Awhile back flydog posted an accident report on lonesomebuzzards.com for G-CCAJ. The crash was caused by pilot error but the investigators pointed out two things related to the shoulder harness that seem rather significant.
The most significant thing the investigators point out are the broken shoulder harness cables and why they broke.
The report states that the cable broke where they make a 90° bend in the elevator control bracket.
The suggestion was to change how the cable is mounted to maintain a proper bend radius as recommended by the cable manufacturer.
The other noteworthy item is that the builder did not attach the cables to the shoulder harness according to plan. Instead of one cable looped through the eyelet on the shoulder harness using a thimble this builder has simply put a thimble on the end of each cable and then connected both cables and both shoulder harness with a single shackle. This turned out to be a potential improvement. The investigators noted that this likely contributed to keeping the shoulder harness from slipping off the pilots shoulders.
Not wanting my safety devices to fail when they are needed most I decided to learn from this accident and improve my airplane.
I first started with the elevator cable bracket at the rear of the fuselage by drilling four holes. Two on the top and two on the front.
I then cut off the excess material the is not needed.
Next I installed the thimbles for the cable.
Both cables were attached and crimped then installed into the fuselage.
On the other end both cables were attached to both shoulder harnesses. Getting both cables the same length was a little difficult.