incoming flights bound for Gran Canaria had been diverted to Los Rodeos, including the two aircraft involved in the disaster.<ref name="ASN">{{cite web |title=ASN Accident Description |url=http://aviation-safety.net/database/record.php?id=19770327-0 |access-date=May 11, 2011 |website=Aviation Safety Network |publisher=Flight Safety Foundation}}</ref> The Pan Am crew indicated that they would prefer to circle in a [[holding pattern]] until landing clearance was given (they had enough fuel to safely stay in the air for two more hours), but they were ordered to divert to Tenerife.<ref name=TIC>{{cite web|url=http://www.tenerife-information-centre.com/tenerife-airport-disaster.html|title=The Tenerife Airport Disaster – the worst in aviation history|work=tenerife information centre|date=March 27, 1977|access-date=April 11, 2017}}</ref> Los Rodeos was a regional airport that could not easily accommodate all of the traffic diverted from Gran Canaria, which included five large airliners.<ref>{{Cite book|url=https://books.google.com/books?id=UQwU80HzPEkC&pg=PA40|title=The Age of Catastrophe: Disaster and Humanity in Modern Times|last=Ebert|first=John David|publisher=McFarland|year=2012|isbn=978-0-7864-7142-3|page=41|quote=Five large planes had been diverted to Las Rodeos, ...}}</ref> The airport had only one [[runway]] and one major [[taxiway]] running parallel to it, with four short taxiways connecting the two. While waiting for Gran Canaria airport to reopen, the diverted airplanes took up so much space that they had to park on the long taxiway, making it unavailable for the purpose of [[taxiing]]. Instead, departing aircraft needed to taxi along the runway to position themselves for takeoff, a procedure known as a [[backtaxi]] or backtrack.<ref name=ASN/> The authorities reopened Gran Canaria airport once the bomb threat had been contained. The Pan Am plane was ready to depart from Tenerife, but access to the runway was obstructed by the KLM plane and a refueling vehicle; the KLM captain had decided to fully refuel at Los Rodeos instead of Las Palmas, apparently to save time. The Pan Am aircraft was unable to maneuver around the refueling KLM in order to reach the runway for takeoff, due to a lack of safe clearance between the two planes, which was just {{convert|12|ft|order=flip|sp=us}}.<ref name="Air Disaster Volume 1">{{cite book |title=Air Disaster, Volume 1 |first=Macarthur |last=Job |author-link=Macarthur Job |year=1995 |pages=164–180 |isbn=978-1875671113 |publisher=[[Chronicle Publishing Company|Motorbooks International]] }}</ref> The refueling took about 35 minutes, after which the passengers were brought back to the aircraft. The search for a missing Dutch family of four, who had not returned to the waiting KLM plane, delayed the flight even further. Robina van Lanschot,<ref>{{Cite news|last=ten Voorde|first=Gerard|date=March 21, 2017|title=Enige overlevende KLM-toestel vliegramp Tenerife blikt na veertig jaar terug|trans-title=Only surviving KLM plane Tenerife plane crash looks back after forty years|url=https://www.rd.nl/artikel/702799-enige-overlevende-klm-toestel-vliegramp-tenerife-blikt-na-veertig-jaar-terug|access-date=July 24, 2021|work=Reformatorisch Dagblad|language=nl}}</ref> a tour guide, had chosen not to reboard for the flight to Las Palmas, because she lived on Tenerife and thought it impractical to fly to Gran Canaria only to return to Tenerife the next day. She was therefore not on the KLM plane when the accident happened, and was the only survivor of those who flew from Amsterdam to Tenerife on Flight 4805. === Taxiing and takeoff preparations === The tower instructed the KLM plane to taxi down the entire length of the runway and then make a 180° turn to get into takeoff position.<ref>{{cite web|url= http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Official report }}&nbsp;{{small|(5.98&nbsp;MB)}}, p. 2 (PDF p. 5 of 63)</ref> While the KLM was backtaxiing on the runway, the controller asked the flight crew to report when it was ready to copy the [[Instrument flight rules#Separation and clearance|ATC clearance]]. Because the flight crew was performing the checklist, copying the clearance was postponed until the aircraft was in takeoff position.<ref>{{cite web|url= http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Official report }}&nbsp;{{small|(5.98&nbsp;MB)}}, pp. 3–4 (PDF pp. 6–7 of 63)</ref> [[File:Map Tenerife Disaster.svg|left|thumb|upright=1.8|Simplified map of runway, taxiways, and aircraft. The red star indicates the location of impact. Not to scale.]] 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.<ref>{{cite web|url= http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Official report }}&nbsp;{{small|(5.98&nbsp;MB)}}, p. 3 (PDF p. 6 of 63)</ref> The crew successfully identified the first two taxiways (C-1 and C-2), but their discussion in the cockpit indicated that they had not sighted the third taxiway (C-3), which they had been instructed to use.<ref>{{cite web|url= http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Official report }}&nbsp;{{small|(5.98&nbsp;MB)}}, pp. 56–57 (PDF pp. 59–60 of 63)</ref> 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).<ref>{{cite web|url= http://www.project-tenerife.com/engels/PDF/los_rodeos_anexo6.pdf |archive-url=https://web.archive.org/web/20060509181028/http://www.project-tenerife.com/engels/PDF/los_rodeos_anexo6.pdf |archive-date=May 9, 2006 |url-status=live |title=Official report, annex 6 }}</ref> The angle of the third taxiway would have required the plane to perform a 148° turn, which would lead back toward the still-crowded main [[Airport apron|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, similar to a mirrored letter "Z". Taxiway C-4 would have required two 35° turns. A study carried out by the [[Air Line Pilots Association, International|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".