The ATSB supports safety recommendations the SA Coroner has made today that reinforce those by the ATSB, but disagrees with some of the Coroner's key conclusions.
The ATSB formally re-opened its investigation in November last year after possible significant new evidence about a potential manufacturing defect in the left engine crankshaft became available from the US engine manufacturer (Textron Lycoming)
- the ATSB has since re-tested the crankshaft, including using destructive testing open to non-Bureau witnesses and the input of external laboratories, and found no problems with the steel that could have led to it fracturing under normal operating conditions;
- in contrast to the Coroner's conclusion, this confirmed the ATSB report findings.
The ATSB does not agree with the SA Coroner that the pilot of VH-MZK would have allowed, ahead of any stressful situation, his right engine to overheat to the point of melting a hole in a piston and then be unlucky enough that a deep-seated long-term problem in the left engine crankshaft would have suddenly caused that engine to fail
- the ATSB continues to believe that the left engine failed first and then the right engine overheated when power was boosted in response, when seeking to reach Whyalla;
- as the ATSB told media when releasing its report on 19 December 2001, it is not appropriate to blame the young pilot in this scenario and the ATSB did not do so.
The ATSB report also did not criticise Whyalla Airlines for its fuel leaning settings in climb, finding that they were in accordance with the aircraft manufacturer's guidelines
- the ATSB continues (since October 2000) to urge industry to use conservative (rich) fuel climb settings in Piper Chieftains to minimise the possibility of engine damage.
The December 2001 ATSB investigation report was released after a major 18 month investigation and was based on the evidence available at that time
- there were no survivors or any aircraft flight data or cockpit voice recordings to assist the ATSB with the very complex investigation;
- the recommendations that the ATSB made in 2000 and 2001 to improve future safety have been widely regarded, including by the US Federal Aviation Administration.
The ATSB cooperated fully with the South Australian State Coroner's inquiry in the 18 months since the Bureau's report was released but found the inquest unduly adversarial
- parties seeking US civil damages money used the inquest to attack the ATSBs report into what are very complex issues, and this was supported by the Coroner's assistants;
- the ATSB has no financial or 'blame' agenda and is only interested in future safety;
- in hindsight any complex report can be improved and the ATSB's is no exception.
The Executive Director of the ATSB, Mr Kym Bills, has today written to the SA Coroner seeking any significant material that he may have relied upon that the ATSB has not seen. The Bureau will carefully review any new material provided before publicly releasing a supplementary report to close its re-opened investigation.