MD80 CREW HAD A FAILED FO CENTRAL AIR DATA COMPUTER THAT GAVE ERRONEOUS READINGS ON THE FO'S INSTRUMENTATION.

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ALL GND OPS NORMAL. WX; VFR CONDITIONS AT MCO. DEPARTING RWY 18L. TKOF GND ROLL WAS NORMAL UP TO ABOUT 10-15 KTS PRIOR TO V1. AT THIS TIME; FO INSTS HAD AN INTERMITTENT INDICATION OF FULL SCALE AIRSPD; ALTIMETER RAPIDLY WINDING UP AND VSI INDICATING CLB CONDITION. THE INSTS RETURNED TO MATCH THE CAPT'S INSTS AFTER ABOUT 1-2 SECONDS. CAPT AND STANDBY INSTS AGREED WITH EACH OTHER AND APPEARED ACCURATE THROUGHOUT FLT. NORMAL ROTATION AND CLBOUT THROUGH GEAR UP WERE ACCOMPLISHED. PASSING ABOUT 1000 FT; FO INSTS AGAIN GAVE SAME ERRONEOUS INDICATIONS AS ABOVE FOR ABOUT 1-2 SECONDS. CONTINUED WITH NORMAL PROCS OF HALF RATE; FLAPS UP AND CLB PWR. WE SUSPECTED A PITOT STATIC PROB AND WERE CONCERNED ABOUT THE ACFT WASH THAT WAS COMPLETED THE NIGHT BEFORE. CAPT DECIDED TO RETURN TO MCO FOR MAINT. APPROX 2000-3000 FT; THE FO INSTS FROZE WITH THE FOLLOWING INDICATIONS: AIRSPD PEGGED AT FULL SCALE; ALTIMETER AT 10000 FT; AND VSI AT 1000 FT CLB. ADDITIONALLY; FMA ALT WINDOW WAS BLANK AND DFGC ALT SELECTOR WINDOW WAS BLANK. THE INSTS REMAINED FROZEN UNTIL LNDG GND ROLL WHEN THEY RETURNED TO NORMAL. CAPT FLEW A NORMAL PATTERN FOR AN ILS RWY 18R AND COMPLETED A NORMAL LNDG. AT THE GATE; MAINT COULD NOT FIND ANY PROB WITH THE ACFT. THEY ACCOMPLISHED A BITE CHK ON THE CDC #2 AND IT CHKED NORMAL. THEY STILL SUSPECTED A COMPUTER PROB; SO THEY REPLACED THE CDC #2 ANYWAY AND CHKED THE PITOT STATIC SYS FOR LEAKS (NONE FOUND). ONCE REPAIRED; WE FLEW THE ACFT UNEVENTFULLY TO LGA. SUPPLEMENTAL INFO FROM ACN 589680: AFTER WATCHING THE GND CREW'S TAPING OFF ALL ACFT OPENINGS; THE PREVIOUS NIGHT IN PREPARATION FOR ACFT WASHING; I SUSPECTED THAT SOME OF THE STATIC PORTS WERE STILL COVERED. WE DECLARED AN EMER AND RETURNED FOR AN OVERWT LNDG AT MCO. LNDG WT OF 136300 LBS. LNDG WAS NORMAL.