CVR & FDR both have water activated acoustic beacons. Unfortunately, while robust they can be damaged and fail to work.
They should get 20 days at least out of the pinger batteries but tree is some deep water out there!
I think we have at least 4 sets of friends due to fly Air Asia in the next couple of months.
I have always found them to be a good airline with a young fleet of aircraft.
No consolation o the families of the lost though.