<ref>{{cite web|url=http://www.project-tenerife.com/engels/PDF/alpa.pdf |title=ALPA report on the crash |url-status=dead |archive-url=https://web.archive.org/web/20110715122130/http://www.project-tenerife.com/engels/PDF/alpa.pdf |archive-date=July 15, 2011 |df=mdy-all }}&nbsp;{{small|(2.70&nbsp;MB)}}, p. 19 (PDF p. 23 of 97)</ref> The official report from the Spanish authorities explained 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.<ref>{{cite web|url= http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Official report }}&nbsp;{{small|(5.98&nbsp;MB)}}, p. 46 (PDF p. 49 of 63)</ref> === Weather conditions at Los Rodeos === Los Rodeos airport is at {{convert|633|m|sp=us}} above [[sea level]], which gives rise to weather conditions that differ from those at many other airports. Clouds at {{convert|600|m|abbr=on}} 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 legal minimum the next. The collision took place in a high-density cloud.<ref>{{cite web|url=http://www.project-tenerife.com/engels/PDF/alpa.pdf |title=ALPA report on the crash |url-status=dead |archive-url=https://web.archive.org/web/20110715122130/http://www.project-tenerife.com/engels/PDF/alpa.pdf |archive-date=July 15, 2011 |df=mdy-all }}&nbsp;{{small|(2.70&nbsp;MB)}}, p. 8 (PDF p. 12 of 97)</ref> 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 {{convert|500|m|abbr=on}}. Shortly after they turned onto the runway it decreased to less than {{convert|100|m|abbr=on}}.<ref>{{cite web|url=http://www.project-tenerife.com/engels/PDF/alpa.pdf |title=ALPA report on the crash |url-status=dead |archive-url=https://web.archive.org/web/20110715122130/http://www.project-tenerife.com/engels/PDF/alpa.pdf |archive-date=July 15, 2011 |df=mdy-all }}&nbsp;{{small|(2.70&nbsp;MB)}}, p. 11 (PDF p. 15 of 97)</ref> Meanwhile, the KLM plane was still in good visibility, but with clouds blowing down the runway towards them. The aircraft completed its 180-degree turn in relatively clear weather and lined up on Runway 30. The next cloud was {{convert|900|m|abbr=on}} down the runway and moving towards the aircraft at about {{convert|12|kn|mph km/h}}.<ref>{{cite web|url=http://www.project-tenerife.com/engels/PDF/alpa.pdf |title=ALPA report on the crash |url-status=dead |archive-url=https://web.archive.org/web/20110715122130/http://www.project-tenerife.com/engels/PDF/alpa.pdf |archive-date=July 15, 2011 |df=mdy-all }}&nbsp;{{small|(2.70&nbsp;MB)}}, p. 12 (PDF p. 16 of 97)</ref> === Communication misunderstandings === {| class="wikitable collapsible collapsed floatright" |- | style="width: 300pt;"|'''Cockpit and ATC tower communications'''<ref name="final dutch report"/> <ref>Additional references:<br />{{Cite web|url=https://www.1001crash.com/index-page-tenerife-lg-2.html|title=The Tenerife crash – March 27th, 1977|website=1001crash.com|access-date=June 28, 2016}}<br />{{cite web|url=http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Copy of the Spanish Report |website=Project-Tenerife.com |date=November 16, 1978 |access-date=May 5, 2012}}<br />{{cite web|url=http://www.airdisaster.com/cvr/tenetr.shtml |title=Cockpit Voice Recorders: Transcripts: KLM 4805 |website=AirDisaster.com |access-date=May 5, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120420202328/http://www.airdisaster.com/cvr/tenetr.shtml |archive-date=April 20, 2012 }}<br />{{cite book|first=Shari S. |last=Krause|title=Aircraft Safety: Accident Investigations, Analyses, & Applications |edition=2nd|url=https://books.google.com/books?id=YKSwwwyWaT0C&pg=PA205|year=2003|publisher=McGraw-Hill|isbn=978-0-07-140974-2|page=205}}<br />{{cite web|url=https://www.pbs.org/wgbh/nova/space/final-eight-minutes.html |title=NOVA: The Final Eight Minutes |first=Lexi |last=Krock |website=PBS Online |date=October 17, 2006 |access-date=May 5, 2012}}<br />{{cite book|url=https://books.google.com/books?id=KY-MBUeQoZEC&q=pan+am+there+he+is&pg=SA1-PA67 |title=JAR Professional Pilot Studies | isbn=978-0-9681928-2-5 |last1=Croucher |first1=Phil |publisher=Electrocution Technical Publishers |year=2005 |page=67}}<br />{{cite web |title=Official CVR transcript |url=http://project-tenerife.com/engels/PDF/Anexonumero5.pdf |archive-url=https://web.archive.org/web/20060506020118/http://www.project-tenerife.com/engels/PDF/Anexonumero5.pdf |archive-date=May 6, 2006 |url-status=live |website=project-tenerife.com |access-date=June 4, 2021 }}</ref> |- | style="width: 300pt;"|These communications are taken from the [[Flight recorder#Cockpit voice recorder|cockpit voice recorders]] of both aircraft, as well as from the Tenerife control tower's tapes. 1705:36–1706:50 <blockquote> 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. 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, right turn out zero four zero until intercepting the three two five. We are now at take-off [or "uh..taking off"]. 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 radio interference.] 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 is not heard completely clearly by the KLM crew due to radio interference.] 1706:25.5 :'''TENERIFE TOWER''' Ah, Papa Alpha one seven three six, report the runway clear. 1706:29.6 :'''PAN AM (RADIO)''' OK, we'll report when (we are) clear. 1706:31.7 :'''TENERIFE TOWER''' Thank you. [This was the last radio communication involving the two aircraft. Everything that follows is intra-cockpit communication amongst the respective crews.] </blockquote> 1706:32–1706:40 <blockquote> 1706:32.1 :'''PAN AM CAPTAIN''' Let's get the hell 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 an hour and a half, that bastard. Now he's in a rush. 1706:32.4 :'''KLM FLIGHT ENGINEER''' ''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. 1706:34.7 :'''KLM 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)] </blockquote> 1706:40–1706:50 <blockquote> 1706:40.5 :[Pan Am captain sees the KLM's landing lights 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 speeds#V1 definitions|V-1]]. 1706:44.0 :[PH-BUF (KLM 4805) starts [[Rotation (aeronautics)|rotation]].] 