An audible alarm would be working off the same systems as the master warning, so if none of these saftey systems were said to go off on the RAAF King Air then why would an audible alarm not fail as well.If no warnings went off in this accident then maybe there is a fault developing with the King Air pressurisation system. Maybe the recomendation should be to start doing a more complex 6 monthly check on pressurisation systems and there associated warning devices.. .It would be interesting to hear from any RFDS pilots to see if they have had any similar incidents being one of the longest King Air operators. <img border="0" title="" alt="[Roll Eyes]" src="rolleyes.gif" />