Media Release
2009/15: Oxygen bottle failure and depressurisation accident still under rigorous scrutiny
17 November 2009
The Australian Transport Safety Bureau is continuing its
rigorous and comprehensive examination of the circumstances
surrounding the failure of an oxygen cylinder that led to the
depressurisation of a Boeing 747 on a flight from Hong Kong to
Melbourne in July last year.
The ATSB's second interim factual report on this accident,
released today, indicates that to date there is no evidence of
systemic safety problems with oxygen bottles of the type involved
in the accident. Various tests have not been able to replicate the
cylinder failure that initiated the accident.
The report provides details of the wide-ranging and ongoing
technical examination of five oxygen cylinders obtained by the ATSB
from the same manufacturing lot as the failed cylinder. The
original cylinder was lost in the South China Sea in the course of
the accident.
Analysis of the factual information and findings as to the
factors that contributed to the accident remain the subject of
ongoing work. Details will be included in the final report of the
investigation.
To date, all pressure tests of the cylinders met or exceeded the
relevant safety specifications, with recorded rupture pressures
being over twice the maximum working pressure of the cylinders.
Other work is being carried out to determine the minimum size of
mechanical flaws that could result in cylinder failure in service.
The ongoing ATSB investigation will supplement that work with a
program of rupture tests on cylinders that have had various sized
'artificial' flaws machined into the shell.
The ATSB expects to conclude the data gathering and analysis
aspects of the investigation in early 2010, with a final report to
follow.
Media Contact: 1800 020 616
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