1706:47.4 :'''KLM CAPTAIN''' Oh shit! 1706:48 :'''PAN AM CAPTAIN''' Oh god damn! : : :1706:49.7 : : : : : : : :PH-BUF (KLM 4805) records sound of collision. 1706:50 :N736PA (Pan Am 1736) records sound of collision. </blockquote> |} Immediately after lining up, the KLM captain advanced the throttles and the aircraft started to move forward.<ref>Official report, p. 48</ref><!--(a standard procedure known as "spool-up", to verify that the engines are operating properly for takeoff)--><!--This isn't in the source. It may or may not be the true, but a power-check would normally be conducted with the brakes on, yet the aircraft started to move--> Meurs advised him that ATC clearance had not yet been given and Veldhuyzen van Zanten responded: "No, I know that. Go ahead, ask." Meurs then radioed the tower that they were "ready for takeoff" and "waiting for our ATC clearance". ATC radioed the KLM aircraft (addressing them by the wrong call sign), providing instructions that specified the route that the aircraft was to follow after takeoff, but did not clear them for takeoff. Meurs read the flight clearance back to the controller, completing the readback with the statement: "We are now at takeoff."<ref name=ASN/> Veldhuyzen van Zanten interrupted the co-pilot's readback with the comment, "We're going."<ref name=ASN/> The controller, who could not see the runway due to the fog, initially responded with "OK" (terminology that 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 takeoff, I will call you",<ref name=ASN/> indicating that he had not intended the instruction to be interpreted as a takeoff clearance.<ref>{{cite journal|url=http://cf.alpa.org/internet/alp/2000/aug00p18.htm |title=Remembering Tenerife |first=Gerard M. |last=Bruggink |journal=Air Line Pilot |date=August 2000|page= 18 |access-date=February 24, 2014 |archive-url=https://web.archive.org/web/20060513193139/http://cf.alpa.org/internet/alp/2000/aug00p18.htm |archive-date=May 13, 2006 |url-status=dead}}</ref> A simultaneous radio call from the Pan Am crew caused mutual [[interference (communication)|interference]] on the radio frequency, which was audible in the KLM cockpit as a three-second-long shrill 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.<ref>{{cite news|url=http://www.salon.com/2002/03/28/heterodyne/singleton/ |archive-url=https://archive.today/20130201162840/http://www.salon.com/2002/03/28/heterodyne/singleton/ |url-status=dead |archive-date=February 1, 2013 |title=Air travel's communications killer |work=Salon.com |date=March 28, 2002 }}</ref> 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 [[surface movement radar|ground radar]].<ref name=ASN/> After the KLM plane had started its takeoff roll, the tower instructed the Pan Am crew to "report the runway clear." The Pan Am crew replied: "OK, will 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.<ref name="final dutch report">{{cite web |title=Final Report |url=http://www.project-tenerife.com/nederlands/PDF/finaldutchreport.pdf |publisher=Netherlands Aviation Safety Board |access-date=July 12, 2021 |page=46 |language=English }}</ref> === Collision === [[File:Vliegtuigmotor van één van de verongelukte jumbojets, Bestanddeelnr 929-1008 (cropped).jpg|thumb|Engine wreckage]]According to the [[Flight recorder#Cockpit voice recorder|cockpit voice recorder]] (CVR), the Pan Am captain 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 aircraft was approaching at takeoff speed, Captain Grubbs exclaimed, "Goddamn, that son-of-a-bitch is coming!", while first officer Robert Bragg yelled, "Get off! Get off! Get off!"<ref>{{Citation |title=What REALLY Caused the Tenerife Airport Disaster?! The WORST Aviation Accident in History |url=https://www.youtube.com/watch?v=2d9B9RN5quA |language=en |access-date=February 10, 2023}}</ref> Grubbs applied full power to the throttles and made a sharp left turn towards the grass in an attempt to avoid the impending collision.<ref name=ASN/> By the time the KLM pilots saw the Pan Am aircraft, they were already moving too fast to stop. In desperation, the pilots prematurely [[Rotation (aeronautics)|rotated]] the aircraft nose upward and attempted to clear the Pan Am by lifting off, causing a {{convert|22|m|ft|abbr=on}} [[tailstrike]].<ref name="ASN" /> The KLM 747 was within {{convert|100|m|abbr=on}} of the Pan Am and moving at approximately {{convert|140|knot|km/h mph}} when it left the ground. Its nose landing gear cleared the Pan Am, but its left-side engines, lower fuselage, and main landing gear struck the upper right side of the Pan Am's fuselage,<ref name="Air Disaster Volume 1"/> 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, but the impact 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 plane immediately went into a stall, rolled sharply, and hit the ground approximately {{convert|150|m|-2|abbr=on}} past the collision, sliding down the runway for a further {{convert|300|m|-2|abbr=on}}. The full load of fuel, which had caused the earlier delay, ignited immediately into a fireball that could not be subdued for several hours. One of the 61 survivors of the Pan Am flight 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."<ref>{{cite web|url=https://www.upi.com/Archives/Audio/Events-of-1977/Terrorism |title=1977 Year in Review: Terrorism |website=UPI.com |date=1977 |access-date=July 19, 2021 |url-status=live |archive-url=https://web.archive.org/web/20120104211042/http://www.upi.com/Audio/Year_in_Review/Events-of-1977/Terrorism/12361881614363-4/ |archive-date=January 4, 2012}}</ref> [[File:Het verongelukte KLM-toestel De Rijn, Bestanddeelnr 929-1003 (cropped).jpg|thumb|Burned out wreckage]] Veldhuyzen van Zanten was KLM's chief of flight training and one of their most senior pilots. About two months before the accident, he had conducted the Boeing 747 qualification check on the co-pilot of Flight 4805.<ref name="NOVA" /> His photograph was used for publicity materials such as magazine advertisements, including the inflight magazine on board PH-BUF.