RPTR FLIES INTO ICING CONDITIONS THAT EXCEED THE ACFT DE- ICE CAPABILITY.

Narrative

THE INTENDED FLT WAS PROPOSED FROM ROC TO TEB: DEPARTING ROC AT XO20 LCL TIME ON FEB/XX/95. THE ACFT WAS A PA-23- 250 (PIPER AZTEC APPROX 300 LBS UNDER GROSS WT. THE PLT RECEIVED A STANDARD WX BRIEFING FROM BUFFALO FSS AT XA30 LCL AND RECEIVED AN UPDATE AT XO00 LCL. BRIEFERS RPTED IFR AT ROC AND ALONG THE PROPOSED RTE WITH VFR CONDITIONS PREVAILING TEB. LIGHT TO MODERATE ICING CONDITIONS WERE FORECASTED ALONG THE RTE FROM THE SURFACE TO 16000 FT AGL. THE AZTEC IN QUESTION IS EQUIPPED WITH FULL DEVICE PROTECTION AND 3 MONTH OLD DE-ICING BOOTS. THE PLT DEPARTED ROC AT X020 LCL AND WAS ADVISED BY ROC TWR OF 'SIGNIFICANT' WX 7 MI S OF THE ARPT AND TO MAKE AN IMMEDIATE L TURN TO HDG 190 DEG. THE PLT INITIATED THE TURN AND CONTINUED THE CLB TO 7000 FT. ROC TWR ADVISED THAT THE PLT WAS CLR OF THE WX AND HANDED OVER TO ROC DEP. UPON CLBING THROUGH 2000 FT MSL THE PLT INSPECTED THE WING AND TEMP PROBE NOTICING A SIGNIFICANT BUILD UP OF MIXED ICE OF ABOUT 1/4-1/2 INCH. THE PLT ACTIVATED HIS SURFACE DE-ICE EQUIP (PITOT-HEAT; WINDSHIELD; AND PROP HEAT WERE ON AT THE TKOF ROLL); WHICH CLEANED THE WING. THROUGH 4000 FT THE BUILDUP WAS ONCE AGAIN BECOMING SIGNIFICANT AND THE PLT ASKED ROC DEP IF THERE WERE ANY TOPS RPTS. DEP ASKED A C310 IN THE AREA WHAT THE TOPS WERE AND THE C310 RPTED 8000 FT MSL. THE AZTEC REQUESTED A CLB TO 9000 FT MSL. ROC DEP SAID TO MAINTAIN 7000 FT MSL. THE PLT ACTIVATED THE BOOTS AGAIN WHICH PARTIALLY CLEANED THE WING. UPON REACHING 6300 FT MSL THE AZTEC PLT COULD NO LONGER MAINTAIN ALT AND REQUESTED A DIVERSION WITH ROC TO THE NEAREST SUITABLE ARPT. FINGERLAKE REGIONAL WAS OPEN AND ROC GAVE A VECTOR OF 100 DEGS AND A DSCNT TO 3000 FT MSL. UPON REACHING 3000 FT MSL VFR CONDITIONS WERE ENCOUNTERED AND THE AZTEC PLT REQUESTED FURTHER DIVERSION TO SYRACUSE (SYR); ONCE HANDED OVER TO SYR APCH THE PLT ACCOMPLISHED A SAFE LNDG. THE AZTEC PLT LEARNED THAT WHEN WX CONDITIONS ARE QUESTIONABLE ALTERNATE PLANS MUST BE MADE: POSSIBLY PUTTING THE FREIGHT ON A TRUCK.