Videos Of Challenger 600 Crash In Aspen Colorado


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I've resisted the temptation to post on this forum for some time. This thread however warrants an exception. Don, of all the people I know, I think you rank among the most humble, yet knowledgeable.

Actually, one might reasonably paraphrase Mizar's more recent posts as follows: "I have my opinion which I have strenuously expressed and I am not about to change that opinion. I stand ready to ration

Mac Davis wrote this: Oh Lord it's hard to be humble when you're perfect in every way. I can't wait to look in the mirror cause I get better loking each day. To know me is to love me I must b

Rudder: was the CRJ in YFC landing with a tailwind? Just curious because although I know which accident you are referring to, I can't remember the wind conditions.

No, it was not. But both accidents were not approach accidents but go-around accidents (it is clear from the video that the Challenger crew was trying to go-around for the second time but stalled after lift off). Obviously, the tailwind was a contributing factor to the Challenger stall but regardless a stalled aircraft will exhibit the same behaviour.

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The YFC RJ had ice on the wings which resulted in a stall at a lower than normal AOA. Something to do with the way the anti-icing system worked.

That was a factor. But YFC was a result of a low energy go-around (go-around was initiated after thrust had been reduced to idle). Because of YFC, a different technique was implemented for conducting a go-around from a low energy state. Rapid pitch change is one action to avoid. From the Aspen video, it certainly looks like the aircraft was pitched up rapidly.

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Was it just me, or did it appear that the airplane was actually 'porpoising' prior to the final impact?

Pretty amazing footage- I'm sure with available technology the NTSB will get incredibly enhanced images from that.

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Was it just me, or did it appear that the airplane was actually 'porpoising' prior to the final impact?

Pretty amazing footage- I'm sure with available technology the NTSB will get incredibly enhanced images from that.

Nope, not just you.... two bounces off the nosewheel, the second one caused the first sparks you saw.... after that it looked as though they ran out of airspeed before spool-up for the go-around.

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Because of YFC, a different technique was implemented for conducting a go-around from a low energy state. Rapid pitch change is one action to avoid. From the Aspen video, it certainly looks like the aircraft was pitched up rapidly.

Good point about the rapid pitch action in a low energy situation. In the YFC, contamination was critical, in Aspen, the higher elevation with a rapid pitch up in possibly a low energy state could be crucial, the final report will be interesting I hope. The specific types here with critical wings could be a factor as well.

I think the low energy thing is overblown. We practice it in the sim. Loss of visual upon ground contact. A go-around is made and quite successfully. But, an uncontaminated wing with slats, not at max landing weight, at sea level. Under more difficult circumstances, I would suspect the margins get tighter. But the idea I have heard that one should never consider going around once the thrust levers are closed for landing is not a good blanket idea in my opinion. But obviously, the longer you wait for thrust the more critical things become such as in a bounce situation. And pushing the nose down during a bounce is bad news. Perhaps obvious but it happens. Most interesting to be reported will be if after that quite large bounce, there was a forward push on the control column.

The bounce and then nose down toward the ground and crash reminds me of the Fedex MD-11 in Tokyo.

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I'm surprised that no one has stated much about the 33kt tailwind. I am sure it was a contributing factor as that is a very high speed tailwind.

The 'bouncing' is called porpoising and it virtually impossible for a pilot to counteract that action with forward and aft control input. Continuous inputs normally aggravate the futile inputs as they are always too far behind the aircraft's movements.

If the main gear can handle the impacts there is only one way out of a porpoise, (which is taught to all pilots in the RCAF), and that is to hold the control column/side stick just slightly aft of neutral and apply full power. I know there are a few cases on record where Mil pilots have flown out of a porpoise with a favourable result except for some pretty serious damage to the landing gear.

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I'm surprised that no one has stated much about the 33kt tailwind. I am sure it was a contributing factor as that is a very high speed tailwind.

The 'bouncing' is called porpoising and it virtually impossible for a pilot to counteract that action with forward and aft control input. Continuous inputs normally aggravate the futile inputs as they are always too far behind the aircraft's movements.

