Never take off without take off clearance.

Ladies and Gentlemen,

The world's worst air disaster occurred in Los Rodeos Airport, Tenerife, Canary Islands in the Atlantic when a KLM Jumbo bound for Amsterdam crashed on takeoff with a Pan American Jumbo on the runway. 583 people died, all from the KLM jumbo and 335 out of 380 passengers on the Pan Am jumbo.

The lesson to be learned from this is never never take off unless you are sure of take clearance.

On March 27, 1977, Gando Airport in Las Palmas, Canary Islands, the original destination for both these aircraft was temporarily closed due to a bomb hoax. As a result all aircraft including these 2 jumbos were diverted to Los Rodeos Airport in the nearby island of Tenerife, a much smaller airport totally inadequate to handle heavy aircraft traffic or large planes, being much smaller with only one active runway, Runway 12/30.

The take off runway was Runway 12, meaning the runway is facing 120 degrees, Magnetic Compass Heading.

Just before the tragic accident, Pan Am had just landed on Runway 12, while the KLM was waiting for take off clearance on Runway 12 at the hold short line, meaning just outside the active runway, waiting for clearance from the tower to enter it.

After landing on Runway 12, Pan Am is told to taxi till the end of Runway 12, make a U turn on it, then taxi back on the same runway and exit at the 3rd taxiway, so as to clear off from Runway 12, for KLM who was waiting at the threshold of Runway 12 to enter it and take off.

While Pan Am is on Runway 12 and still taxiing, KLM is now asked to taxi into position onto the active Runway 12 and hold (to enter Runway 12 and wait at the take off position for clearance to take off), until Pan Am clears off the runway.

The problem now is fog and the KLM cannot see the Pan Am, and neither can see the other. Moreover Los Rodeos Airport does not have ground radar, and the tower cannot see either plane due to fog and has to rely entirely on radio communication.

At this point, both aircraft are on the ground and facing each other on the same Runway 12, KLM at the threshold of Runway 12 at take off position, and Pan Am taxiing towards the KLM so as to exit the runway at a taxiway exit.

The tower tells Pan Am to clear off Runway 12 at the 3rd taxiway as as taxiway 1 and 2 are blocked by other traffic, and to report it once it has cleared off from Runway 12.

Instead of clearing off the runway at the 3rd exit, mistakenly the Pan Am pilot continues taxiing on the live runway, getting closer towards the KLM at the other end of the runway, and starts to exits only on the 4th taxiway. This means the Pan Am now has come much closer to the KLM who is waiting at the threshold at Runway 12.

There are these 2 additional factors that contributed to the crash and without them, perhaps there may not have been this crash.

One, if Pan Am had exited on the 3rd taxiway exit as advised, there would have been more runway length for the KLM to have climbed over the Pan Am.

Second, the KLM decided to take on a full compliment of fuel at Los Rodeos, sufficient to fly it all the way back to Amsterdam.

Since Gando airport was only a half hour flight from Los Rodeos, had the KLM taken on just enough fuel to take it Gando, it would have been much lighter and perhaps would have been able to clear the Pan Am. With all that fuel, the aircraft was much heavier thereby needing a longer take off roll for lift off, which contributed to the accident.

At this point the KLM is given flight direction as follows: 1705:53.4 - 1706:08.9
TENERIFE TOWER eight seven * zero five uh you are cleared to the Papa Beacon climb to and maintain flight level nine zero right turn after take-off proceed with heading zero four zero until intercepting the three two five radial from Las Palmas VOR.

This is not take off clearance for KLM. It is merely clearance for the route the aircraft to take after it is airborne. For take off, the tower has to specifically give that clearance.

Due to a crossing of radio communication between the tower, the Pan Am and the KLM at this point, the KLM never specifically received the clearance but only heard "OK" when the entire sentence from the tower to the KLM was "OK, Wait for my clearance, I will call you".

The tower of course was waiting at this point to hear from the Pan Am that it has cleared off from Runway 12, at which point it will give clearance to the KLM to take off.

Mistakely assuming it had take off clearance the KLM, having heard the "OK", starts the ground roll with full thrust and begins to accelerate. At this point neither aircraft see each other due to fog. In fact both aircraft are on the ground facing each other with the KLM fast approaching the Pan Am.

Pan American is taxiing, still partially on the Runway 12, with only it's nose section having entered the taxiway exit No. 4, while it's fuselage and tail section is still blocking the main runway.

