AN A319 DEPARTING JFK GATE; RWY 31L FULL LENGTH; EXPERIENCED DUAL IRU FAILURES (#2 AND #3) AT ROTATION.

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ON OCT/TUE/2004; XA00Z ON TKOF ROLL RWY 31L JFK. LATE TKOF ROLL DUAL INERTIAL REFERENCE UNIT FAILURES #2 AND #3. FO WAS FLYING; WE CONTINUED THE TKOF ROLL AND SHORTLY AFTER GETTING AIRBORNE FO LOST PRIMARY FLT DISPLAY AND NAVIGATION DISPLAY ON HIS SIDE. I; THE CAPT TOOK OVER CTL FLYING. WE ALSO LOST CAPT'S FLT DIRECTOR; BOTH AUTOPLTS AND AUTOTHRUST. ACFT REVERTED TO ALTERNATE LAW FLT CHARACTERISTICS. WE CONFERRED WITH DISPATCH AND DECIDED TO RETURN TO JFK FOR LNDG. WE DECLARED AN EMER. AFTER LNDG GEAR WAS LOWERED ACFT REVERTED TO DIRECT LAW FLT AS ADVERTISED. LNDG WAS UNEVENTFUL. TAXIED BACK TO GATE. WE AS FLT CREW WERE UNAWARE OF THIS PROB WITH INERTIAL REFERENCE FAILURES AT JFK USING FULL LENGTH RWY 31L FOR TKOF. MAINT INFORMED US THIS HAS HAPPENED AT LEAST A DOZEN TIMES IN THE PAST 2 YRS. THERE SHOULD BE SOMETHING IN THE SYSTEM TO NOT ALLOW A319'S FROM USING RWY 31L AT JFK FULL LENGTH UNTIL SOMEONE RESOLVES THIS ISSUE. EVIDENTLY IT IS ALWAYS AN A319 USING RWY 31L FULL LENGTH AFTER DEPARTING GATE AT JFK. (USUALLY ONLY ONE INERTIAL REFERENCE UNIT FAILS.) THIS COULD BE VERY DANGEROUS IN IFR WITH DUAL INERTIAL REFERENCE UNIT FAILURES. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR SAID HIS AIRLINE NOW PUTS A RESTRICTION ON USING RWY 31L FULL LENGTH. THAT NOTICE IS IN THE REMARKS SECTION OF THE RELEASE. HIS COMPANY MAINT STATED THAT AIRBUS 319 DEPARTURES FROM SPECIFIED GATE USING RWY 31L FULL LENGTH HAVE HAD THIS PROB BEFORE. FOLLOWING THIS INCIDENT; MAINT RESET THE COMPUTERS; REALIGNED IRU'S AND RELEASED THE AIRPLANE. THE CREW DEPARTED AGAIN ON RWY 31L BUT TAXIED PAST TXWY 'Y' INTERSECTION BEFORE INITIATING TKOF. THE RPTR COULD NOT SPECULATE ON A CAUSE BUT THEY HAD DISCUSSED THE ROUGH RWY OR A MAGNETIC MASS IN THE GATE VICINITY. THE RPTR STATED THAT HE WAS SURPRISED BY THE CTL RESPONSES IN DIRECT LAW. THE ACFT WAS SLOW TO RESPOND AND FELT MUSHY.