ACFT EQUIP PROB. NAV EQUIP. FO'S HSI (HDG) ERROR AND OMEGA ERROR. ONLY RELIABLE NAVAID IN ACFT AT DEST WAS NDB. MULTIPLE HDG NAV PROBS.

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LOCATION: JFK NORTH AMERICA AND SFO. DEP JFK MAR/XX/96 FLT XX; D10 JFK TO SFO. COPLT FLYING. COPLT'S DIRECTIONAL GYROSCOPE SHOWED 060 DEGS. HDG ASSIGNED BY DEP CTL. WHILE CAPT'S DIRECTIONAL GYROSCOPE; HSI; SHOWED 100 DEGS; CAPT CHKED WHISKY COMPASS AND CONFIRMED CAPT'S COMPASS CORRECT. RESET; QUICK ALIGN ON FO DIRECTIONAL GYROSCOPE AND CORRECTED HDG 40 DEG L TO 060 DEGS. ATC NOTED CORRECTION. CAPT ADVISED ATC OF PROB AND THAT IT APPEARED CORRECTED. FLT CONTINUED IN CRUISE THE #2 OMEGA FLYING AUTOPLT GAVE A XTRACK ERROR OF 4 MI AND WIND READ OUT DIFFERENT FROM #1 OMEGA OF 100 KTS. OMEGAS PRECISION UPDATE OVER THE NEXT VOR AND APPEARED NORMAL FOR AN HR; THEN WE SAW HSI COMPASS DIFFERENCE OF 30 DEGS. NO ONE CHKED WRONG AGAINST WHISKY COMPASS AND AFTER REALIGN WOULD ONLY FUNCTION IN THE DIRECTIONAL GYROSCOPE MODE. CONTINUED FLT WITH #1 IN DIRECTIONAL GYROSCOPE; #2 IN NAV AND XCHKED BOTH AGAINST WHISKY COMPASS EVERY 5 MINS; THEN #2 OMEGA DIVERGED EXCESSIVELY FROM #1. WE ADVISED ATC OF NECESSITY TO NAV BY VOR DUE UNRELIABLE OMEGAS. CONTINUED TO SFO BY XCHKING #1 AND #2 DIRECTIONAL GYROSCOPE AGAINST THE WHISKY COMPASS. ON APCH SFO UNITS PRECESSING SO RAPIDLY WE ASKED FOR AND RECEIVED RADAR VECTORS FOR VISUAL AT SFO AT THIS TIME ALL NAV EXCEPT NDB UNRELIABLE. ENTERED ALL IN LOGBOOK. NEED FOLLOW UP INFO PLEASE. I AM VERY MUCH INTERESTED IN CAUSE OR CAUSES THESE NAV UNIT FAILURES. FLT SAFE BUT TRACK MAINT WAS DIFFICULT AND WORKLOAD VERY HIGH.