<ref name="Air Disaster Volume 1" /><ref>{{cite web|title=Advertisement: KLM. From the people who made punctuality possible.|url=http://www.project-tenerife.com/nederlands/fotos/bemanning/1.jpg|url-status=live|archive-url=https://web.archive.org/web/20120121040148/http://www.project-tenerife.com/nederlands/fotos/bemanning/1.jpg|archive-date=January 21, 2012|access-date=December 21, 2012|website=Project-Tenerife.com}}</ref> KLM had suggested initially that Veldhuyzen van Zanten should help with the investigation, unaware that he was the captain who had been killed in the accident.<ref name="Reijnoudt">{{cite book|last1=Reijnoudt|first1=Jan|title=Tragedie op Tenerife: de grootste luchtramp, optelsom van kleine missers|last2=Sterk|first2=Niek|date=2002|publisher=Kok|isbn=978-9043504522|trans-title=Tenerife tragedy: biggest air disaster, sum of small mistakes}}</ref> == Victims == Both airplanes were destroyed in the collision. All 248 passengers and crew aboard the KLM plane died, as did 335 passengers and crew aboard the Pan Am plane,<ref>{{cite web |url=http://www.airsafe.com/events/airlines/klm.htm |title=KLM plane crashes |website=AirSafe.com |access-date=October 12, 2007}}</ref> primarily due to the fire and explosions resulting from the fuel spilled and ignited in the impact. The other 61 passengers and crew aboard the Pan Am aircraft survived. There were initially 70 survivors, but 9 passengers later died of their injuries.<ref>{{cite web|url= http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Official report }}&nbsp;{{small|(5.98&nbsp;MB)}}, section 1.2.2, p. 5 (PDF p. 9 of 63)"</ref> Among the survivors were 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 means 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 hundreds of meters away in the thick fog and smoke. Eventually, most of the survivors on the wing dropped to the ground below.<ref name="Air Disaster Volume 1" /> === Notable fatalities === *[[Jacob Veldhuyzen van Zanten]], chief flight instructor for KLM and the captain of the KLM flight.<ref name="Reijnoudt"/> *[[Eve Meyer]], a [[Pinup girl|pin-up model]], film actress and producer and second wife of film director [[Russ Meyer]], was on the Pan Am flight.<ref>{{cite web|title=Passenger list of the PanAm|url=http://www.project-tenerife.com/engels/panampas.htm|access-date=February 10, 2016|publisher=ProjectTenerife.com}}</ref> *[[A. P. Hamann]], the former [[city manager]] of [[San Jose, California]], was on the Pan Am flight.<ref>{{cite web|date=January 23, 2006|title=San Jose Inside – Dutch Hamann – Part 2|url=http://www.sanjoseinside.com/sji/blog/entries/dutch_hamann1/|access-date=May 5, 2012|publisher=Sanjoseinside.com}}</ref> == Aftermath == [[File:Het verongelukte KLM-toestel De Rijn, Bestanddeelnr 929-1004 (cropped).jpg|thumb|Wreckage of the [[KLM]]'s [[vertical stabilizer]]]] The following day, the Canary Islands Independence Movement, responsible for the bombing at Gran Canaria that started the chain of events that led to the disaster, denied responsibility for the accident.<ref>{{cite news |title=Canary Island Separatist Says Group Planted Bomb But Did Not Cause Crash |url=https://www.nytimes.com/1977/03/28/archives/canary-island-separatist-says-group-planted-bomb-but-did-not-cause.html |access-date=December 20, 2018 |work=[[The New York Times]] |agency=[[Agence France-Presse]] |date=March 28, 1977}}</ref> Los Rodeos Airport was closed to all [[fixed-wing aircraft|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 3-hour boat ride from Las Palmas.<ref>{{cite news|url=https://chicagotribune.newspapers.com/search/#query=Experts+converge+on+Canaries+to+probe+plane+crash |title=Experts converge on Canaries to probe plane crash |newspaper=[[Chicago Tribune]] |date=March 29, 1977 |page=1 |url-access=subscription |access-date=June 29, 2020}}</ref> The first aircraft that was able to land was a [[United States Air Force|U.S. Air Force]] [[Lockheed C-130 Hercules|C-130]] transport, which landed on the airport's main taxiway at 12:50 on March 29. The C-130 was arranged by Lt. Col Dr. James K. Slaton, who arrived before the crash investigators and started a [[triage]] of surviving passengers. Slaton was dispatched from [[Torrejon Air Base]] just outside of [[Madrid|Madrid, Spain]]. Slaton, a flight surgeon attached to the [[613th Tactical Fighter Squadron]], worked with local medical staff and remained on scene until the last survivor was airlifted to awaiting medical facilities. The C-130 transported all surviving and injured passengers from Tenerife airport to Las Palmas; many of the injured were taken from there to other Air Force bases in the U.S. for further treatment.<ref name=ergupiacfh>{{cite news|url=https://news.google.com/newspapers?id=kdZVAAAAIBAJ&pg=6176%2C7238622 |work=Eugene Register-Guard |location=(Oregon) |agency=UPI |title=Air crash victims flown home |date=March 30, 1977 |page=1A}}</ref><ref>{{Cite web|url=http://cdnc.ucr.edu/cgi-bin/cdnc?a=d&d=DS19770329.2.2|title=Desert Sun 29 March 1977 — California Digital Newspaper Collection|website=cdnc.ucr.edu|access-date=June 28, 2016}}</ref> Spanish Army soldiers were tasked with clearing crash wreckage from the runways and taxiways.<ref name=":0" /> By March 30, a small plane shuttle service was approved, but large jets still could not land.<ref name=":0">{{Cite web|url=https://www.newspapers.com/image/21933329/|title=30 Mar 1977, Page 4 - The Naples Daily News|website=Newspapers.com|access-date=June 19, 2016}}</ref> Los Rodeos was fully reopened on April 3, after wreckage had been fully removed and engineers had repaired the airport's runway.<ref>{{Cite web|url=http://eresources.nlb.gov.sg/newspapers/Digitised/Page/newnation19770404-1.1.5 |title=Crash airport open again |newspaper=New Nation (Singapore) |publisher=[[National Library Board|NLB]] |date=April 4, 1977 |page=5 |access-date=June 28, 2016}}</ref> == Investigation == [[File:Eén de twee verongelukte toestellen, Bestanddeelnr 929-1006 (cropped).jpg|thumb|Wreckage of the [[Pan Am]] Boeing 747]] The accident was investigated by Spain's [[Civil Aviation Accident and Incident Investigation Commission]] (CIAIAC).