AN ATR42 FLC AT TVC DID NOT UNDERSTAND BRAKING RPT ISSUED BY THE TWR.

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BEFORE DEPARTING ORD FOR TVC; OUR FIELD RPT FOR TVC SHOWED BRAKING ACTION FOR RWY 28 AS '118 104 86 MU.' IN CHKING OUR FLT MANUAL; WE COULD FIND NO CHART (MU; SAAB; TAPLEY; ETC) THAT WOULD CORRESPOND TO NUMBERS OVER 100. WE CALLED OUR COMPANY DISPATCH AND THEY ALSO COULD NOT FIND A CHART THAT RELATED TO '118 104 86' NUMBERS. THE DISPATCHER CALLED THE TVC TWR AND ASKED THEM FOR A BRAKING ACTION RPT; WHICH WAS OBTAINED FROM ANOTHER ACFT; AND PASSED ON TO US BEFORE WE DEPARTED ORD FOR TVC. ARRIVING IN THE TVC AREA; WE ASKED THE TVC TWR FOR A BRAKING ACTION UPDATE; AND THEY GAVE US NUMBERS OF '108; 104; 86' AGAIN. WE ASKED THEM WHAT THOSE NUMBERS CORRESPONDED TO (IE; GOOD/FAIR/POOR/NIL BRAKING) AND THEY SAID THEY DID NOT KNOW AS THE ARPT AUTH AT TVC ONLY GAVE THEM NUMBERS BUT NO CONVERSION CHART. THIS SEEMS LIKE A VERY DANGEROUS SIT BY TVC AS THEY HAVE A BRAKING CONDITION DATA SYS THAT FLCS; AIRLINE DISPATCHERS AND EVEN ATC CANNOT RELATE TO. TVC HAS SOME VERY NASTY WINTER WX (VERY CLOSE TO LAKE MICHIGAN WITH LOTS OF LAKE EFFECT SNOW) SO BRAKING ACTION DATA IS VERY MUCH NEEDED.