If the main gear can handle the impacts there is only one way out of a porpoise, (which is taught to all pilots in the RCAF), and that is to hold the control column/side stick just slightly aft of neutral and apply full power. I know there are a few cases on record where Mil pilots have flown out of a porpoise with a favourable result except for some pretty serious damage to the landing gear.

Contributing factor!?! Hell ya! Does that need to be acknowledged? Isn't that a bit like saying, "a contributing factor to the Titanic's sinking was that she was at sea."?

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I would keep one thing in mind though. And that is the reality that planes have had accidents due to porpoising with a headwind. It will be interesting to see the NTSB analysis of tailwind effect. I believe 33 knots was what the pilot stated on the first go-around which was an airborne report from him. The surface wind report was lower but still quite high.

As well, possible stick pusher inputs need to be examined.

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Mizar

You referred above to an uncontaminated wing with 'slats'. Slat equipped aircraft don't provide any additional protection against things such as contamination etc.

I don't know what sort of anti-stall equipment the Challengers employ, but if so equipped, your observation regarding the stick-pushers potential role in the crash may be right on the mark.

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Defcon, A Mr. Dan Littman, flight dynamics manager, FlightSafety International would seem to offer a slightly contrary view of leading edge devices and contamination. He says, "The simulation also now reflects that in-flight icing has much less effect on a wing with an extended leading-edge device."

http://flightsafety.org/aerosafety-world-magazine/sept-2012/from-bad-to-worse

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My question to all Challenger pilots out there is this, "What is the maximum tailwind component for landing?" I've rarely seen a high performance aircraft certified to land with an excess of 15 kts, but the Challenger might be different. I was hoping to be able to copy the image of the Aspen LOC DME-E approach that I have from my Jepps (it would provide some insight on the dangers of this airport, regrettably I am a techno-moron). When I think of a Challenger landing on an 8000 ft runway that is 7837 ft above sea level with potentially 30 kts up the tail, it frankly scares the crap out of me. Assuming an approach speed of 135KT, the TAS would be way up there (someone help me out here - guessing 150+ kts + 30 T/W = 180 G/S (which it looked to me they had - they were smoking down the runway). This would have required a sink rate of at least 900 fpm just to maintain the glideslope - good luck with the flare and not floating. I doubt very much they knew how much runway they needed if everything went perfectly, because if I was a betting man (which I'm not), they would have calculated an over-run in the hundreds of feet and possibly decided differently.

This looks like a completely preventable accident, and I know I shouldn't say this but I will anyway, in my opinion they had no business trying to land a high performance aircraft under such conditions.

For info: It is a daytime approach only and only one direction for approach and landing. From the FAF to the MAP it has a 6.59 degree slope; now imagine what rate of decent is required to avoid getting high if they had a tailwind on approach.

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Mizar

You referred above to an uncontaminated wing with 'slats'. Slat equipped aircraft don't provide any additional protection against things such as contamination etc.

Take a look at the number of Challenger and RJ crashes due to wing contamination as well as F28 and F100 along with the old unslatted DC-9 accidents. Then look at how many Airbus and rest of MacDac, Boeing and Lockheed wing contamination accidents there have been. You will fnd a whole bunch of accident for the unslatted types and virtually none(partial contribution to Air Florida). Non-slatted swept wing aircraft are much more vulnerable to wing contamination. I may have flown with frost on a Boeing product(but I wont admit it) but wouldnt dare try something like that on an RJ, baby DC-9, F100 etc.

Assuming there are no stickpusher or other unknown issues that surface here, I wonder if the tailwind will be a red herring of poor pilot decision making and instead, pilot handling of a bounce will be critical in the cause. Will have to wait for the report.

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JL & Mizar

An aerodynamic engineer I'm not, but I was a participant in a major aircraft accident investigation some time back. The large jet transport aircraft involved in the take-off crash was not equipped with leading edge devices. Early in, the investigation became somewhat focused on wing contamination, which was ultimately found to be a major contributory factor. At that time the myth associated with wing contamination and the protection leading edge devices provided was widely held.

