Some seating sections at HBF Park in Perth have rows labelled AA, BB, and so on, alphabetically.
The first row of each seating section is row A, and continues backwards to row Z. The rows then continue in double letters, with row AA being the row behind row Z.
i.e., row AA is the 27th row from the front of the section, so the double-lettered rows are towards the back of each section.