Minooka Accident?

That's very interesting... where can one find this 'History'?


On Monday, August 15, 2016 at 6:33:59 PM UTC-4, FZ wrote:
There is a history of collapsing of the back rest in SZD-55.
Mine was equipped by the previous owner with a custom made wood inserts, supposedly preventing of such events. Collapsing of the back rest would certainly cause pilot to fall back and sudden back pull on the stick.
Following stall would be consistent with this scenario.

If my back support was being reinforced with wooden blocks I would assume something was broken and it would not be flown until fixed!

Regards,

Bob 7U

On Tuesday, August 16, 2016 at 7:40:38 AM UTC-4, wrote:
That's very interesting... where can one find this 'History'?


On Monday, August 15, 2016 at 6:33:59 PM UTC-4, FZ wrote:
There is a history of collapsing of the back rest in SZD-55.
Mine was equipped by the previous owner with a custom made wood inserts, supposedly preventing of such events. Collapsing of the back rest would certainly cause pilot to fall back and sudden back pull on the stick.
Following stall would be consistent with this scenario.

If my back support was being reinforced with wooden blocks I would assume something was broken and it would not be flown until fixed!

Regards,

Bob 7U

We are not talking here of some broken parts or wooden blocks.
The back-rest is adjustable by moving of two rails into one of few positions/cutouts/notches. Fixed pins go into notches and should stay there by the virtue of two springs pulling the rails downward. Sit stays put.
Given some unusual movement of pilot ( see dropped wing twice, some action inside a cockpit) it may happen that the springs are not pulling the rail strong enough to keep the rail in the selected position.
To prevent this from happening you will insert into the rails two long pieces of plastic or wood of certain shape. It positively prevent the movement of rails and back-rest.
I don't know if this is a factory part or some custom made improvement. SZD manual do not say anything on sit adjustment. It would be a good idea to ask the manufacturer.

On Tuesday, August 16, 2016 at 5:29:50 PM UTC-4, FZ wrote:
On Tuesday, August 16, 2016 at 7:40:38 AM UTC-4, wrote:
That's very interesting... where can one find this 'History'?


On Monday, August 15, 2016 at 6:33:59 PM UTC-4, FZ wrote:
There is a history of collapsing of the back rest in SZD-55.
Mine was equipped by the previous owner with a custom made wood inserts, supposedly preventing of such events. Collapsing of the back rest would certainly cause pilot to fall back and sudden back pull on the stick.
Following stall would be consistent with this scenario.

If my back support was being reinforced with wooden blocks I would assume something was broken and it would not be flown until fixed!

Regards,

Bob 7U

We are not talking here of some broken parts or wooden blocks.
The back-rest is adjustable by moving of two rails into one of few positions/cutouts/notches. Fixed pins go into notches and should stay there by the virtue of two springs pulling the rails downward. Sit stays put.
Given some unusual movement of pilot ( see dropped wing twice, some action inside a cockpit) it may happen that the springs are not pulling the rail strong enough to keep the rail in the selected position.
To prevent this from happening you will insert into the rails two long pieces of plastic or wood of certain shape. It positively prevent the movement of rails and back-rest.
I don't know if this is a factory part or some custom made improvement. SZD manual do not say anything on sit adjustment. It would be a good idea to ask the manufacturer.

Someone should check the wreck if there is anything there to help jamming adjustment of the back rest.
Ship was designed for too easy adjustment,maybe for club fliers.
I lock it by 2 1 foot long 1/4 inch thick plexiglass sticks with springs on the ends for locking on the end of tracks.
It looks like a factory made.
Other point of interest is the clip holding down ruder.
I found this piece many times missing or badly corroded,by pilots urine.
Ryszard Krolikowski RW

Yes, for sure, someone in the Chicago club should take a look at the wreckage to see if the seat back is broken. If it is, then contact the investigators (NTSB & FAA) and tell them what was found. I was at the field when a G-103 flew into the cliff, short of the runway. All the Federalli was interested in was checking AD's and to see if the ship was in annual. Glider pilots found the cause which was spoiler opened too far because of a worn stop, resulting in spoiler plate jammed on top of wing skin. Also, fill out a malfunction or defect report with your findings and send it to your local Feds and NTSB.
JJ