Lengthy glider accident analysis report released

******************************************************* ************************* With all due respect to the two well experienced pilots who died in this accident there is still more which can be learned from the very thorough accident report.

{(A classic and all too common stall/spin caused by a skidding turn)}

Other witnesses who were flying gliders in the area stated that the accident glider was in a tight turn, as if climbing in a thermal, when it entered the spiral. In the later portion of the sequence observed by these witnesses, the glider appeared to be recovering from a spin.

A glider pilot who witnessed the in-flight breakup stated that his glider was soaring about 1,000 feet below the accident glider when he observed the accident glider in a high-speed spiral with a 45-degree nose-down attitude.

The accident glider was climbing in a thermal when one witness saw it at 9,000 feet msl. The glider then departed the thermal on an easterly heading for another thermal. When the witness saw the glider again, he stated that it was coming directly towards him at a 45-degree nose-down angle with the wings bowed.

One ground witness reported that the accident glider had a 45-degree nose-down attitude and was in a 'hard over left hand turn.'

{(Followed by an accelerated stall)}

After two full rotations, the rotation stopped, the flight stabilized on a northeasterly heading, and the nose pitched further down to a near-vertical attitude.

{(In the dive the glider increased speed well beyond Vne as the pilot tried to pull out of the dive in a high g pull-up) (They may or may not have used the air brakes to slow down the acceleration)}

The accident glider was observed to level its attitude, with the wings bending upward and the wing tips coning higher. The outboard wing tip panels departed from the glider, the wings disintegrated, and the fuselage dove into the ground.

The witness reported that the glider became stabilized on a westerly heading with the wings bowed up 45 degrees. He then observed the wings collapse.

Another witness caught something out of the corner of his eye moving at a very high rate of speed. He reported that the accident glider spiraled down and completed one 360-degree turn. He stated that he could not tell if the glider was in level flight when the wings failed.

The witness was 180 degrees into a 360-degree turn and heard a Mayday call (later determined to have come from another glider pilot who saw the accident sequence). He did not see the accident occur, but did see fiberglass particles scattering down.

Another witness saw the accident glider climb from 9,000 feet to 11,000 feet msl. He also saw the glider in a spiraling 45-degree nose-down angle. He stated that the nose-down attitude increased to 80 degrees after completing one to two 360-degree turns. ******************************************************* ************************* While I am sure that some of you boomsnappers are waxing outrage at the thought that a flying wing enthusiast would dare use real accidents to make a point; after you get your blood pressure under control you might want to take a hard look at the root cause of this accident and two of the fatal accidents which occurred this past September. Stall/spins caused by skidding turns kill and injure a lot of people fron the well trained and experienced pilots to novice pilots. It is my humble opinion that aircraft design is a major contributing factor and one remedy is well designed 'inherently stable ' wings.

I cannot believe you would stoop as low as this to prove some misguided thought on flying wings. You show me a flying wing with an aspect ratio of 38+ and tell me it wont be subject to tip stalls. I was going to comment on your quotes about Clems death now you quote 2 friends of mine death.

Slingsby you are a F*^king Ahole.

Al

snip to spare the world more crazed delusions.

That is the most extensive accident report I've ever seen and for a glider accident, unprecedented, But then Engen was the former head of the FAA. One thing I didn't see though

There you go again Al, the pot calling the kettle black. Just because you do not agree with someone doe not mean you have to resort to name calling. Clean up your act!

If you dont take offence to idiots using fatal accidents of your friends to prove a innane point about stupid flying wings then I guess you should join his ranks of A'holedom.

