DT CX,#523/524 AIR LEAK TEST FAILED,1.2B ~~~~~ DT CX,#523/524 AIR LEAK TEST FAILED,1.2B     #3524 ACU found leaking at exhaust port.Isolate PBIC,suspect PBSV faulty.Swap PBSV to #1524 fault did not transfer.Further check bogie 1 slow to release.Replaced ACU leaking stopped.Air leak test 0.4b/5min after replacement of ACU. #3524-ACU:- Not: 2425631 raise to CSC. Done by Arthur Sam. 11/10/22