Prior to the formal organization of the investigation group, I happened into a discussion that was taking place between approximately fifteen airline Captains on this topic at CALPA HQ. These individuals had loads of experience and commanded a wide range of jet transport aircraft. As it was and to a man, including myself, the belief in the myth prevailed.

A fellow airline pilot with all the appropriate credentials who was also later assigned to the investigation was present at this particular gathering. He listened to the discussion with interest, but when asked for his opinion, because of the significance of the subject, our aerodynamic expert decided to put on an impromptu lecture to correct the deficient beliefs. Suffice it to say; leading edge devices do not offer the protection described in the myth.

I should also add, I later attended a lecture at NASA covering wing design and the effects of contamination. Their thoughts were not any different than our aerodynamic expert's.

No offense intended gentlemen and I'll ask because I was guilty too, but what is it about pilots that allows them to take and hold some pretty dangerous positions on matters of aerodynamics without their being particularly well informed, or educated in the subject matter?

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The porpoising appears so violent in both approaches you'd be inclined to think there was some structural damage prior to the last pitch-over. Could have been pylons, stabilizer, tires, or anything, Possibly a stick-shaker on the last pull-up to add to the confusion, maybe flight plan fuel making three tries a bad idea. Certainly does appear to go nose down very rapidly in a relatively short arc. Will the nose on that type drop that fast in a stall?

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JL & Mizar

An aerodynamic engineer I'm not, but I was a participant in a major aircraft accident investigation some time back. The large jet transport aircraft involved in the take-off crash was not equipped with leading edge devices. Early in, the investigation became somewhat focused on wing contamination, which was ultimately found to be a major contributory factor. At that time the myth associated with wing contamination and the protection leading edge devices provided was widely held.

Prior to the formal organization of the investigation group, I happened into a discussion that was taking place between approximately fifteen airline Captains on this topic at CALPA HQ. These individuals had loads of experience and commanded a wide range of jet transport aircraft. As it was and to a man, including myself, the belief in the myth prevailed.

A fellow airline pilot with all the appropriate credentials who was also later assigned to the investigation was present at this particular gathering. He listened to the discussion with interest, but when asked for his opinion, because of the significance of the subject, our aerodynamic expert decided to put on an impromptu lecture to correct the deficient beliefs. Suffice it to say; leading edge devices do not offer the protection described in the myth.

I should also add, I later attended a lecture at NASA covering wing design and the effects of contamination. Their thoughts were not any different than our aerodynamic expert's.

No offense intended gentlemen and I'll ask because I was guilty too, but what is it about pilots that allows them to take and hold some pretty dangerous positions on matters of aerodynamics without their being particularly well informed, or educated in the subject matter?

Pretty Dangerous positions on matters of aerodynamics you say.

I dont think so. It appears that your supposed aerodynamic expert needs to study a little more. I am surprised that I am more knowledgeable than them when I state that non-slatted swept-wing jets are more sensitive to wing contamination. This is no myth. Perhaps the experts wanted to feed you a certain idea to make sure the message was passed on that wing contamination is bad for takeoff. Probably a good idea.

The statistics speak for themselves though if you look at the crashes..

What accident did you study by the way. The Dryden one.

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I am more knowledgeable than them when I state that non-slatted swept-wing jets are more sensitive to wing contamination. This is no myth. Perhaps the experts wanted to feed you a certain idea to make sure the message was passed on that wing contamination is bad for takeoff.

Thank God for that.

Now I can takeoff without contaminated wings without fear.

I was waiting for definitive permissions.

Now, I have it.

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Thank God for that.

Now I can takeoff without contaminated wings without fear.

I was waiting for definitive permissions.

Now, I have it.

You dont have permission to takeoff with contaminated wings(although Im sure you gave yourself permission up there in the bad old days) but Im not surprised that you misinterpreted what I said. What I said is that what is the truth, some jets are more vulnerable to contamination. They are the non-slatted type. Perhaps you dont believe me.

Of course, contamination could be mud or bugs although I think the regulations may only cover frozen contaminants. I believe there is some sort of requirement for CRJ200s for smoothness of the leading edge as well if someone could confirm.

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