Pilots' reaction to explosion missing from tape | theage.com.au
my exerpts from article are;
..........."Unfortunately, the standard two-hour recording, which works on an endless loop principle, did not contain the de-pressurisation event," senior ATSB investigator Neville Blyth told a media conference in Manila.
"The oldest part of the recording on the cockpit voice recorder commenced after the descent and diversion to Manila, so the event itself appears to have been overwritten."
He said the audio could yet be "very, very useful" - including in relation to examining airflow. "There is a surprisingly large amount of information that can be obtained from acoustic spectrum analysis, if indeed we have a recording of the event," Mr Blyth said.
In some of the previous explosive decompressions the analysis of the CVR could distinguish between a bomb (overpressure followed by outflow) and a pure fuselage rupture (outflow). Additional factors include reverberation (reflected waves off bulkheads) and structure borne dialation waves. Too bad in this case that the info is overwritten. I was surprised about the time frame that the CVR was running after the event.
Mr Blyth acknowledged that the "most likely explanation for the absence of the cylinder" was that it was blown through the fuselage.
I am never sure about news articles and whether they are paraphrasing what is said or whether they are actual quotes. But the quoted article above seems to leave open the possibility that the Oxygen tank might not have ruptured and simply tore loose out the hole afterwards.
