Worst Aviation Disaster in History, March 27, 1977 KLM/Pan-Am Boeing 747's Collide at Tenerife killing 583
March 27, 1977 KLM/Pan-Am Boeing 747 collision at Tenerife killing 583

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On March 27, 1977, a pair of fully-loaded Boeing 747's, Pan-Am and KLM, collided on the runway at Tenerife. 583 died, the worst commercial aviation disaster in history.

"The magnitude of the accident speaks for itself, but what makes it particularly unforgettable is the startling set of ironies and coincidences that preceded it. Indeed, most airplane crashes result not from a single error or failure, but from a chain of improbable errors and failures, together with a stroke or two of really bad luck. Never was this illustrated more calamitously - almost to the point of absurdity - than on that Sunday afternoon almost forty years ago.[italics added]

"KLM, for its part, is the oldest continuously operating airline in the world, founded in 1919 and highly regarded for its safety and punctuality.

"... a heavy blanket of fog swoops down from the hills and envelopes the airport.

"Because of the tarmac congestion, the normal route to runway 30 is blocked. Departing planes will need to taxi down on the runway itself. Reaching the end, they'll make a 180-degree turn before taking off in the opposite direction. This procedure, rare at commercial airports, is called a 'back-taxi.' At Tenerife in '77, it will put two 747s on the same runway at the same time, invisible not only to each other, but also to the control tower. The airport has no ground tracking radar.

"Unable to differentiate the taxiways in the low visibility, the Pan Am pilots miss their assigned turnoff. Continuing to the next one is no big problem, but now they're on the runway for several additional seconds.

"Because the route clearance comes where and when it does, it is mistaken for a takeoff clearance as well. First officer Meurs, sitting to Van Zanten's right, acknowledges the altitudes, headings, and fixes, then finishes off with an unusual, somewhat hesitant phrase, backdropped by the sound of accelerating engines. 'We are now, uh, at takeoff.'"

The writer is underestimating this point. When the NTSB (American), Dutch, and Spanish investigating teams heard the flight recorder "We are now on [or at] takeoff" the fact is none of them knew what the phrase was referring to.

"The investigation into the accident was conducted by a team consisting of members from Spain, the Netherlands and the United States. They determined that the main cause was the KLM captain taking off without clearance from ATC. They found that due to miscommunication, the pilot thought he did have authorization. KLM took responsibility for the accident and the payment of compensation to the victims or their families."(1)
"Van Zanten releases the brakes. 'We gaan,' he is heard saying on the cockpit voice recorder. 'Let's go.' And with that, his mammoth machine begins barreling down the fog--shrouded runway, completely without permission."

The co-pilot reportedly to grabbed the throttles, pulling them back, telling Van Zanten they hadn't received takeoff clearance from the control towar yet. Van Zanten, pressured for time as his crew was too close to the maximum allowable airtime without a break, argued with the co-pilot as he pushed the throttles forward.

"'At takeoff' is not standard phraseology among pilots. But it's explicit enough to grab the attention of the Pan Am crew and the control tower. It's hard for either party to believe KLM is actually moving, but both reach for their microphones to make sure.

"'And we're still taxiing down the runway,' relays Bob Bragg, the Pan Am first officer.

"At the same instant, the tower radios a message to KLM. 'Okay,' says the controller. 'Stand by for takeoff. I will call you.'

"There is no reply. This silence is taken as a tacit, if not exactly proper, acknowledgment.

"Either of these transmissions would be, should be, enough to stop Van Zanten cold in his tracks. He still has time to discontinue the roll. The problem is, because they occur simultaneously, they overlap.

"If two or more microphones are clicked at the same instant, the transmissions cancel each other out, delivering a noisy occlusion of static or a high--pitched squeal called a heterodyne. Rarely are heterodynes dangerous. But at Tenerife this is the last straw.

"In the Pan Am cockpit, nose--to--nose with the still unseen, rapidly approaching interloper, there's a growing sense that something isn't right. 'Let's get the f[...] out of here,' Captain Victor Grubbs says nervously.

