Conversation of pilots of KLM 4805 and Pan-Am 1736

Cockpit Voice Recorders of both planes determined the cause of the disaster. This is the main evidence for the collision. (see Tenerife Disaster)

CVR Transcripts of KLM 4805 and Pan Am 1736

It is clear that there are misinterpretations of communications among the flight crews especially at the KLM Crew.

At 1702:51, the tower contacted KLM 4805:

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Tower: KLM four eight zero five, how many taxiways did you pass?

KLM: I think we just passed Charlie four now.

Tower: Okay, at the end of the runway, make a one eighty and report ready for ATC clearance.

KLM: Okay, sir.

At 1703:29, the flight crew of Clipper 1736 contacted the tower. No one was talking in the KLM cockpit at this time, and the next exchange was clearly audible in that cockpit:

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Pan Am: Would you confirm that you want the Clipper one seven three six to turn left at the third intersection?

Tower: The third one, sir, one, two, three, third, third one.

Pan Am: Very good, thank you.

Tower: Clipper one seven three six, report leaving the runway.

Pan Am: Clipper one seven three six.

The Pan Am crew's acknowledgment of the tower controller's instruction occurred just after the KLM captain told his crew to continue the checklist.

At 1704:24 the discussion in the Pan Am cockpit indicated that the crew saw Taxiway C-1. At 1704:58, the tower informed both flight crews that the runway centerline lights were out of order. At 1705:22, the Pan Am captain said, "That's two" . The CVR transcript contains no subsequent mention of anyone's seeing or passing Taxiway C-3. When the collision occurred 1½ minutes later, the Pan Am airplane was approaching Taxiway C-4.

At 1705:44, a series of communications began, starting with a transmission from KLM's first officer (the times within the parentheses indicate when the transmission ended):

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1705:44--KLM: The KLM four eight zero five is now ready for takeoff, and we are waiting for our ATC clearance. (1705:51)

1705:53--Tower: KLM four eight zero five, you are cleared to the Papa beacon, climb to and maintain flight level nine zero, right turn after takeoff, proceed with heading zero four zero until intercepting the three two five radial from Las Palmas VOR. (1706:08)

1706:09--KLM: Ah, roger, sir, we are cleared to the Papa beacon, flight level nine zero, right turn zero four zero until intercepting the three two five. We are now or . (1706:17)

The last portion of the first officer's readback was rushed and unclear. The two possible interpretations of the last two words are shown within brackets.

About 6 seconds before the first officer ended his readback, the brakes of KLM 4805 were released.

At 1706:12,

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KLM captain :"Let's go--check thrust,"(Began the takeoff roll.)

The controller's reply to the readback of the ATC clearance:

1706:18--Tower: Okay--(pause of 1.89 seconds) stand by for takeoff. I will call you. (1706:22)

Only the word, "Okay," was clearly heard in the KLM cockpit. The rest of the controller's sentence was blocked by an electronic squeal that was caused by the simultaneous transmission from Pan Am, which started shortly after the controller said, "Okay":

Pan Am: And we're still taxiing down the runway, the Clipper one seven three six. (1706:23)

Just the last few words, "Clipper one seven three six," were clearly audible in the tower and the KLM cockpit. Neither the controller nor the Pan Am crew was aware that the vital parts of their transmissions had overlapped.

At 1706:25, about 25 seconds before impact, the controller acknowledged receipt of the Clipper call sign:

Tower: Papa Alpha one seven three six, report runway clear.

Pan Am: Okay, will report when we're clear.

Tower: Thank you. (1706:32)

Immediately after this exchange, which was audible in the KLM cockpit, the KLM flight engineer raised a question:

1706:32--Flight engineer: Is he not clear, then?("Is hij er niet af dan")

Captain: What do you say?("Wat zeg je?")

Flight engineer: Is he not clear, that Pan American?("Hij er niet af, die Pan American")

Captain: Oh, yes (emphatic). ("Jawel")

At the same time the following comments were made in the Pan Am cockpit:

1706:32--Captain: Let's get the hell out of here.

First officer: Yes, he's anxious, isn't he?

Flight engineer: Yeh, after he held us up for an hour and a half.

Captain: There he is--look at him. Damn that son of a bitch is coming straight ahead of us!

First officer: Get off! Get off! Get off!

1706:48--Sound of approaching KLM engines.

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Three seconds before the collision, the KLM captain uttered an exclamation when he saw the Pan Am aircraft. He forced his airplane off the ground but was unable to lift it completely over the Pan Am B-747, which had turned sharply to the left when its flightcrew saw the other airplane approaching.

Captain: God Damn(he pulled the control wheels)....kom op...kom op...kom op... kom op... kom op... kom op...
Vluchten!!!!(Flee!!!!)

1706:50--Impact.

During the impact the Captain stated something but the CVR Lines were cut off. Captain van Zanten's statement remains a mystery.

There were no ground witnesses to the collision.

Both aircraft were destroyed by impact and fire.

Of the 248 occupants of the KLM aircraft, none survived. Of the 389 occupants of the Pan Am aircraft, 54 survived, including the flight crew.

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