AT72 EXPERIENCES UNWANTED PROP AUTOFEATHER DURING DSCNT IN HRL AIRSPACE.

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IN THE DSCNT FROM FL240 TO 2000 FT AT APPROX 14000 FT; THE #1 ENG EEC FAULTED AND THE #1 PROP FEATHERED. THE PWR WAS APPROX 50-55% AT THE TIME AND AIRSPD WAS APPROX 240 KIAS -- SMOOTH RIDE NO TURB. WE RAN THE QRH FOR THE EEC; BUT IT WOULD NOT RESET. WE TRIED SEVERAL TIMES TO UNFEATHER THE PROP; BUT IT WOULD NOT. (THE ENG WAS RUNNING AT IDLE.) WE DECIDED TO LEVEL OFF AT 5000 FT AND HOLD TO CALL COMPANY AND RESEARCH THE PROB. I WAS FLYING AND THE CAPT WAS RUNNING THE CHKLISTS. AFTER 1 TURN IN THE HOLD; THE COMPANY AND WE DECIDED THE APPROPRIATE MEASURES WERE TO LAND THE ACFT WITH THE PROP FEATHERED. AT THAT TIME THE ENG SPOOLED UP AND THE PROP UNFEATHERED BY ITSELF. WE LANDED WITH NO MISHAP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT; FOLLOWING THIS INCIDENT THE ENG; PROP ASSEMBLY; AND AUTOFEATHER COMPUTER WERE REPLACED; BUT THE SAME PROB OCCURRED ON SUBSEQUENT TEST FLTS. MAINT FINALLY LOCATED THE SOURCE OF THE PROB IN A WIRING BUNDLE BEHIND THE BAGGAGE COMPARTMENT. TO HIS KNOWLEDGE; NO OTHER SIMILAR INCIDENTS HAVE OCCURRED ON THE AT72.