26th August 2006
KLM Pan Am Disaster
Source: PIA CRM Islamabad
KLM - Pan Am
March 27, 1977
Tenerife is in Spanish jurisdiction, therefore, the NTSB was unable to issue a report even though it involved a United States airline. The Airline Pilots Association decided to tackle the accident and issue a U.S. style report with the collaboration of human factors specialists. An extensive document was produced which examined in great detail the human performance aspects of the tragedy. A condensed version of the tragic events is presented in John Nance's book, Blind Trust:
... And then came the granddaddy of them all - an accident so horrendous in terms of totally avoidable loss of life that it galvanized the civilized world. Even the crash of a Japan Airlines cargo DC-8 in Anchorage, Alaska, on January 13, 1977, which was caused by a drunken American contract captain losing control ot his aircraft, was invisible to the public compared with the events of March 27, 1977.
In short, a very senior and very experienced Boeing 747 captain under substantial stress decided that what he had heard from the control tower was what he had been expecting - takeoff clearance.
Seconds later, Captain Jacob Louis Veldhuyzen van Zanten, fifty years of age, a senior pilot with eleven thousand hours of flight time, and head of the KLM Training Department, saw a sight ahead of him on the runway at Tenerife in the Canary Islands that exceeded his wildest nightmares. As KLM 4805 passed 15 knots of airspeed
and began emerging from a fogband that had rolled across the runway, another Boeing 747, Pan Am Clipper 1736, sat right in front of it.
Captain van Zanten had no choice. He could not stop. He couldn't swerve at that speed. His only chance was to leap over the Pan Am Clipper. The KLM captain yanked the control column as far back as it would go, the KLM 747 reared up in the air, the tail striking the runway and embedding metal in sixty feet of concrete and finally became airborne. For a second or two as its nose gear and front section passed safely over the Pan Am Clipper, it seemed that they might make it. But the rotation had been too late - too slow. They were too low.
The main landing gear of the KLM 4805 smashed into the other jumbo destroying the top of the Pan Am fuselage and ripping away KLM's main gear.
Mortally wounded, robbed of airspeed by the energy transferred to the impact with Pan Am, KLM settled back to the runway at less than 100 knots, skidded, and burst into intense flames. Not one human being escaped from the inferno, which consumed 234 passengers and 14 crew members.
On the destroyed and collapsing Pan Am Clipper, some were escaping the twisting, burning airframe as the intense flames and smoke enveloped it. But in the end, 335 would be burned to death - the passengers all vacationers on a charter trip.
The disasterously mistaken assumption of Captain van Zanten that the runway was clear and they were cleared to take off, was the saddest - and most dramatic - example of information transfer failure in commercial aviation history. That one decision killed 583 human beings and maimed many more. It was the accident the entire industry had dreaded - the collision of two jumbo jets. No one, however had predicted that such would happen on the ground.
The two 747's diverted into Tenerife for fuel because of a terrorist bombing that had shut down Las Palmas airport in the Canary Islands, which had been their destination. The controller's native language was Spanish. The Pan Am Clipper crew's native language was English, and the .KLM crew's native language was Dutch. All three, however, in their radio communications, were speaking the international language of aviation: English. Unfortunately, accents and phraseology in different parts of the world make such
communications in a common language difficult at times. It is very, very easy to misunderstand - which is exactly what happened at Tenerife.
Captain van Zanten also had a crew-duty time problem. If his crew did not get back to Amsterdam before the end of their maximum authorized crew-duty day, a serious violation for the Dutch would occur; and shutting the flight down somewhere else with a charter group would mean incredible expense and confusion involving housing and feeding of the passengers. The unexpected diversion had put them in a bind. The captain was very anxious to get out of Tenerife and on his way to Las Palmas, where another charter group awaited pickup.
Yet, they had to refuel and wrestle with a minor hydraulic problem at Tenerife first, and during that time (due to congested parking) their huge 747 had blocked the Pan Am Clipper from leaving. With all those frustrations, Captain van Zanten was upset.
The runway at Tenerife was being obscured by clouds, which were periodically moving across the runway, providing a localized fog condition. KLM taxied out first, reaching the end of the runway as Pan Am was taxiing down the runway behind it. Since the taxiways near the terminal were too narrow for 747's, the jumbos had to use the runway until about midfield, then taxi off onto a parralle taxiway, and use that to the end of the runway. The Pan Am Clipper
had missed its first turn and was trying to find the second one when Captain van Zanten's right hand began nudging the four KLM 747 throttles forward.
