Originally Posted by
GrayHorizonsHeli
Looking at the pic they show, there is significant damage to the couplings.... find it hard to believe that bolts could have fallen out...
Years ago under the Aerospatiale logo there was a "similar" rash of incidents/accidents with the 350/355 driveshaft flex couplings. Don't recall the specifics but believe it was the bolt tensile strength or something else that caused the bolt/nut to lose torque leading to bolt failure. The fix was to replace all the bolts with known good bolts marked with baby blue paint on the heads and a repetitive tq-check and bushing check on the disc packs. Unfortunately it doesnt need the bolts to fall out to have a failure which unfortunately again looks similar to the above pics.