GA SMA HAD HYDRAULIC FAILURE DUE TO INCOMPLETE MAINTENANCE AT FBO.

Narrative

HELI WAS TEST FLOWN BY MYSELF AND ACFT INSPECTOR FROM MD. FLT APPEARED NORMAL IN ALL ASPECTS. ACFT WAS THEN FLOWN AGAIN LATER IN AFTERNOON AS A FOLLOWUP FLT. THAT EVENING; I SPOKE WITH ACFT INSPECTOR WITH REGARDS TO THE ACFT BEING RELEASED FOR FLT AND THE ANNUAL INSPECTION BEING SIGNED OFF BY HIM IN THE ACFT RECORD. HE ASSURED ME THAT THE ACFT WAS RELEASED FOR FLT AND THAT HE WOULD HAVE THE ENTRIES MADE IN THE LOGBOOK LATER THAT DAY. I THEN ASSUMED THAT SINCE WE DID HAVE HIS APPROVAL; THE ACFT WAS LEGAL TO FLY. LATER THAT DAY; THE ACFT HAD AN HYD FAILURE. THE ACFT WAS LANDED W/O INCIDENT. IT WAS LATER DISCOVERED THAT A PLUG IN THE HYD RETURN LINE WAS LEFT IN THE LINE. THIS CAUSED PRESSURE TO BUILD IN THE HYD SYS AND THE LINE TO DISCONNECT AT THE TOP OF THE XMISSION. CORRECTIVE ACTION HAS BEEN TAKEN AND IT IS NOW CLEAR TO ME THAT AN ACFT RELEASED FOR FLT MUST HAVE THE PROPER ENTRIES IN THE LOGBOOK PRIOR TO ANY FURTHER FLT AFTER AN ANNUAL INSPECTION. THERE WAS NO INTENT TO FLY AN ACFT THAT WAS KNOWN TO BE UNAIRWORTHY.