<ref name=ASN /> About 70 personnel were involved in the investigation, including representatives from the United States, the Netherlands<ref>{{cite web|url=https://www.pbs.org/wgbh/nova/planecrash/minutes.html |title=The Deadliest Plane Crash - The Final Eight Minutes |work=[[Nova (American TV program)|Nova]] |access-date=October 17, 2019}}</ref> and the two airline companies.<ref>{{Cite web|title=B742 / B741, Tenerife Canary Islands Spain, 1977 - SKYbrary Aviation Safety|url=https://www.skybrary.aero/index.php/B742_/_B741,_Tenerife_Canary_Islands_Spain,_1977|access-date=June 3, 2021|website=www.skybrary.aero|date=April 5, 2021}}</ref> Facts showed that there had been misinterpretations and false assumptions before the accident. Analysis of the CVR transcript showed that the KLM pilot thought that he had been cleared for takeoff, while the Tenerife control tower believed that the KLM 747 was stationary at the end of the runway, awaiting takeoff clearance. === Probable cause === The investigation concluded that the fundamental cause of the accident was that Veldhuyzen van Zanten attempted to take off without clearance. The investigators suggested the reason for this was a desire to leave as soon as possible in order to comply with KLM's duty-time regulations (which went in place earlier that year) and before the weather deteriorated further. Other major factors contributing to the accident were: * The sudden fog greatly limited visibility and the control tower and the crews of both planes were unable to see one another. * Interference from simultaneous radio transmissions made hearing messages difficult. The following factors were considered contributing but not critical: * The 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 did not leave the runway at the third exit as instructed. * The airport was forced to accommodate a great number of large aircraft rerouted by the terrorist incident, disrupting the normal use of taxiways.<ref name=official_report>{{cite web|url= http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Official report }}&nbsp;{{small|(5.98&nbsp;MB)}}, pp. 61–62</ref> === Dutch response === [[File:Vlaggen_halfstok_voor_het_KLM-hoofdkantoor_te_Amstelveen,_Bestanddeelnr_929-0961.jpg|thumb|Flags at half-staff in KLM's headquarters in Amstelveen, following the disaster (1977)]] The Dutch authorities were reluctant to accept the Spanish report blaming the KLM captain for the accident.<ref>{{cite journal|last=Curran |first=William J. |date=November 3, 1977 |title=The Medicolegal Lessons of the Tenerife Disaster |journal=[[The New England Journal of Medicine]] |volume=297 |issue=18 |pages=986–987 |doi=10.1056/NEJM197711032971806 |pmid=909545 |issn=0028-4793 }}</ref> The Netherlands Department of Civil Aviation published a response that, while accepting that the KLM captain 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, including the KLM cockpit crew, the Pan Am cockpit crew, and the controller; * Sounds on the CVR suggested that during the accident the Spanish control tower crew had been listening to a [[Association football|football]] match on the radio and may have been distracted;<ref>{{cite web |title=Final report and comments of the Netherlands Aviation Safety Board |url=http://www.project-tenerife.com/nederlands/PDF/finaldutchreport.pdf |url-status=live |archive-url=https://web.archive.org/web/20070927003827/http://www.project-tenerife.com/nederlands/PDF/finaldutchreport.pdf |archive-date=September 27, 2007 |website= |publisher=Netherlands Department of Civil Aviation |pages=60–61 (PDF pp. 40–41) |via=Project-Tenerife.com}}</ref> * 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 Grubbs and 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.<ref name="dutch_response">{{cite web |title=Dutch comments on the Spanish report |url=http://www.project-tenerife.com/engels/PDF/Dutch_comments.PDF |url-status=live |archive-url=https://web.archive.org/web/20060921122454/http://www.project-tenerife.com/engels/PDF/Dutch_comments.PDF |archive-date=September 21, 2006 |website= |publisher=Netherlands Department of Civil Aviation |via=Project-Tenerife.com}}</ref><ref name="Black Box">{{cite book|title=Black Box: Inside the World's Worst Air Crashes |first=Nicholas |last=Faith |publisher=Monday Books |isbn=978-1906308469 |date=August 2012 |orig-year=1996 |pages=176–178}}</ref> Although the Dutch authorities were initially reluctant to blame Veldhuyzen van Zanten and his crew,<ref name="dutch_response"/><ref name="Black Box"/> the airline ultimately accepted responsibility for the accident. KLM paid the victims' families compensation ranging between $58,000 and $600,000 (or ${{inflation|US|58000|1977|r=-3|fmt=c}} to ${{inflation|US|.6|1977|r=1}} million today, adjusted for inflation).<ref name="KLM responsibility">{{cite web | url=http://www.project-tenerife.com/engels/howklmaccept.htm | title=How KLM accepted their responsibility for the accident | website=Project-Tenerife.com |archive-url=https://web.archive.org/web/20070822232022/http://www.project-tenerife.com/engels/howklmaccept.htm |archive-date=August 22, 2007 |url-status=live}}</ref> The sum of settlements for property and damages was $110 million (or ${{inflation|US|110|1977|r=0}} million today),<ref>''[[The Washington Post]]'', March 25, 1980</ref> an average of $189,000 (or ${{inflation|US|189000|1977|r=-3|fmt=c}} today) per victim, due to limitations imposed by European Compensation Conventions in effect at the time. === Speculations === This was one of the first accident investigations to include a study into the contribution of "human factors".