Narrative:

Departing sfo from runway 28R full length; eugen 5 departure en route to mry under IFR flight plan in clear WX. The SID calls for a climb via the sfo 281 degree radial; after passing the 6 DME fix and reaching 2000 ft; turn left to intercept and proceed via sau 168 degree radial to eugen; etc.... We engaged the autoplt and flew the departure coupled to the FMS. Reaching 3 DME at 2500 ft; the aircraft initiated a turn to the left. Before we could take corrective action; norcal called us remarking the early turn and assigned a heading; then assigned the next frequency for norcal; no further discussion ensued. When back to base; we called and reported the difference between the commercial chart supplier plates eugen 5 departure and the action taken by the autoplt; based on FMS database. They investigated and called back the next day stating that they flew the departure multiple times on their simulator and found no discrepancies. A few days later; another gentleman from company was assigned the problem to investigate further. He stated that he needed to know the software version of the FMS; as an older software version might have an issue with an unusual departure as the eugen 5 from sfo. Apparently it is one of the few departures that does not fly to determined fixes; but instead assigns an intercept to a radial inbound to the fixes; twice in a row.

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Original NASA ASRS Text

Title: C550 WITH UNIVERSAL FMS FAILS TO MEET SFO 281 DEG RADIAL; 6 DME REQUIREMENT OF EUGEN DEP FROM SFO.

Narrative: DEPARTING SFO FROM RWY 28R FULL LENGTH; EUGEN 5 DEP ENRTE TO MRY UNDER IFR FLT PLAN IN CLR WX. THE SID CALLS FOR A CLB VIA THE SFO 281 DEG RADIAL; AFTER PASSING THE 6 DME FIX AND REACHING 2000 FT; TURN L TO INTERCEPT AND PROCEED VIA SAU 168 DEG RADIAL TO EUGEN; ETC.... WE ENGAGED THE AUTOPLT AND FLEW THE DEP COUPLED TO THE FMS. REACHING 3 DME AT 2500 FT; THE ACFT INITIATED A TURN TO THE L. BEFORE WE COULD TAKE CORRECTIVE ACTION; NORCAL CALLED US REMARKING THE EARLY TURN AND ASSIGNED A HDG; THEN ASSIGNED THE NEXT FREQ FOR NORCAL; NO FURTHER DISCUSSION ENSUED. WHEN BACK TO BASE; WE CALLED AND RPTED THE DIFFERENCE BTWN THE COMMERCIAL CHART SUPPLIER PLATES EUGEN 5 DEP AND THE ACTION TAKEN BY THE AUTOPLT; BASED ON FMS DATABASE. THEY INVESTIGATED AND CALLED BACK THE NEXT DAY STATING THAT THEY FLEW THE DEP MULTIPLE TIMES ON THEIR SIMULATOR AND FOUND NO DISCREPANCIES. A FEW DAYS LATER; ANOTHER GENTLEMAN FROM COMPANY WAS ASSIGNED THE PROB TO INVESTIGATE FURTHER. HE STATED THAT HE NEEDED TO KNOW THE SOFTWARE VERSION OF THE FMS; AS AN OLDER SOFTWARE VERSION MIGHT HAVE AN ISSUE WITH AN UNUSUAL DEP AS THE EUGEN 5 FROM SFO. APPARENTLY IT IS ONE OF THE FEW DEPS THAT DOES NOT FLY TO DETERMINED FIXES; BUT INSTEAD ASSIGNS AN INTERCEPT TO A RADIAL INBOUND TO THE FIXES; TWICE IN A ROW.

Data retrieved from NASA's ASRS site as of January 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.