Mishap at Big Sur 2012

Please tell what happened and how it might have been avoided. Names should be ommitted. This forum should help others learn from mistakes that caused or nearly caused a mishap.
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Steve90266
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Mishap at Big Sur 2012

Post by Steve90266 » Sun Dec 16, 2012 11:55 am

My apologies for posting this late entry. I did not feel it would be appropriate for me to post this until I was officially the Safety Director for the SHGA. For the record, the pilot involved submitted this to me roughly two months ago.

Here is a summary of a flight incident which occurred at Wild Cattle launch, Big Sur, CA on September 30th, 2012.

From the PILOT:
"Here are the facts and my opinions surrounding my structural failure at Big Sur.

Please use the information any way you feel will be helpful to the hang gliding community at large. I look forward to the results of your studies. I hope you will forward a copy of your accident investigation to the USHPA and to the SHGA for the benefit of other pilots.

In my mind, there's no mystery as to why this happened. Simple carelessness was almost certainly the cause, but if anyone concludes otherwise, I'd like to hear the reasoning.

The following is generally true for me and is very true for that day.

1. I often choose to accept a lot of distractions (questions from other pilots, assistance to anyone who needs it.)
2. I often choose to accept a lot of responsibilities in addition to my own flying responsibilities (guidance, instruction, public relations, etc).
3. I don't often fly the same glider twice in a row. I fly many different style gliders, including all 3 models Falcon. Of all Falcon models, this specific failure is only possible on the Falcon 3 model.
4. I'm getting older and perhaps losing some of my mental acuity.
5. I'm a very experienced pilot that is likely guilty of complacency during set up and preflight procedures.

The date was Sunday, September 28th in the early afternoon at the launch Wild Cattle launch site a few miles north of the Plaskett Creek Campground. Conditions had been blowing down in the morning but it had turned around and a couple of pilots had already launched into smooth, mostly un-soarable conditions.

I set up my glider (a Falcon 3 195) while monitoring my other responsibilities of running the trip and the student training. My harness was a knee hanger style with a 22 Free Flight 22 gore PDA reserve and a 1/2 shell helmet. I also put a video camera on the wing for this flight (unusual for me). Although I was not in a particular hurry, and I performed what for me is a normal pre-flight, it is clear that I failed to insert the base tube corner bolt through both the lower downtube bracket and the base tube, completely missing the hole in the base tube. This problem is simple to prevent simply by a quick visual inspection that the base tube is inserted all the way to the edge of the lower downtube bracket, before inserting the bolt. It is also very easy to inspect during the pre-flight, by the same simple observation.

The launch conditions were very gentle w/ light winds of around 3 of 4 mph.

After performing a hang check and hook in check, I proceeded to launch the glider, only to find the wings folding upwards a moment before I became airborne.

At the next moment, the slope of the hill steepened, the ground dropped away and I found myself several feet in the air with each down tube being pulled laterally out of my grip. At this point the glider has a massive amount of dihedral, substantially increasing the sink rate and glide ratio of the glider, and bringing it back down to the slope of the hill. Within 3 or for seconds from the moment of lift off, I settled back to the ground and was sliding smoothly down the slope, very fortunately without a scratch or a bruise.

It has been suggested by some, and I tend to agree, that the glider may have failed sooner, rather than later, due to the fact that I chose not to perform a smoothly accelerating launch run, but rather a jerky, hopping, launch. Had I chose to perform a more conventional launch run, the glider may have remained structurally intact longer, placing me much higher and much further away from the ground at the moment of the structural failure. I would argue that any significant increase of altitude beyond that attained during this accident, would have seriously increased the danger to the pilot (me), and likely require the successful deployment of the reserve system to avoid death or serious injury.

Conclusion:

I believe that the accident was caused solely by my failure to perform a proper, effective pre-flight. The reasons for my failure to perform an adequate preflight may be any one or more of the statements numbered 1 through 5 above.