<ref name="alpa22a">{{cite web|url=http://www.project-tenerife.com/engels/PDF/alpa.pdf |title=ALPA report on the crash |url-status=dead |archive-url=https://web.archive.org/web/20110715122130/http://www.project-tenerife.com/engels/PDF/alpa.pdf |archive-date=July 15, 2011 |df=mdy-all }}&nbsp;{{small|(2.70a&nbsp;MB)}}, p. 2 (PDF p. 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."</ref> These included: * Veldhuyzen van Zanten, a KLM training captain and instructor for over ten years working on simulators regularly, had not flown on regular routes for twelve weeks prior to the accident.<ref>{{cite journal|last1=Weick|first1=Karl E.|title=The Vulnerable System: An Analysis of the Tenerife Air Disaster|journal=Journal of Management|date=September 1, 1990|volume=16|issue=3|pages=571–593|doi=10.1177/014920639001600304|language=en|url=https://deepblue.lib.umich.edu/bitstream/2027.42/68716/2/10.1177_014920639001600304.pdf |archive-url=https://web.archive.org/web/20170821154722/http://deepblue.lib.umich.edu/bitstream/2027.42/68716/2/10.1177_014920639001600304.pdf |archive-date=August 21, 2017 |url-status=live|hdl=2027.42/68716|s2cid=145765387|hdl-access=free}}</ref> * The KLM flight crew, including Veldhuyzen van Zanten, were concerned about exceeding their maximum legally allowable on-duty hours for the day, which Dutch law had recently tightened. This influenced Veldhuyzen van Zanten's decision to refuel at Tenerife for the flight to Amsterdam after as brief a stop as possible at Las Palmas. * The apparent hesitation of the flight engineer and the first officer to challenge Veldhuyzen van Zanten further. The official investigation suggested that this might have been due to not only the captain's seniority in rank but also his being one of the most respected pilots working for the airline.<ref name="Air Disaster Volume 1"/><ref>{{cite web|url= http://www.project-tenerife.com/engels/PDF/Tenerife.pdf |title=Official report }}&nbsp;{{small|(5.98&nbsp;MB)}}, section 5.2, p. 38 (PDF p. 41 of 63): "...&nbsp;these circumstances could have induced the co-pilot not to ask any questions, assuming that his captain was always right"</ref> 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 officers and believes this explanation to be inconsistent with his knowledge of their personalities. The first officer had intervened when Veldhuyzen van Zanten first opened the throttles, but had then failed to do so on the second occasion. Although the flight engineer had indeed asked the captain whether or not the Pan Am was clear of the runway, he seemed reassured by the captain's answer. The co-pilots had clearly challenged the captain's decisions, but were not insistent enough to convince him to abort the attempted takeoff.<!--But does he offer an alternative explanation?--><ref name=book>{{Cite book | last = Bartelski | first = Jan | title = Disasters in the air: mysterious air disasters explained | publisher = Airlife | year = 2001 | url = https://archive.org/details/disastersinairmy0000bart | isbn = 978-1-84037-204-5 | quote = <!-- As far as the allegations that co-pilots would not have the nerve to stand up to Veldhuyzen 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. Veldhuyzen 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 Veldhuyzen'' He had learnt much about cockpit management by representing KLM at an [[International Air Transport Association|IATA]] Conference in [[Istanbul]] and was trying to put this into practice<br />...<br />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 Veldhuyzen van Zanten. Both complemented each other in personalities as well as in their operational background. What Veldhuyzen 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 Veldhuyzen van Zanten from opening the throttles --> | url-access = registration }}</ref> * The flight engineer was the only member of the KLM's flight crew to react to the control tower's instruction to "report the runway clear"; this might have been due to his having completed his pre-flight checks, whereas his colleagues were experiencing an increased workload, just as the visibility worsened.<ref name="alpa22">{{cite web|url=http://www.project-tenerife.com/engels/PDF/alpa.pdf |title=ALPA report on the crash |url-status=dead |archive-url=https://web.archive.org/web/20110715122130/http://www.project-tenerife.com/engels/PDF/alpa.pdf |archive-date=July 15, 2011 |df=mdy-all }}&nbsp;{{small|(2.70&nbsp;MB)}}, p. 22 (PDF p. 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."</ref> * The ALPA study group concluded that the KLM crew did not realize that the transmission "Papa Alpha One Seven Three Six, report the 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. Previously, the Pan Am had been called "Clipper One Seven Three Six", using its proper call-sign.<ref name="alpa22b">{{cite web|url=http://www.project-tenerife.com/engels/PDF/alpa.pdf |title=ALPA report on the crash |website=Project-Tenerife.com |url-status=dead |archive-url=https://web.archive.org/web/20110715122130/http://www.project-tenerife.com/engels/PDF/alpa.pdf |archive-date=July 15, 2011 |df=mdy-all }}&nbsp;{{small|(2.70&nbsp;MB)}}, p. 22 (PDF p. 26 of 97). "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)."</ref> The extra fuel taken on by the KLM added several factors: * Takeoff was delayed by an extra 35 minutes, allowing time for the fog to settle in; * More than 45 [[tonnes]] of additional weight was added to the aircraft,<ref>{{cite web|url=http://www.fomento.es/MFOM/LANG_CASTELLANO/DIRECCIONES_GENERALES/ORGANOS_COLEGIADOS/CIAIAC/PUBLICACIONES/HISTORICOS/LOSRODEOS/los_rodeos_2_1.htm|title=CIAIAC {{!}} Publications {{!}} Relevant reports {{!}} A-102/1977 and A-103/1977 2.1 Analysis|website=fomento.es|publisher=[[Government of Spain]]|language=es|archive-url=https://web.archive.org/web/20090412154318/http://www.fomento.es/MFOM/LANG_CASTELLANO/DIRECCIONES_GENERALES/ORGANOS_COLEGIADOS/CIAIAC/PUBLICACIONES/HISTORICOS/LOSRODEOS/los_rodeos_2_1.htm|archive-date=April 12, 2009|url-status=dead}} This Spanish report states 55,500 liters of [[jet fuel]]; based on a density of 0.8705 kg/L, that would weigh 45 [[Tonne|metric tons]] or 49 [[Ton|US tons]].