I've just read your latest release.
You mention the Cockpit Voice Recorder not having any data.........for clarity, they weren't fitted in those days....wasn't mandated in the US until 1967.
There was a flight recorder (FDR in modern terminology) that only records data, and as you mention it had no recoverable information.
Last edited by booke23; 2nd Jan 2018 at 23:08.