A BE95 ACFT DECLARED EMER AND RETURNED TO DEP ARPT WHEN #1 ENG FAILED TO UNFEATHER FOR AIR START DURING MULTI-ENGINE TRAINING. UNFEATHERING ACCUMULATOR SUSPECT.

Narrative

ON A MULTI-ENG TRAINING FLT (DURING WHICH I WAS THE STUDENT) THE L ENG (#1) WAS FAILED INTENTIONALLY; AND SECURED AS PER PROC SET FORTH BY THE MANUFACTURER. UPON BEGINNING RESTART PROC; IT WAS OBSERVED THAT THE UNFEATHERING ACCUMULATOR WAS INOPERABLE; AND THAT IT ALONE WOULD NOT RESTART THE ENG. AN AIR START WAS ATTEMPTED AND THE ENG WOULD NOT START. BEING SOUTH OF ZZZ AS THE CLOSEST ARPT; WE DECLARED AN EMER AND LANDED ZZZ ON 1 ENG. ZZZ1 HAD AN EMER VEHICLE ON-SITE. AFTER LNDG AND SECURING THE AIRPLANE; WE ATTEMPTED A RESTART OF THE INOPERABLE ENG AND IT DID START. AFTER A TRIP TO MAINT AND A SUCCESSFUL RUN-UP; WE RETURNED TO ZZZ WITH BOTH ENGS OPERABLE. THERE WERE NO INJURIES; AND WE 'WAIVED OFF' THE EMER SHORTLY AFTER LNDG ZZZ AND GETTING THE OTHER ENG RUNNING. MAINT BELIEVES THE ISSUE TO BE WORN MAIN BEARINGS LETTING OIL PRESSURE ESCAPE THROUGH THE CRANK AND BEARINGS RATHER THAN BEING PROPERLY DIRECTED FROM THE ACCUMULATOR DIRECTLY TO THE PROP HUB. THE ACCUMULATOR TESTED FINE; WITH FULL PRESSURE AS PER THE MANUFACTURER'S SPEC. THE ENG WOULD NOT RESTART IN THE AIR; DUE MOST LIKELY TO THE LARGE AMOUNTS OF DRAG ASSOCIATED WITH ATTEMPTING TO START AN ENG WITH A FULLY FEATHERED PROP. IT DID START SUCCESSFULLY ON THE GND; AND DID OPERATE PROPERLY AFTERWARD. ANOTHER ENG SHUTDOWN THE NEXT DAY SHOWED THE SAME PROB TO BE OCCURRING; BUT THIS TIME THE SHUTDOWN WAS ACCOMPLISHED IN THE PATTERN AT ZZZ WITH ATC ADVISED. THERE WAS NO EMER DECLARED DURING THAT FLT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THESE ENGINES HAVE TWO-BLADED PROPS WITH VARIABLE PITCH PROP AND HYD GOVERNOR. THIS ACFT HAS AFTER MARKET ACCUMULATORS. MOST BE-95 TRAVELAIRS DO NOT HAVE PROP UNFEATHERING ASSIST ACCUMULATORS. THEY ARE REPLACING ALL RAYJAY FLEX HOSES (4) EACH PER ENGINE DUE TO AN AIRWORTHINESS DIRECTIVE THAT JUST RECENTLY TERMINATED; REQUIRING ALL RAYJAY FLEX HOSES BE REPLACED WITHIN FIVE YEARS. THESE HOSES ALSO CONNECT TO THE UNFEATHERING ACCUMULATOR. THE FALL BACK PROCEDURE TO UNFEATHER A PROP WITH AN INOP ACCUMULATOR SYS IS TO ADD EXTRA FUEL MIXTURE AND USE STARTER IN FLIGHT TO 'QUICK' START THE ENGINE AND GET OIL PRESSURE UP TO UNFEATHER THE PROP.