Glider crash near Reno yesterday

On Friday, September 28, 2018 at 9:03:54 AM UTC-7, wrote:
What pieces of the wreckage were retrieved?...

The NTSB preliminary report contains a picture of the wreckage. Its condition makes clear that only the metal parts, and only some of those, will provide any meaningful clues.

Maybe a tool left under the seat, which eventually jammed the elevator?

Could be that. Given the facts of the last known location and direction of the glider, and the fact that it had enough kinetic energy to perform the maneuvers described, my speculation would be towards a progressive elevator system interference that first made it difficult to reduce speed (hence enough airspeed to perform two successive loops), and after it was overcome, then locked the elevator in the full nose up deflection.

My thinking, and this is raw speculation based on only a few facts available on the surface, is this: Sergio and Jim might have started experiencing elevator control interference while loitering near Mt. Rose for the start of the task. So they headed for Carson City across the Washoe valley where they would have many more opportunities for landing than in the rough and densely timbered environment around Truckee. At some point the interference got so bad that the speed could not be reduced, and the glider accelerated. At that point, a strong pull to the stick overcame the resistance, and the stick went immediately to the aft stop. Then whatever caused the initial interference locked the stick in that position.

Again, this is pure speculation with little or no intrinsic value. However, it invites the question: What would I do in that situation? How long is it prudent to troubleshoot and explore limits?

A close inspection of the burned out wreckage may reveal any unusual metal tool.

That is as I am hoping. This is a very disquieting accident, and I hope that the NTSB and interested parties arrive at a clear probable cause.

--Bob K.

What's your point?Â* During that time, the G loading would not be nearly
as high as at the bottom of the loop.Â* A quarter roll, then, would take
about 3 seconds, not a big deal.Â* I'm betting they were unconscious or
highly disoriented/disabled after the initial maneuver.

On 9/28/2018 10:41 AM, Tango Whisky wrote:
On an ASK 21, a half roll takes 6 seconds, and I wouldn't expect a Duo to roll any faster.

--
Dan, 5J

In my brothers situation it was at the top of the second loop that he was able to get enough of the canopy kicked out to crawl over the side. His bailout was at about 700 ft agl, his chute bairly opened in time to arrest his decent. He ended up with facial lacerations and a busted ankle. The ventus performed two more loops without him aboard and dang near landed itself about 400 ft from where my brother landed. A busted canopy, busted elevator and tail boom is all that was damaged. That bird was flying again in about 6 weeks.

On Fri, 28 Sep 2018 09:03:52 -0700 (PDT), wrote:

On Thursday, September 27, 2018 at 12:01:38 PM UTC-7, wrote:
I agree that this appears to be an elevator failure. What pieces of the wreckage were retrieved? Was the horizontal stabilizer/elevator retrieved? Was the elevator bolt located (ripped out of the elevator, found in a side pocket, found in the trailer, etc). I have the ability to fly my Phoenix low level over the site on a suitable light east wind day and do a close search for the horizontal stab if it is missing. Finding the stab may be the key to solving this tragedy.


Maybe a tool left under the seat, which eventually jammed the elevator? A close inspection of the burned out wreckage may reveal any unusual metal tool.


This year a friend of mine had an incident in an old Duo Discus (not
one with the XL fuselage):


They had been missing sime tool (afaik the tool to assemble the
horizontal tail) for weeks and were unable to find it.

I'm not sure anymore about the details, but they found the tool close
to the forward stick mechanism after they had disassembled the forward
seat pan, and my friend said that anyone had agreed that it could have
easily jammed the stick. It was impossible to find it during the
preflight check.

If someone is interested in the details I could call my friend and
post them here.


I'd be very surprised if something else than a blocked stick by FOD
was the cause for this accident.



Cheers from Germany
Andreas

On Monday, September 3, 2018 at 11:09:46 AM UTC-7, bumper wrote:
Another tragic accident yesterday near Slide Mountain. Responders haven't reached the crash site as of this morning due to fire. There are conflicting reports from witnesses and unconfirmed info. Here's a link to the KOLO TV News report:

http://www.kolotv.com/content/news/P...?ref=hvper.com

These were both good friends of mine and I do not with to add to the speculation (and I was not there that specific weekend), but regarding assembly, this Duo was commonly assembled at the beginning of the season and left assembled and covered throughout the season. It is my belief that it was assembled in late May or early June and left that way until the incident. It is possible that some disassembly was done for maintenance or whatever from time to time. According to the people there, the Duo was flown the day before without incident, and was not disassembled overnight. This does not eliminate assembly error entirely, but makes it seemly less likely.

I don’t know about the duo, but the standard Discus 2 elevator has a push rod that exits the front fuselage at the left side where it passes through a bulkhead. I experienced partial elevator jamming in level flight in rough air and it was finally found (by Fidel in Moriarty) as a lost antenna (a small telescopic one with a BNC connector). The push rod can be jammed there by relatively small loose objects.

Having said that, I wonder if there would be enough elevator authority to initiate the reported loops?

Mike

On Tuesday, 4 September 2018 04:09:46 UTC+10, bumper wrote:
Another tragic accident yesterday near Slide Mountain. Responders haven't reached the crash site as of this morning due to fire. There are conflicting reports from witnesses and unconfirmed info. Here's a link to the KOLO TV News report:

http://www.kolotv.com/content/news/P...?ref=hvper.com

Since they were, for a long time, well over the height where supplementary oxygen is needed, there is a very real possibility that they both blacked out. This would explain everything. No one at the wheel.

On Saturday, September 29, 2018 at 4:49:54 AM UTC-7, wrote:
On Tuesday, 4 September 2018 04:09:46 UTC+10, bumper wrote:
Another tragic accident yesterday near Slide Mountain. Responders haven't reached the crash site as of this morning due to fire. There are conflicting reports from witnesses and unconfirmed info. Here's a link to the KOLO TV News report:

http://www.kolotv.com/content/news/P...?ref=hvper.com

Since they were, for a long time, well over the height where supplementary oxygen is needed, there is a very real possibility that they both blacked out. This would explain everything. No one at the wheel.

I very much doubt that. XC had MH oxygen equipment which warns of faults including not breathing. Both were experienced mountain pilots who flew almost exclusively there. One was quite fit, and being at 14,500 ft as reported, even for days, would not be incapacitating without oxygen for him.

A foreign object blocking/jamming a control as a cause in ALL these accidents seems highly unlikely to me.

On Saturday, September 29, 2018 at 7:31:20 PM UTC-6, Bojack J4 wrote:
A foreign object blocking/jamming a control as a cause in ALL these accidents seems highly unlikely to me.

Count the number of lamination's in the tail boom, on these long wing sailplanes, against the factory's layup schedule. Check Renny's V3 as well.

Something seems amiss.

Mike