Please call me if you have any questions.

Respectfully, PILOT"

WITNESS1:
Hi Steve, many of the pilots were around the glider when PILOT launched as he was waiting for it to clear a bit so he sat there awhile. When he moved into position someone was asking about how many steps they should take for the launch run. He started hopping on one foot laughing about how many feet it took. I think he made it about 3 hops, the glider was just getting into the air when the downtube broke away from the base tube
PILOT tried to grab for it but the wings folded very fast and he went down. I think he fell about 8-10 feet, maybe a bit higher because of the slope.
Others were closer to the edge than I who may have had a better view of what happened after the wings folded.
Hope that helps!"

WITNESS2:
I read through PILOT's accident report and I feel like he covered everything. One way that I may have contributed to his glider falling apart sooner was that I gave PILOT a piece of advice just before launch and he humored me by doing the opposite of what I suggested. I advised him to launch very smoothly so his camera mount wouldn't shake or hit the ground. Had he done what I said his control bar may have jiggled apart later in the flight. I was on PILOT's wires before he launched and watched in horror as the wing fell apart. It looked a lot scarier than what PILOT experienced since he only felt to be a few feet from the ground the entire time. To everyone watching from launch it appeared that he was falling vertically nearly 100 feet to the ground. I'm not sure what else to add. It happened so quickly. I hope this helps.

FINDINGS:
The cause of structural failure was an incorrect assembly at the downtube/control bar juncture of the Falcon 3 glider. The control bar was only PARTIALLY inserted into the downtube bracket. Therefore, when the pilot pushed in the keeper bolt, it was not inserted into the control bar, and a false assembly was accomplished. To an untrained or less than critical eye, this false assembly can appear to be correct, and this presents a critical danger to the assembly of the Falcon 3 model glider.

During my investigation into this incident, other pilots revealed that they had made the same mistake in the past. In one instance a pilot stated that he had missed the bracket on BOTH SIDES of the control bar. The glider simply came apart in his hands as he was standing on launch.

This incorrect assembly did not happen by accident but rather by omission. The PILOT clearly states that he found himself in an environment where his attention was being pulled in many different directions at once, both during assembly and afterwards during his pre-flight.

RECOMMENDATIONS:
This incident resulted in several posts on the club Forum, discussing possible remedies to this potentially fatal FALSE ASSEMBLY of the Falcon 3 downtube/control bar juncture. This investigation is being forwarded to the vendor for further consideration.

One recommendation on the forum was to wrap a ring of red electrical tape around the control bar marking the correct position of the base tube/downtube juncture, making it easier to spot when the assembly is incorrect. Another was to etch the control bar, marking the correct location.

The more important and obvious recommendation is to perform a thorough pre-flight EACH AND EVERY TIME you fly, no matter how many hours of flying you have under your belt. If distractions arise that require you to walk away from your gilder during pre-flight, start from the very beginning when you come back. Are two extra minutes worth your life? Absolutely!

END OF REPORT
Steve Murillo

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JD
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Post by JD » Sun Dec 16, 2012 6:41 pm

Read the well-documented Wills Wing Falcon http://www.willswing.com/pdf/manuals/Fa ... 202009.pdf

Page 16:
While pushing up on the leading edge between the nose and the crossbar junction, step on the bottom side wire with about 75 lbs. of force. This is a rough field test of the structural security of the side wire loop, the control bar, the kingpost, and the crossbar, and will likely reveal a major structural defect that could cause an in-flight failure in normal operation.
This would have probably revealed the issue prior to launch.

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dhmartens
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Post by dhmartens » Sun Dec 16, 2012 11:07 pm

Wills Wing offers a wide range of control bar configurations, each designed to provide the optimum balance of performance, economy and ease of use appropriate for a given glider model and its intended use.
http://www.willswing.com/features/controlBars.asp

"AT Streamlined Downtubes With Folding Basetube (No Longer Used on Production Models)

The Wills Wing AT streamlined downtubes offer enhanced performance over conventional round downtubes in an economical streamlined profile. The folding speedbar basetube option shown speeds set-up and breakdown by eliminating the installation or removal of any nuts or safeties during the process. A more economical, non-folding speedbar is also available.."