After having increased speed the first officer of the KLM reads out V1 meaning it has reached a speed at which point it can no longer abort the take off. It has to continue the roll and take off at V2 speed.

At this point, for the first time, the Pan Am cockpit through the fog, sees the lights of the KLM heading straight at them on Runway 12.

The KLM captain realises he is going to collide with the Pan Am on the ground, and too late to abort the take off, desperately pulls back hard back on his yoke, trying to lift his nose and climb out.

Unfortunately at that point the KLM, carrying a full load of fuel and very heavy, needed a much longer ground roll to take off. The KLM's nose did manage to lift but it's tail still on the ground, smashes against the tail of the Pan American still on the runway.

I guess the moral of the story is never never take off unless you are absolutely sure.

I have pasted the radio communication of the aircraft and tower just before the disaster, below.

1705:22.0
PAN AM CAPTAIN That's two. [Captain Grubbs is identifying the second turn-off from the runway as the Pan Am continues to back-taxi]

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 Nee, dat weet ik, vraag maar. [No, I know that, ask for it.]

1705:44.8
KLM (RADIO) Uh, the KLM ... four eight zero five is now ready for take-off ... uh and we're waiting for our ATC clearance.

1705:53.4 - 1706:08.9
TENERIFE TOWER eight seven * zero five uh you are cleared to the Papa Beacon climb to and maintain flight level nine zero right turn after take-off proceed with heading zero 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're cleared to the Papa Beacon flight level nine zero, right turn out zero four zero until intercepting the three two five and we're now (at take-off / uh..taking off).

1706:11.1
[KLM brakes released.]

1706:12.2
KLM CAPTAIN We gaan ... check thrust. [We're going ... check thrust].

1706:14.0
[Engine acceleration audible in KLM cockpit]

1706:18.19
TENERIFE TOWER OK.

1706:19.3
PAN AM (RADIO) No .. eh.[This message was not heard by the KLM crew due to a radio heterodyne.]

1706:20.08
TENERIFE TOWER Stand by for take-off, I will call you. [This message was not heard by the KLM crew due to a radio heterodyne.]

1706:20.3
PAN AM (RADIO) And we're still taxiing down the runway, the clipper one seven three six. [This message was not heard by the KLM crew due to a radio heterodyne.]

1706:19.39 - 1706:23.19
TENERIFE TOWER Roger alpha one seven three six report when runway clear.

1706:29.6
PAN AM (RADIO) OK, we'll report when we're clear.

1706:31.7
TENERIFE TOWER Thank you

1706:xx.x
PAN AM CAPTAIN Let's get the hell out of here.

1706:xx.x
PAN AM FIRST OFFICER Yeah, he's anxious, isn't he.

1706:xx.x
PAN AM FLT ENGR Yeah, after he held us for half an hour. Now he's in a rush.

1706:32.43
KLM FLT ENGR Is hij er niet af dan? [Is he not clear then?]

1706:34.1
KLM CAPTAIN Wat zeg je? [What do you say?]

1706:34.15
KLM UNKNOWN Yup.

1706:34.7
KLM FLT ENGR Is hij er niet af, die Pan American? [Is he not clear, that Pan American?]

1706:35.7
KLM CAPTAIN Jawel. [Oh yes. - emphatic]

1706:40.0
[Pan Am captain sees landing lights of KLM Boeing at approx. 700 m]
PAN AM CAPTAIN There he is ... look at him. Goddamn that son of a bitch is coming!

PAN AM FIRST OFFICER Get off! Get off! Get off!

1706:43.4
KLM FIRST OFFICER Vee-one.

1706:44.0
[PH-BUF (KLM 4805) started rotation.]

1706:47.4
KLM CAPTAIN [Exclamation/expletive]

1706:50
N736PA (Pan Am 1736) records sound of collision. In telecommunications, to heterodyne is to generate new frequencies by mixing two or more signals in a nonlinear device such as a vacuum tube, transistor, or diode mixer. ... In telecommunications, to heterodyne is to generate new frequencies by mixing two or more signals in a nonlinear device such as a vacuum tube, transistor, or diode mixer. ... In telecommunications, to heterodyne is to generate new frequencies by mixing two or more signals in a nonlinear device such as a vacuum tube, transistor, or diode mixer. ...

Gopalan Nair
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Email: nair.gopalan@yahoo.com
Blog: http://singaporedissident.blogspot.com/

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