Give this a shot:

Sub test()
Cells.AutoFilter field:=1, Criteria1:="a"
Cells.SpecialCells(xlCellTypeVisible).Copy _
Destination:=Worksheets("Sheet2").Range("A4")
Application.CutCopyMode = False
Cells.AutoFilter 'turn off filter
Worksheets("Sheet2").Columns("A:B").Delete 'since we only want
column(c) values
End Sub