Exactly 30 years ago, to be precise on March 27 1977 at 17:07 GMT, the American and the Dutch collided in the worst imaginable way. A topped off (fuel and passengers) Royal Dutch Airlines Boeing 747 named “Rijn” took off on a mist covered single runway Los Rodeos Airport without proper take off clearance, while a fully occupied PanAm Boeing 747 “Clipper Victor” was still taxiing on the runway. 583 people lost their lives, only 70 survived.

KLM captain Van Zanten was too eager to take off and ignored the flight engineer questioning the clearance. Cockpit Resource Management was non existent. As always, there were many, many circumstances all adding up to this horrible event. The 747′s were diverted to Tenerife because there had been a bomb thread in Las Palmas, the destination. The taxiway was crowded with stranded planes. Van Zanten topped off the 747 because he was eager not to wait in Las Palmas, so he could return to Amsterdam without passing his legal flying time. The Clipper had to wait while the Rijn was loading up, because there was maybe 3 feet of clearance lacking for them to pass the KLM 747 and move out earlier. There was no ground radar. The Clipper could impossibly take the exit it was told to take. Radio traffic wording was not completely standardized back then, and in the final seconds, the PanAm (worriedly reporting it was still on the runway) and the tower transmitted at the same time, so the KLM crew missed that last essential bit of information that could have made them realize their fatal mistake.

KLM-1 We gaan. {We’re going}

APP OK.

RDO No .. eh.

APP Stand by for take-off, I will call you.

RDO And we’re still taxiing down the runway, the clipper one seven three six. (RDO and APP communications caused a shrill noise in KLM cockpit – messages not heard by KLM crew.

APP Roger alpha one seven three six report when runway clear

RDO OK, we’ll report when we’re clear.

APP Thank you

KLM-3 Is hij er niet af dan? {Is he not clear then?}

KLM-1 Wat zeg je? {What do you say?}

KLM-? Yup.

KLM-3 Is hij er niet af, die Pan American? {Is he not clear that Pan American?}

KLM-1 Jawel. {Oh yes. – emphatic}

PanAm captain sees landinglights of KLM Boeing at approx. 700m

PH-BUF started rotation

KLM-1 [Scream]

collision

It was later calculated the Rijn would have made it over the Clipper if it had not refuelled. Adding to the drama is that at the time Van Zanten’s picture was on every leaflet of KLM as the senior, smiling, confident captain. It is rumored that at the moment KLM’s management heard of the crash they decided Van Zanten had to lead the investigation on behalf of the company. Little did they know, the man was already there.

More info in this Wikipedia article.