Al

With all respect to the fact that you are entitled to have your own opinion, you, sir, are obviously an idiot. Never heard of an Ercoupe did you? Now you're a safety nazi who's answer to airplane crashes is to make aircraft that won't supposedly stall. Already been done, didn't work. Nothing that moves faster than 10 mph or gets you more than 10 feet above the ground is safe. Properly trained pilots are safe. If Bill I. Had never experianced his spoilers popping open by themselfs, Then i can understand the event. Either one of those folks could do spin recoveries with their feet tied behind their backs. Maybe those pilots, who by the way have more time doing mag-checks than you will ever have in the air, were unaware of the propensity for open class gliders to self-deploy the spoilers during major wing bending events. I have done spins and spin recoveries personally with Mr Engan in the death glider itself. The Puchacz. He can fly better with his knees than you likely ever will with both hands. Just to straighten you out, the mass of the tailboom will only contribute to the centrifigual force, and aggravate the groundloop, IF the center of mass is behind the main wheel. Having greater mass ahead of the main is stablizing. You won't ground loop with that training wheel in front stuck to the pavement. Ever flown 2 identical planes with different gear? I have. How about a C-150 VS a C-150 taildragger? Guess which one wants to groundloop, and which one wouldn't do it if you tried? Oh wait! how could that be? thay BOTH have a tailboom? If you would like an education about one sucessfull, in production, flying wing, with an unstable airfoil, and FLAPS, and no tail, look into the Swift. Sure, it's not 40/1 but it flys very well. The engineers are Stanford Professors and have the best resorces available to them. By the way, The only boom snapping I have seen was from putting low performance pilots in high performance aircraft. (Contest outlandings aside, for those unlucky few) Where I fly, a groundloop is an extreamly rare event, even though pilots with low time must land in strong gusty crosswinds on a daily basis. So much foor that selling point. Keep your fantasy to yourself, and if the gliders are that good, soon we will all fly them. If they are not, they'll fizzle out like a bad

Slingsby wrote>>>>>>>>>>>>>.>after you get your blood pressure under

I have seen a lot of Air Force accident reports that read; The pilot allowed the aircraft to assume an attitude from which recovery was not possible. That is what happened to Ivens & Engen.

It is just too simplistic to blame this accident on a skidding turn. Low time pilots will try and make the ship turn to runway heading by shoving in a bunch of left rudder when they are too low to bank. The left rudder makes the left wing go down, so the pilot stops that with right stick. The sagebrush is getting very close, so our low time pilot pulls back on the stick and we have another skidding turn to final with a half turn spin. It is hard for me to believe two highly experienced pilots performed this maneuver while trying to thermal at 10,000 feet.

So what did happen? I don't know and nobody else does either. The day before, 12 June, '99, there was a strong shear working in the accident area. We hit it in our ASH-25 and it rolled us into a 90 degree bank before our corrective action stopped the roll. If slower minds or weaker hands were faced with the same situation, I could very well see the nose dropping and then we are very close to, 'The pilot allowed the aircraft to assume an attitude from which recovery was not possible.'

Unusual Attitude Recovery, that's what you do when the brown stuff is up there where the blue stuff is supposed to be. Roll to the nearest horizon and pull the nose to that horizon. If Engen was flying, that would have been his corrective action. Works in the F-4, not so good in the Nimbus 4, but then we are not talking about the same VNE, are we? JJ Sinclair

You have alot of nerve turning a memorial post for two great men into a promotion for your alledged superiority. You have no respect at all. At least rename the thread to 'More hype about my stable pitch positive flying wing with a tail to hold the nose up that won't ground loop' That way, we'll all know to ignore you.

I can't speak to the physics of it, but we have lost two Nimbus 4's now, to outer wing failure after the spoilers were deployed at high speed. I deployed the spoilers on an LS-3 at 100 knots and thought the tips were going to touch. So, I'm thinking the outer panels take whatever load the ship is experiencing at the time the spoilers are deployed and bend up like there's no tomorrow. JJ Sinclair

Under flight characteristics of the accident report; ' The manufacturer noted that the airbrakes would function like spoilers and have the effect of shifting the aerodynamic loads outboard on the wings.'

I don't remember any pitch change when I deployed the spoilers on the LS-3, but the wings did come way up and the same thing will happen when deploying spoilers on the Nimbus 3. A friend of mine saved a ground loop from happening by pulling full spoilers just before he settled into the sagebrush. The wings came up and didn't catch in the brush.

Spoilers or not, I think they had already *had the snitz*, I would like to know why two experienced pilots allowed the ship to get 45 degrees nose down? JJ Sinclair

Hey JJ, I still say they were just pulling up from the dive, maybe they were pulling 4G or so, and the spoilers deployed by themselves. I have flown at least 3 Nimbi that did it to me whilst running the wave cloud at 18k and 90kts or so. Maybe one of them did pull the handle. We'll never know. I can also tell you that many of the military and acro pilots I have checked out tend to over do the stick forward part of the spin recovery with respect to gliders. Makin sure it's flyin, I suppose. I've spun the 4DM, 3DT, 3, 2, and Tupp's DG500. None of them were a pleasent experiance, particulary if the recovery leaves you pointed straight down. That was an amazing report for a glider.