His co-pilot, thirty-two year old Klass Meurs, was instantly alarmed.
" Wait a minute, we do not have a [Air Traffic Control] clearance "
The captain brought the throttles back to idle. It was irritating for one of KLM's most senior captains to have to be reminded by his co-pilot of something so very basic.
" No, I know that; go ahead [and] ask "
Meurs picked up his microphone.
" Eh, the KLM 4805 is now ready for takeoff
and, eh, we are waiting for our ATC clearance "
The heavily accented voice of the Tenerife tower controller came back, reading the clearance in English, and Meurs repeated it after the captain had nodded and said, "Yes".
As Meurs was finishing his read-back of the clearance, the captain's hand once again began nudging the throttles forward.
" We go - check thrust "
Meurs was startled. His finger was still holding down the microphone button, he could see what the captain was doing, and he was confused. That was an ATC clearance, not a takeoff clearance. But this man was his boss. He had already corrected him once. Maybe the captain had heard something in that clearance that he, Meurs, had missed.
Without letting go of the transmit button on his microphone, Meurs stated the obvious - in the hope it was already approved.
" We are now - eh - taking off "
The sound of the 747's huge, high-bypass engines winding up filled the cockpit as Meurs waited for word from the tower.
Finally, the tower controller keyed his microphone, and Meurs heard him speak the word "Okay...." before a loud squeal blocked the rest of the transmission.
In the Pan Am cockpit, and in the tower, Meurs' words had been heard as "We are now at takeoff." Mentally, the Pan Am pilots assumed the word "position" should have followed. Certainly, he was reporting in takeoff position. The phrase "at takeoff" was bad English, but "at takeoff position" would make sense.
Nevertheless, Pan Am co-pilot Bob Bragg keyed his microphone to make sure they knew Pan Am was still on the runway.
" And ... we're still taxiing down the runway, the Clipper 1736 "
At that very same instant, the tower controller was telling KLM:
" Okay, stand by for takeoff - I will call you ..."
On the flight deck of KLM, the two messages cancelled each other out in a loud squeal. All the KLM crew heard was the word "Okay..." followed by the squeal, and the words "...Clipper 1736."
The tower controller answered the Pan Am Clipper.
" Papa Alpha 1736, report runway clear "
" Okay. We'll report when [we are] clear "
" Thank you "
First Officer Meurs was concentrating on the takeoff. The "Okay" from the tower had come over the KLM crew's radio with clarity, and with that it was reasonable to conclude that they were cleared to take off. Besides, the captain acted sure of that fact.
But the Second-Officer / Flight Engineer, Willem Schreuder, seemed concerned. The KLM was gaining speed and entering another of the clouds that had been blowing across the runway. He could see nothing ahead. What did Pan Am mean: "We'll report when, [we are] clear?". They were already clear - weren't they? How could Captain van Zanten have started the takeoff if not?
"Is he not clear then?" Schreuder asked.
The captain asked in a clipped manner, "What did you say?"
"Is he not clear that Pan American?"
The KLM 747 was now at 80 knots and accelerating.
Both the captain and First Officer Meurs responded to Schreuders tentative inquiry.
Schreuder shut up. The captain must be right.
Twelve seconds later, the Pan Am Clipper loomed up in the
The last recorded words from the crew of KLM was a familiar epithet to those who regularly hear cockpit voice recorder tapes. More than one pilot had uttered the same phrase when confronted with the possibly irreversible reality of impending disaster.
Captain van Zanten said simply: "Oh, shit!"
The tragedy at Tenerife held many lessons for commercial pilots and managers alike. Indeed, Captain van Zanten was a manager - the head of KLM's Training Department ... (his picture, in fact, had just appeared in worldwide color advertisements for KLM when the crash occurred.) But the fact that he represented an extreme authority figure to his subordinates intimidated them, whether he had tried to achieve that result or not. The accident stands as a singular and irrefutable justification for intense training at all airlines in aircrew assertiveness in the cockpit -- the willingness to make members know, even if they don't want to listen.