USE OF UNCERTIFIED NAV SYS.

Narrative

I AM A CAPT FOR A LARGE CHARTER CARRIER. OUR COMPANY IS IN THE PROCESS OF CONVERTING TO GPS AS PRIMARY LONG RANGE NAV SOURCE. ON JAN/SUN/95; MYSELF AND MY CREW WERE ASSIGNED A TRIP IN ONE OF THE COMPANY'S NEWEST ACFT ACQUISITIONS; A DC-8-62. THE TRIP OPERATED FROM YIP-EINN- LOWG-ATL WITH CREW REST IN LOWG (GRAZ; AUSTRIA). ON ENTERING THE ACFT; I NOTED THAT THE LONG RANGE NAV EQUIP WAS 2 GPS'S AND 1 OMEGA. MY INITIAL REACTION WAS THAT THIS ACFT MUST BE THE FIRST ONE ON OUR DC-8 FLEET TO BE APPROVED FOR GPS AS PRIMARY NAV. THE UNITS PERFORMED FLAWLESSLY DURING THE XING EBOUND AND WBOUND. MY FO FOR THIS TRIP HAD MADE ONLY 1 ATLANTIC XING PRIOR TO THIS TRIP AND WE SPENT A GOOD DEAL OF TIME ENRTE DISCUSSING PROCEDURAL AND EQUIP QUESTIONS. I WAS ABLE TO ANSWER MOST OF HIS QUESTIONS WITHOUT REFING A BOOK UNTIL WE GOT TO SOME FAULT CODES ON THE GPS. WHEN I CHKED OUR SHIP'S LIBRARY; I COULD FIND NO GPS MANUAL ON BOARD. I THOUGHT IT UNUSUAL NOT TO HAVE A MANUAL FOR THE PRIMARY NAV SYS AND STARTED TO CONSIDER THE POSSIBILITY THAT THE GPS HAD NOT YET BEEN APPROVED. I CHKED OUR COMPANY OPS SPECS TO CONFIRM MY SUSPICIONS. AS WE WERE ALREADY IN MID XING ON THE RETURN LEG; I ELECTED TO CONTINUE IN THE MNPS AS THE UNITS WERE NAVING WELL. WHILE I MUST ACCEPT BLAME FOR NOT KNOWING THAT OUR COMPANY HAD NOT RECEIVED FINAL APPROVAL FOR GPS; I THINK THAT I HAVE A RIGHT TO EXPECT THAT AN ACFT ASSIGNED BY DISPATCH AND RELEASED BY MAINT IS IN FACT AIRWORTHY AND LEGAL FOR THE TRIP TO WHICH IT HAS BEEN ASSIGNED. MY PERSONAL ACTION IN THIS MATTER WAS TO DISCLOSE THE ERROR TO THE COMPANY AND THEY HAVE INDICATED THAT THEY WILL DISCLOSE TO THE FAA. WE ARE ALSO KEEPING THE ACFT IN QUESTION OFF INTL SVC UNTIL OUR GPS PROGRAM HAS FAA APPROVAL.