BE35 AT CRUISE BEGAN TO SHAKE AFTER PENETRATING LIGHT TURB. RETURN TO LAND. INSPECTION SHOWED TAIL SECTION BULKHEAD CRACKED IN 4 PLACES.

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DURING CRUISE FLT THE ACFT BEGAN TO SHAKE. AFTER PENETRATING LIGHT TURB; I SLOWED THE ACFT AND RETURNED TO THE ARPT (APPROX 10 MI). LOOKING INTO THE TAIL SECTION I FOUND THAT BULKHEAD 256.9 LOCATED IN THE TAIL HAD CRACKED IN 4 PLACES. AFTER A REPRESENTATIVE OF BEECHCRAFT DISMANTLED THE TAIL; HE CONCLUDED THAT THE BULKHEAD WAS TOO LIGHT AND NEEDED TO BE REPLACED WITH THE LATER DOUBLED BULKHEAD. THIS PROB EXISTS ON THE EARLY BONANZAS 35; A35; AND EARLY B35 WITH SINGLE BULKHEADS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THE FACTORY SENT THEIR PEOPLE TO DISMANTLE THE ACFT AND COULD FIND NO REASON FOR THE FAILURE. THERE HAVE BEEN 7 OF THESE SAME FAILURES IN 12 MONTHS AND BEECH IS VERY INTERESTED IN CHKING OUT THE PROB. THE ACFT IS VERY WELL MAINTAINED AND THAT IS WHY THEY ARE SO INTERESTED. THE OTHER ACFT THEY COULD ACCOUNT FOR SOME OF THE CRACKING DUE TO RIGGING AND LESS MAINT. THE FACTORY HAS BEEN VERY GOOD AT KEEPING IN TOUCH WITH RPTR AND KEEPING HIM AWARE OF ANY PROGRESS. THEY ARE VERY EAGER TO FIND OUT WHAT IS CAUSING THE PROB. THE FAA IS INVOLVED AS WELL. THIS IS A STRAIGHT 35 MODEL.