Narrative:

About 2 1/2 hours after departing; the oil pressure on #3 engine began to fluctuate and then drop into the red. We were on a random route with the tracks to our north. We shut down #3 engine and completed the memory checklist items; turned south off our route and began a descent as the aircraft would not maintain FL430 on 2 engines. As the PF continued the descent; the PNF called ATC and declared an emergency and requested clearance back to ZZZZ. The PNF also broadcast on 123.45 our position and altitude for other aircraft (should have broadcast on 121.5 as well). We leveled off at FL360; received clearance back to ZZZZ; and completed the engine failure in-flight abnormal procedures checklist. The flight back to ZZZZ was uneventful. As we prepared for the approach and landing; we reviewed the approach and landing with 1 engine inoperative abnormal procedures checklist. The approach and landing were uneventful with clear sky and unlimited visibility. After clearing customs; maintenance opened the #3 cowl (which showed evidence of an oil leak) and discovered the oil chip detector had become disconnected allowing the oil to vent overboard. Upon further inspection; it was also discovered that a tie wrap was imposing a counterclockwise moment on the chip detector which could have caused it to disconnect. There is no provision to safety the chip detector in place! If the chip detector had a safety device (safety wire) in place; this situation would not have occurred!

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Original NASA ASRS Text

Title: DA50 CAPT REPORTS OIL PRESSURE LOSS ON CENTER ENGINE OVER ATLANTIC. EMERGENCY IS DECLARED WITH DIVERSION TO ALTERNATE.

Narrative: ABOUT 2 1/2 HRS AFTER DEPARTING; THE OIL PRESSURE ON #3 ENG BEGAN TO FLUCTUATE AND THEN DROP INTO THE RED. WE WERE ON A RANDOM RTE WITH THE TRACKS TO OUR N. WE SHUT DOWN #3 ENG AND COMPLETED THE MEMORY CHKLIST ITEMS; TURNED S OFF OUR RTE AND BEGAN A DSCNT AS THE ACFT WOULD NOT MAINTAIN FL430 ON 2 ENGS. AS THE PF CONTINUED THE DSCNT; THE PNF CALLED ATC AND DECLARED AN EMER AND REQUESTED CLRNC BACK TO ZZZZ. THE PNF ALSO BROADCAST ON 123.45 OUR POS AND ALT FOR OTHER ACFT (SHOULD HAVE BROADCAST ON 121.5 AS WELL). WE LEVELED OFF AT FL360; RECEIVED CLRNC BACK TO ZZZZ; AND COMPLETED THE ENG FAILURE INFLT ABNORMAL PROCS CHKLIST. THE FLT BACK TO ZZZZ WAS UNEVENTFUL. AS WE PREPARED FOR THE APCH AND LNDG; WE REVIEWED THE APCH AND LNDG WITH 1 ENG INOP ABNORMAL PROCS CHKLIST. THE APCH AND LNDG WERE UNEVENTFUL WITH CLR SKY AND UNLIMITED VISIBILITY. AFTER CLRING CUSTOMS; MAINT OPENED THE #3 COWL (WHICH SHOWED EVIDENCE OF AN OIL LEAK) AND DISCOVERED THE OIL CHIP DETECTOR HAD BECOME DISCONNECTED ALLOWING THE OIL TO VENT OVERBOARD. UPON FURTHER INSPECTION; IT WAS ALSO DISCOVERED THAT A TIE WRAP WAS IMPOSING A COUNTERCLOCKWISE MOMENT ON THE CHIP DETECTOR WHICH COULD HAVE CAUSED IT TO DISCONNECT. THERE IS NO PROVISION TO SAFETY THE CHIP DETECTOR IN PLACE! IF THE CHIP DETECTOR HAD A SAFETY DEVICE (SAFETY WIRE) IN PLACE; THIS SITUATION WOULD NOT HAVE OCCURRED!

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.