Narrative:

All ground operations normal. WX, VFR conditions at mco. Departing runway 18L. Takeoff ground roll was normal up to about 10-15 KTS prior to V1. At this time, first officer instruments had an intermittent indication of full scale airspeed, altimeter rapidly winding up and vsi indicating climb condition. The instruments returned to match the captain's instruments after about 1-2 seconds. Captain and standby instruments agreed with each other and appeared accurate throughout flight. Normal rotation and climb out through gear up were accomplished. Passing about 1000 ft, first officer instruments again gave same erroneous indications as above for about 1-2 seconds. Continued with normal procedures of half rate, flaps up and climb power. We suspected a pitot static problem and were concerned about the aircraft wash that was completed the night before. Captain decided to return to mco for maintenance. Approximately 2000-3000 ft, the first officer instruments froze with the following indications: airspeed pegged at full scale, altimeter at 10000 ft, and vsi at 1000 ft climb. Additionally, FMA altitude window was blank and dfgc altitude selector window was blank. The instruments remained frozen until landing ground roll when they returned to normal. Captain flew a normal pattern for an ILS runway 18R and completed a normal landing. At the gate, maintenance could not find any problem with the aircraft. They accomplished a bite check on the cdc #2 and it checked normal. They still suspected a computer problem, so they replaced the cdc #2 anyway and checked the pitot static system for leaks (none found). Once repaired, we flew the aircraft uneventfully to lga. Supplemental information from acn 589680: after watching the ground crew's taping off all aircraft openings, the previous night in preparation for aircraft washing, I suspected that some of the static ports were still covered. We declared an emergency and returned for an overweight landing at mco. Landing weight of 136300 pounds. Landing was normal.

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Original NASA ASRS Text

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

Narrative: 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.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.