AN S80 PIC RPT WHEREIN HE QUESTIONS THE VALIDITY OF THE ACR'S INTERP OF THE MEL FOR DISPATCHING ANY ACFT VERSUS AN S80 WITH ENG AIR ANTI-ICE NOT OPERATING; SUBJECT TO 'NO ICING CONDITIONS FORECAST' ENRTE. MCI; MO.

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DISPATCHED WITH ANTI-ICE SYS INOP. DISCUSSION WITH DISPATCH INDICATED NO ICING CONDITIONS ENRTE. I ASKED ABOUT HIGH CLOUDS ABOVE THE FREEZING LEVEL AND WAS TOLD ONLY CONCERN WERE CLOUDS OVER DFW; BUT NO PROBS DUE TO WARM TEMPS. HOWEVER; ON CLBOUT FROM MCI; ONLY WITH DIFFICULTY WERE WE ABLE TO REMAIN CLR OF CLOUDS WITH RAM AIR TEMP AT OR BELOW 6 DEGS C. ALSO DURING INITIAL CRUISE; THERE WERE LAYERS OF CIRRUS THAT ALTHOUGH THIN ENOUGH THAT ANTI-ICE WAS NOT REQUIRED; THERE WAS NO WAY FOR ME TO KNOW CONDITIONS WOULD NOT CHANGE FOR THE WORSE. IN RETROSPECT; WE SHOULD HAVE BEEN FLT PLANNED AT A LOWER FLT LEVEL (FL180-FL230) WITH WARMER TEMPS. UPON LNDG; I DISCUSSED THIS WITH ON-DUTY DISPATCHER. HIS QUESTION WAS 'WHERE DID WE ENCOUNTER ICE?' I SEE A DIFFERENCE OF FORECAST ICING CONDITIONS; USED BY DISPATCH; AND THE DEFINITION OF ICING CONDITIONS IN OPS MANUAL VOLUME 1 FOR THE MD80. FLYING IN CIRRUS AT FL350 REQUIRES THE USE OF ANTI-ICE ON AN MD80; BUT AS I RECALL; DOES NOT FOR SOME OTHER MODEL ACFT. IS DISPATCH AWARE OF THIS? IT WOULD AFFECT DISPATCHING ACFT WITH ANTI-ICE INOP.