Henry Ching writes:
There have been a number of postings recently on the crash of the CPA plane on Mount Butler in 1949 and air hostess Olive Batley who lost her life in that crash. There was another and perhaps more dramatic crash involving a plane owned by CPA which occurred in 1948 which may be of interest. The plane was a Catalina and was on its way to Macau from HK. It crashed into the Pearl River estuary about ten miles from Macau as the result of an unsuccessful hijacking attempt. 25 of the 26 people on board lost their lives – the survivor was one of the hijackers. He spent some years in prison awaiting trial, but he was never convicted as there was apparently some doubt as to jurisdiction. The air hostess was 21 year old Delca de Costa. Not much seems to be known about her, but probably a member of the local Portuguese community or from Macau. Her body was never recovered.
Wikipedia has additional information about this incident.