</ref> increasing the takeoff distance and making it more difficult to clear the Pan Am when taking off; * The increased severity of the fire caused by the additional fuel led ultimately to the deaths of all those on board.<ref>{{Citation |url=https://www.pbs.org/wgbh/nova/space/deadliest-plane-crash.html |title=The Deadliest Plane Crash - transcript|quote=The 55 tons of fuel the Dutch plane had taken on creates a massive fireball that seals the fate of everyone onboard |publisher=NOVA }}</ref><ref>{{cite web|url=http://www.crossroadstoday.com/content/news/international/story/Worlds-deadliest-airline-disaster-occurred-36-yea/mRW2KWYC7UitRHn5UWeXLw.cspx |title=World's deadliest airline disaster occurred 36 years ago today |date=March 27, 2013 |quote=The full load of new fuel ignited immediately. |work=Crossroads Today |publisher=Saga Broadcasting, LLC |archive-url=https://archive.today/20130731104549/http://www.crossroadstoday.com/content/news/international/story/Worlds-deadliest-airline-disaster-occurred-36-yea/mRW2KWYC7UitRHn5UWeXLw.cspx |archive-date=July 31, 2013 |url-status=dead}}</ref> == Legacy == [[File:De_kisten_van_de_slachtoffers_van_de_ramp,_Bestanddeelnr_929-1123.jpg|thumb|upright=1.2|Funeral service for the victims of Tenerife airport disaster at Amsterdam Airport Schiphol (April 6, 1977)]] 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 [[Radiotelephony procedure|standard phrases]] and a greater emphasis on English as a common [[working language]].<ref name=TIC /> Air traffic instruction must not be acknowledged solely with a colloquial phrase such as "OK" or even "[[Voice procedure|Roger]]" (which simply means the last transmission was received),<ref>CAP 413 Radio Telephony Manual (Edition 15), chapter 2 page 6</ref> but with a readback of the key parts of the instruction, to show mutual understanding. The word "takeoff" is now spoken only when the actual takeoff clearance is given, or when canceling that same clearance (i.e., "cleared for takeoff" or "cancel takeoff clearance"). Until that point, aircrew and controllers should use the word "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".<ref>CAP 413 Radio Telephony Manual (Edition 15), chapter 4, page 6, paragraph 1.7.10</ref> [[Cockpit]] procedures were also changed after the accident. Hierarchical relations among crew members were played down, and greater emphasis was placed on team decision-making by mutual agreement. Less experienced flight crew members were encouraged to challenge their captains when they believed something to be incorrect, and captains were instructed to listen to their crew and evaluate all decisions in light of crew concerns. This course of action was later expanded into what is known today as [[crew resource management]] (CRM), which states that all pilots, no matter how experienced they are, are allowed to contradict each other. This was a problem in the crash when the Flight Engineer asked if they were not clear, but Veldhuyzen van Zanten (with over 11,000 hours flown) said that they were obviously clear and the Flight Engineer decided that it was best not to contradict the captain. CRM training has been mandatory for all airline pilots since 2006.<ref>{{cite book |last1=Alexander |first1=David |title=Never Wait for the Fire Truck: How the Worlds Deadliest Plane Crash Changed My Life and Yours |date=2015 |publisher=Createspace Independent |location=New York |isbn=978-0692471876 }}{{cite news|title=Tenerife Disaster – 27 March 1977: The Utility of the Swiss Cheese Model & other Accident Causation Frameworks|url=http://goflightmedicine.com/tenerife-disaster/|access-date=October 13, 2014|publisher=Go Flight Medicine}}</ref><ref>{{Cite journal|title = The Evolution of Crew Resource Management Training in Commercial Aviation|author1 = Helmreich, R. L.|author2 = Merritt, A. C.|author3 = Wilhelm, J. A.|journal = [[Int. J. Aviat. Psychol.]]|year = 1999|volume = 9|issue = 1|pages = 19–32|doi = 10.1207/s15327108ijap0901_2|pmid = 11541445|url = http://homepage.psy.utexas.edu/homepage/group/helmreichlab/publications/pubfiles/Pub235.pdf |archive-date=March 6, 2013 |archive-url=https://web.archive.org/web/20130306162247/http://homepage.psy.utexas.edu/homepage/group/HelmreichLAB/publications/pubfiles/Pub235.pdf |citeseerx = 10.1.1.526.8574}}</ref> In 1978, a second airport was opened on the island of Tenerife, the new [[Tenerife South Airport]] (TFS), which now serves the majority of international tourist flights. Los Rodeos, renamed Tenerife North Airport (TFN), was then used only for domestic and inter-island flights until 2002, when a new terminal was opened and Tenerife North began to carry international traffic again. The Spanish government installed a ground radar system at Tenerife North Airport following the accident.<ref name=TIC /><ref>{{Cite web|url=http://www.tenerife-training.net/Tenerife-News-Cycling-Blog/tenerife-north-airport-will-get-a-new-control-tower-more-than-30-years-after-worlds-biggest-air-disaster/|title=Tenerife North airport will get a new control tower, more than 30 years after world's biggest air disaster|website=www.tenerife-training.net|access-date=March 4, 2017}}</ref> == Memorials == {{multiple image |header=Tenerife disaster memorials |total_width=600 |image1=International Tenerife Memorial March 27, 1977.jpg |caption1=Memorial on Tenerife |image2=Westgaarde.jpg |caption2=Westgaarde Cemetery |image3=TenerifeMemorial.JPG |caption3=Westminster Memorial Park }} 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]], US. In 1977, a cross in [[Rancho Bernardo, San Diego|Rancho Bernardo]] was dedicated to nineteen area residents who died in the disaster.