I think a cable runs through it which might make it nearly impossible to pop apart.

The wheels become the next issue, possibly some magician like that clip or snap on like magic rings.

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Steve90266
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Big Sur mishap

Post by Steve90266 » Thu Jan 10, 2013 10:11 am

This just in from Steve Pearson, owner of Wills Wing:
We’ve revisited this type of incident many times over the years. We always try to minimize the opportunity for improper assembly but that’s practically impossible with engineering and other design constraints. Mike and I talked about the red tape solution and don’t think that would help for a multitude of reasons, the same type of reasons that no one has ever solved the taking off without hooking in problem. As one example, consider that when you rely on a safety indicator and the indicator malfunctions, is inadequate or missing, you are worse off than not having the indicator to begin with. In this case as in most others, the assembly error would have been caught with a routine pre-flight. I’ll leave you with a few other examples of pretty scary examples of issues that would have been caught with a 30 second preflight. In fact, I can’t think of one example in the history of aviation when the preflight inspection has been engineered out of the assembly sequence.
Forgive me for not posting the examples. I'm not sure how to get the photos in here. The first photo depicted a frayed wire that was down to about two strands, discovered after landing.

The second was a picture of the hold back on a glider not properly seated. The pilot used the little string normally used to grab the hold back AS THE HOLD BACK! I'm going to figure out how to post pictures just so you guys can see this. Discovered AFTER LANDING!! Unbelievable!!
Steve Murillo

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JD
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Re: Big Sur mishap

Post by JD » Thu Jan 10, 2013 11:40 am

Steve90266 wrote:....Discovered AFTER LANDING!! Unbelievable!!
Steve, I am aware of several instances where gliders have fallen apart shortly after landing once the friction from the flight load was removed and unsecured components slipped apart. Even if a hang glider is stored while fully assembled in a climate-controlled hangar, there is still no substitute for an adequate pre-flight inspection before each and every launch.

From what I was told about the Big Sur incident, the pilot was apparently distracted by his camera mount and as a result he did not follow through with the same pre-flight inspection routines and verifications he would have otherwise.

Distractions are in my opinion the single biggest cause of FTHI and improperly assembled gliders and harnesses. Nobody should ever needlessly distract another pilot who is in the middle of an assembly or inspection process of his gear while on launch. Nor should a pilot distract himself either.

Many of the safest pilots I know never follow the exact same routine but vary their assembly and inspection procedures in order to avoid the type of distraction that comes from excessive repetition where we zone out and think we did something because we've done it thousands of times before by following the same routine. Apologies for the long sentence.

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dhmartens
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Post by dhmartens » Thu Jan 10, 2013 7:08 pm

I cannot find a single photo or drawing of a folding base tube anywhere on the internet, only brief mention. It maybe could be improved for pre-flight inspection and adding wheels quickly.

Here's a small drawing.
http://www.willswing.com/pdf/manuals/om ... h_2002.pdf

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TerryH
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Post by TerryH » Sun May 08, 2016 9:08 am

Bumping this thread as a reminder and for people who haven't seen it before, and because it just happened to me.

Yesterday I had the same assembly error, fortunately discovered when I picked up the partially assembled glider to move it out of someone's way. I'm pretty sure I would have caught it at pre-flight time, since I'm bordering on paranoid about this particular "feature" of the Falcon, and I visually inspect that area for correctness AND do the WW "tread on the side wire" test. Still... makes you think...

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Steve90266
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Assembly

Post by Steve90266 » Sun May 08, 2016 11:14 am

Good to know that these discussions can have a positive effect on the community. Thanks for sharing your experience.
Steve Murillo

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