"A few moments later, the lights of the KLM 747 emerge out of the grayness, dead ahead, 2,000 feet away and closing fast.

"There he is!" cries Grubbs, shoving the thrust levers to full power. 'Look at him! Goddamn, that son of a bitch is coming!' He yanks the plane's steering tiller, turning left as hard as he can, toward the grass at the edge of the runway.

The speed of the KLM was over 270 km/h.

'Get off! Get off! Get off!" shouts Bob Bragg.

"Van Zanten sees them, but it's too late. Attempting to leapfrog, he pulls back on the elevators, dragging his tail along the pavement for 70 feet in a hail of sparks. He almost makes it, but just as his plane breaks ground, its undercarriage and engines slice into the ceiling of the Victor, instantly demolishing its midsection and setting off a series of explosions."



Bob Bragg, the Pan Am first officer, survived:

"Bragg describes the initial impact as little more than 'a bump and some shaking.' All five men in the cockpit, located at the forward end of the 747's distinctive upper--deck hump, saw the KLM jet coming and had ducked. Knowing they'd been hit, Bragg instinctively reached upward in an effort to pull the 'fire handles'- a set of four overhead-mounted levers that cut off the supply of fuel, air, electricity, and hydraulics running to and from the engines. His arm groped helplessly. When he looked up, the roof was gone.

"Turning around, he realized that the entire upper deck had been sheared off at a point just aft of his chair. He could see all the way aft to the tail, 200 feet behind him. The fuselage was shattered and burning. He and Captain Grubbs were alone in their seats, on a small, fully exposed perch 35 feet above the ground. Everything around them had been lifted away like a hat. The second officer and jumpseat stations, their occupants still strapped in, were hanging upside-down through what seconds earlier was the ceiling of the first class cabin."



Incidentally:

"The KLM captain, Jacob Van Zanten, whose errant takeoff roll will soon kill nearly six hundred people, including himself, is the airline's top 747 instructor pilot and a KLM celebrity...."

"Later, when KLM executives first get word of the crash, they will attempt to contact Van Zanten in hopes of sending him to Tenerife to aid the investigation team."




Also:
"The tragedy impacted a lot of changes in the airline industry, mostly to do with communication. The industry started to use standardized phraseology so that ATC, pilots and ground crew all understand the same communication. For example, 'take-off' is never uttered by any personnel except ATC when a plane is actually cleared for a take-off.(2)

And this all-important point:

"In addition, rather than positioning more experienced captains as omnipotent overseers that cannot be questioned, less experienced crew members were taught to challenge decisions when they felt something was wrong. Along with the change, Captains were trained to listen to all information available."(3)

"Two aviation tragedies provide noteworthy examples of what can go wrong when flightcrews fail to work together. The deadliest aviation accident in history, the 1977 collision of 2 B-747s on Tenerife, Canary Islands, in part occurred because the co-pilot and engineer failed to challenge the captain's decision to initiate takeoff before confirming that the runway was clear."(4)

Needless to say, during the July 1914 total meltdown, this is precisely what was not happening. In London no one really challenged British Foreign Secretary Edward Grey from June 28th through to the end of July. No one, not the entire House of Commons nor the House of Lords, the Prime Minister HH Asquith, nor the entire British Cabinet.

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Acknowledgements to Patrick Smith (author) Cockpit Confidential, March 27, 2014: How A Tiny Island Runway Became The Site Of The Deadliest Plane Crash Ever
http://www.businessinsider.com/deadliest-plane-crash-in-history-2014-3
(1) Terror In The Sky: The Top 5 Biggest Air Disasters In History: October 12, 2012
https://flyawaysimulation.com/news/4176/
(2) Ibid.
(3) Ibid.
(4) National Transportation Safety Board, Improve Crew Resource Management
https://www.ntsb.gov/safety/mwl/Pages/was2.aspx