<ref>{{cite news |author=kacejataste |agency=Pomerado News|date=January 29, 2009 |title=Around the Ranch: All about Battle Mountain |url=http://www.sandiegouniontribune.com/pomerado-news/sdpn-around-the-ranch-all-about-battle-mountain-2009jan29-story.html |newspaper=[[The San Diego Union-Tribune]] |access-date=May 5, 2018 }}</ref><ref>{{cite news |last=Himchak |first=Elizabeth Marie |date=June 9, 2016 |title=Rancho Bernardo cross undergoes repairs |url=http://www.sandiegouniontribune.com/pomerado-news/news/local-news/rancho-bernardo/sdpn-rancho-bernardo-cross-undergoes-repairs-2016jun09-story.html |newspaper=[[The San Diego Union-Tribune]] |access-date=May 5, 2018 }}</ref> In 2007, 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 (1942-2006).<ref>{{cite news |date=February 19, 2007 |title=COMUNICADO: Monumento International Tenerife Memorial donado al Cabildo; avanzan los trabajos de cimentación en la Mesa Mota |language=es |trans-title=STATEMENT: International Tenerife Memorial Monument donated to the Cabildo; Foundation work progresses at Mesa Mota |newspaper=[[El Economista (Spain)|El Economista]] |url=http://www.eleconomista.es/mercados-cotizaciones/noticias/166139/02/07/COMUNICADO-Monumento-International-Tenerife-Memorial-donado-al-Cabildo-avanzan-los-trabajos-de-cimentacion-en-la-Mesa-Mota.html |access-date=March 21, 2012}}</ref><ref>{{cite news|url=https://www.tenerife-memorial.org/es/|title=Monumento Conmemorativo Internacional March 2, 2007 + Foto-Video|language=ES}}</ref> == Documentaries == The disaster has been featured in many TV shows and documentaries. These include * Episode 1 of ''[[Survival in the Sky]]'', "Blaming the Pilot" (1996) * Episode 12 of ''[[Seconds From Disaster]]'', "Collision on the Runway" (2004) * Episode 625 of PBS's ''[[Nova (American TV series)|NOVA]]'', "The Deadliest Plane Crash" (2006) * The PBS special ''Surviving Disaster: How the Brain Works Under Extreme Duress'' (2011), which was based on [[Amanda Ripley]]'s book ''The Unthinkable: Who Survives When Disaster Strikes - and Why'' * An episode of ''[[Destroyed in Seconds]]'' * Episode 133 (S16E03) of the Canadian TV series ''[[Mayday (Canadian TV series)|Mayday]]'' (known by different names in different countries), "Disaster at Tenerife" (2016), as well as the earlier in-depth 90-minute special "Crash of the Century" (2005). * Footage of the wreckages was included in the 1979 film ''Days of Fury'', narrated by [[Vincent Price]]. * Episode 5 of the [[Nebula (streaming service)|Nebula]] series "Under Exposure" (2023) by Neo. == See also == * [[List of accidents and incidents involving commercial aircraft]] == References == {{Reflist|2}} * ''Collision on Tenerife: The How and Why of the World's Worst Aviation Disaster'' by Jon Ziomek (Post Hill Press, 2018). == External links == {{Commons category}} {{external media | float = right | width = | image1 = [http://www.airliners.net/search/photo.search?regsearch=PH-BUF&distinct_entry=true PH-BUF (KLM 4805)] – Airliners.net | image2 = [http://www.airliners.net/search/photo.search?regsearch=N736PA&distinct_entry=true N736PA (Pan Am 1736)] – Airliners.net | video1= [https://www.youtube.com/watch?v=bJkLrLwmV0Y Survivor remembers deadliest aviation disaster in Tenerife] – [[CBS This Morning]] – March 27, 2017 }} <!--===========================({{NoMoreLinks}})===============================--> <!--| DO NOT ADD MORE LINKS TO THIS ARTICLE. WIKIPEDIA IS NOT A COLLECTION OF |--> <!--| LINKS. If you think that your link might be useful, do not add it here, |--> <!--| but put it on this article's discussion page first or submit your link |--> <!--| to the appropriate category at the Open Directory Project (www.dmoz.org)|--> <!--| and link back to that category using the {{dmoz}} template. |--> <!--| |--> <!--| Links that have not been verified WILL BE DELETED. |--> <!--| See [[Wikipedia:External links]] and [[Wikipedia:Spam]] for details |--> <!--===========================({{NoMoreLinks}})===============================--> *[http://www.project-tenerife.com/engels/rapporten.htm Official Spanish and Dutch accident reports] ** [https://www.faasafety.gov/files/gslac/courses/content/232/1081/finaldutchreport.pdf English translation of Spanish report and Dutch response] ** "[http://www.fomento.gob.es/MFOM/LANG_CASTELLANO/ORGANOS_COLEGIADOS/CIAIAC/PUBLICACIONES/HISTORICOS/A-102-103-1977/ A-102/1977 y A-103/1977 Accidente Ocurrido el 27 de Marzo de 1977 a las Aeronaves Boeing 747, Matrícula PH-BUF de K.L.M. y Aeronave Boeing 747, matrícula N736PA de PANAM en el Aeropuerto de los Rodeos, Tenerife (Islas Canarias)]." – Hosted by the [[Civil Aviation Accident and Incident Investigation Commission]] {{in lang|es}} *[http://www.project-tenerife.com/engels/PDF/alpa.pdf Human Factors Report on the Tenerife Accident] – [[Air Line Pilots Association, International|Air Line Pilots Association]] of the United States ([https://web.archive.org/web/20110715122130/http://www.project-tenerife.com/engels/PDF/alpa.pdf Archive]) *[http://www.project-tenerife.com/engels/index.htm Project Tenerife]&nbsp;– website about the Tenerife disaster *[[iarchive:days-of-fury-1979|Watch ''Days of Fury'' at the Internet Archive]] {{Pan Am}} {{KLM Royal Dutch Airlines}} {{Aviation accidents and incidents in Spain}} {{Aviation accidents and incidents in 1977}} {{Portal bar|Spain|Netherlands|United States|Aviation}} [[Category:Accidents and incidents involving the Boeing 747]] [[Category:Airliner accidents and incidents involving ground collisions]] [[Category:Airliner accidents and incidents caused by pilot error]] [[Category:Airliner accidents and incidents involving fog]] [[Category:Aviation accidents and incidents in 1977]] [[Category:Aviation accidents and incidents in Spain]] [[Category:KLM accidents and incidents]] [[Category:Pan Am accidents and incidents]] [[Category:Tenerife|Disaster]] [[Category:1977 in the Netherlands]] [[Category:1977 in Spain]] [[Category:Netherlands–Spain relations]] [[Category:Netherlands–United States relations]] [[Category:Spain–United States relations]] [[Category:March 1977 events in Europe]] [[Category:History of the Canary Islands]] [[Category:Airliner accidents and incidents caused by tailstrikes]]'