ALTDEV ON ARR PROC DUE TO WRONG ALTIMETER SETTING.

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ON RENNEBUNK ARR TO JFK YOU MUST CROSS TRAIT AT FL240. AFTER THIS YOU CAN EXPECT TO CROSS CALVERTON VOR (CLL 117.2) AT 12000 FT AND 250 KTS. TO MAKE THIS RESTR YOU MUST START DOWN IMMEDIATELY AFTER TRAIT AT FL240. WE RECEIVED CLRNC TO 12000 FT A BIT LATE SO DSCNT WAS STARTED IMMEDIATELY AFTER RECEIPT. ALTIMETERS WERE RESET DURING DSCNT CHK. ATIS AT JFK DID NOT GIVE ALT SETTING SINCE PRESSURE WAS FALLING RAPIDLY. CAPT HEARD ALTIMETER SETTING OF 29.96 FROM ZBW AND READ BACK THE SAME. WE LEVELED AT 12000 FT. CTR THEN ASKED IF WE WERE LEVEL AT 12000 FT. WE THEN HEARD CORRECT ALT SETTING OF 29.26 AND RESET ALTIMETERS. WE IMMEDIATELY NOTED OUR DIFFERENCE IN ALT AND CLBED TO 12000 FT (29.26). NO ACFT CONFLICTS WERE NOTED OR ANNOUNCED BY ATC. I GENERALLY USE THE ALTIMETER SETTING FROM ATIS (DISPLAYED ON TKOF/LAND DATA CARD) TO XCHK ALTIMETER SETTING GIVEN BY ATC. SINCE NONE WAS GIVEN I RELIED SOLELY ON SETTING GIVEN BY ANOTHER CREW MEMBER. HIGH WORKLOAD DISTRACTED FROM MY HEARING ALT SETTING. I WOULD SUGGEST THAT ATIS ALWAYS GIVE ALT SETTING AND THEN INCLUDE NOTES SUCH AS 'PRESSURE FALLING RAPIDLY.' AT LEAST THAT WOULD GET YOU CLOSER TO A CORRECT ALTIMETER SETTING; ESPECIALLY WHEN THE PRESSURE IS LOW. SUPPLEMENTAL INFO FROM ACN 294511: NO ALTIMETER WAS GIVEN ON THE ATIS FOR JFK. INSTEAD; THE COMMENT WAS MADE THAT 'PRESSURE FALLING RAPIDLY.' WHEN CTR GAVE US THE LCL ALTIMETER DURING DSCNT; '29.96' WAS READ BACK. NO CORRECTION WAS GIVEN BY CTLR.