From Dozy, just above, commenting on the INVESTIGATION PROCESS:
"... I think Vette and Mahon's investigations were more in-depth and the conclusions more correct than those of Chippindale ... scrupulously honest ... The problem ... the information Chippindale had ... was tightly controlled by ANZ ... was only the material that ANZ wanted him to see. The only major fault I see in Chippindale's methodology was inviting Captain Gemmell to participate..."
Dozy -- NICE, there should be a forum for such critique of the mishap-"investigator", constructive additions to too-limited investigations.
[Maybe I'll go back over the years and tack these investigator-errs into an organized compilation: investigating-the-investigator, or expanding the focus of an investigation.]
This mishap- INVESTIGATION(s) [NZCAA & Royal Commission's] turned out much better than some others of that same year 1979: The Royal Commission PROCESS seems much better than the UNCHALLENGED product from the USA-system, where the USA's NTSB is legally the SOLE judge of their past investigative-product (never any critical oversight from any Royal Commission).
The NTSB might consider a PETITION from the French BEA (eg, ATR72 at Roselawn), but will mostly ignore any domestic-petition that contradicts the USA's big manufacturer (eg, the NTSB's endorsement of the "Boeing Scenario" in AAR81-8 while the direct evidence and the surviving crew told the Board otherwise). Boeing created data, analysis, simulator-runs, insisting that the NTSB agree that the direct evidence ranked lower than Boeing's created "evidence". [That investigation described in AAR81-8 was the longest most expensive investigation in the then history of the NTSB, & the B727 was then the best selling product of the USA's biggest exporter.]
http://www.pprune.org/safety-crm-qa-...-accident.html
Dozy -- thanks for those comments on the investigative-process: the USA's "independent" Safety Board concept, over the past forty years, seems mostly to produce an "investigative product" of lesser quality. Where as the public's option of the NZ- Royal Commission might force the investigator [NZCAA] toward a more complete, better quality product; & reduce subtle bias in evidence-rejection (eg, Chippendale's exclusion of Vette's HF-components).