If your fixed length file dosn't have a standard fielddelimitor, you can't use split(), you wil have to supply the start position of each field in the record.

In the following code, the function: CrtFldArr()
returns an array of fields in the record based on starting position of all fields in the fixed record.
code:
Break On
$FieldStart = 1,11,51
; Change $FieldStart to fit your input file
 
; Loop thru file
$Rec = ReadLine(1)
$FieldArray = CrtFldArr($Rec,$FieldStart)
; Do something with the returned fields
; End Loop thru file
 
Function CrtFldArr($Rec,$FieldStart)
   Dim $Ret[0],$i,$UB,$L
   $UB = UBound($FieldStart)
   For $i = 0 To $UB
      ReDim Preserve $Ret[$i]
      If $i = $UB
         $Ret[$i] = SubStr($Rec,$FieldStart[$i])
      Else
         $L = $FieldStart[$i + 1] - $FieldStart[$i]
         $Ret[$i] = SubStr($Rec,$FieldStart[$i],$L)
      EndIf
   Next
   $CrtFldArr = $Ret
EndFunction
-Erik