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View Full Version : The Tenerife 747 Collision--what if?



Tamara
28 Feb 14,, 08:13
Remember, back in 70's, a KLM 747 hit a Pan Am 747 on the ground?

One of the criticisms against the KLM Captain was when he saw the collision situation, he didn't abort the take off but rather, tried to take off over the Pan Am.

Well, what if he had tried to abort. Brakes, full thrust reversal. Assuming that there wasn't a collision, what would that be like inside the cabin?

Has there ever been an aborted take off like that, say at 140 knots, so we might know what it would be like?

lemontree
28 Feb 14,, 09:29
A takeoff is aborted only if the aircraft's speed is below the takeoff decision speed known as V1.
If the aircraft speed is above V1 then takeoff is not aborted.

The V1 for a 747 is 145 knots, which is very close to 140 knots, hence an aborted take off for a 747 at 140 knots would be very dangerous or fatal.

Aero 11 - Rejected Takeoff Studies (http://www.boeing.com/commercial/aeromagazine/aero_11/takeoff_story.html)

Boeing studies indicate that approximately 75 percent of RTOs are initiated at speeds less than 80 kt and rarely result in an accident. About 2 percent occur at speeds in excess of 120 kt. The overruns and incidents that occur invariably stem from these high-speed events.

Tamara
28 Feb 14,, 09:36
Well, two things.

First of all, that's not the question. I'm wondering if there are any accounts of what happens in the cabin for an take off abort at that speed.

Secondly, while it is all what if, one thing we do know is that in the decision not to abort the KLM take off and trying to fly out of the situation, no one got out alive from that aircraft.

lemontree
28 Feb 14,, 09:51
Well, two things.

First of all, that's not the question.


Has there ever been an aborted take off like that, say at 140 knots,...

I answered the above query put by you.

sated buddha
28 Feb 14,, 09:57
I'm wondering as for bikers, does "target fixation" work on pilots too? i.e. you (and your bike/plane) invariably (and involuntarily) go where you look.

Tamara
28 Feb 14,, 10:16
I answered the above query put by you.

My apologies, I misread what you were trying to say.

As far as the report goes, it's only as accurate as when it was produced.

Doing some research here.........D-ABZA, a Lufthansa cargo 747 took a bird strike on 20 March 1993 and had to abort above V1 ( See (http://www.int-birdstrike.org/Vienna_Papers/IBSC22%20WP26.pdf)). Details of the report are minor about the aircraft (overran runway, into the dirt to avoid Frankfurt Airport's ILS) and since it was a cargo jet, odds are there was no one in the cabin to feel it.

Found out about D-ABZA from this report (https://www.iata.org/iata/RERR-toolkit/assets/Content/Contributing%20Reports/NLR_Rejected_takeoff_after_V1.pdf).

lemontree
28 Feb 14,, 10:24
Tamara,

Check out the video on this webpage. This does not answer your specific question on the effect inside the cabin, but it shows the effect on the wheels and brakes on the aircraft, and also shows that an abort takeoff at 140 knots just might be possible.
This Is What Happens When a One-Million-Pound Boeing 747 Aborts Take Off (http://gizmodo.com/5803096/this-is-what-happens-when-a-one+million+pound-boeing-747-aborts-a-take-off)

sated buddha
28 Feb 14,, 10:44
This Is What Happens When a One-Million-Pound Boeing 747 Aborts Take Off (http://gizmodo.com/5803096/this-is-what-happens-when-a-one+million+pound-boeing-747-aborts-a-take-off)

For the Captain (not you, but the one flying that monster and slamming on the brakes at 320 kmph ......)

35728

omon
28 Feb 14,, 17:13
all your "feelings" inside would be similar to as if you were in a car, actually you may get more G in a car, since it deselerates fatser than plane. but noise and smell of buring brakepads, and shaking and vibration will make such experience unforgetable. oh and you might spill your drink.

Stitch
28 Feb 14,, 17:31
Chogy would probably be a good person to ask about this, I'm pretty sure he's got some experience in flying the 747's "little brother".

Firestorm
28 Feb 14,, 20:21
Remember, back in 70's, a KLM 747 hit a Pan Am 747 on the ground?

One of the criticisms against the KLM Captain was when he saw the collision situation, he didn't abort the take off but rather, tried to take off over the Pan Am.

Well, what if he had tried to abort. Brakes, full thrust reversal. Assuming that there wasn't a collision, what would that be like inside the cabin?

Has there ever been an aborted take off like that, say at 140 knots, so we might know what it would be like?
Two things:

1. There was very heavy fog on the runway. The KLM captain didn't see the Pan Am jet till it was too late.

2. There was a chance that the KLM 747 could have actually been able to go over the Pan Am 747 if the Captain hadn't taken on extra fuel at Tenerife prior to takeoff. The added weight caused the takeoff roll to be longer than it might have been. Without that the aircraft might have just been able to avoid the Pan Am 747.

The biggest mistake made by the KLM captain of course was trying to take off before being given the final go-ahead by the controller.