Just FYI, the recently released
CVR report from USAir 1529 notes the CVR pinger did not activate as it should have when shorted by water.
The underwater locator beacon (ULB Dukane Model DK100, s/n DM1661, battery expiration date October, 2009) did not function when tested. After shorting the center electrode to the case, no sound was detected using a Dukane Ultrasonic Test Set Model 42A12. The beacon was also tested using a Dukane Test Set Model TS100, which indicated “Open Probe/Batt.”
Hopefully not a problem with those on AF447.