qolbinau

is The problem with this interpretation is that 2x a small number is still a small number. I think it is more useful to look at it in real-world terms. For every 10,000 flight hours, you can expect approximately 1 Rotax incident/serious incident and 2 Jabiru incidents/serious incidents. Yes, technically that is twice as many Jabiru incidents. However, both numbers are still small. With such small numbers (but consistent differences across years), for me they suggest that Rotax is producing a more reliable product - and from all I've read about Jabiru engine issues and the manufacturer's response to said issues, probably better customer service. But I'm not sure this data suggests that the Jabiru engines are so inherently unsafe that a passenger should have to sign a waiver to fly in one. It seems like an ACCC-type body rather than CASA should be involved here (a poster in another thread claimed that the only reason Jabiru can get away from the ACCC is because the goods are >$40,000).

I don't know about the history of that research. However, while such an analogy might help me accept that there can and are mistakes in research, the only helpful way to suggest that the ATSB data are inaccurate would be to provide reasons (e.g. unrepresentative sample). Is there any feature of the ATSB investigation that stands out to you that could suggest its results are inaccurate?

Sorry I know we're going in circles but CASA are intervening (according to their words) because of the risk of *engine failures*, and the ATSB data show that *engine failures* are not substantially different from a 'reliable' engine. The reliability issues of Jabiru engines may cause engine failures, but this outcome does not appear to be much different from a 'reliable' engine. From what we've seen, CASA's data is junk (no base-rate, small sample, not looking into the actual cause of the engine failures when the information was available). If CASA won't listen to this, this is actually the problem here. I value my safety and recognise that people have been complaining for years that Jabiru engines have reliability issues. This is hard to ignore. But it's also hard to ignore that when the ATSB do what seems like a thorough investigation, with years' of data and comparisons between engine types and registration types, there does not seem to be a clear outcome (in terms of engine failures) of these reliability issues. CASA actually say that data from the ATSB has informed their decision, which is also puzzling. It seems like they've gone about the process all wrong, and given the potentially very negative economic effects of this decision on various stakeholders, you would think they would have been gone about it in a better way. They've apparently had years to conduct a thorough investigation.

I'd prefer to sit on my computer and complain about it here to no one that has any decision making power, haha.

Am concerned at CASA's actions after reading this: http://proaviation.com.au/2014/11/28/indecent-haste/

Numbers are so important. Humans are subject to many cognitive biases, and the numbers are the only way to objectively know whether this is a real issue or not. If the ATSB statistics are accurate they provide evidence that Jabiru engines, while slightly less reliable than Rotax engines, do not have a high failure rate or a failure rate that is substantially greater than Rotax engines. If the statistics are accurate, it would suggest that if people think Jabiru engine failures are substantially more common than Rotax failures it is because there is an unrepresentative group of people sharing their experience using Jabiru engines (e.g., on this forum). This does not change the fact that there may be systematic manufacturing or design issues in Jabiru engines that cause maintenance issues or engine failures. However, if the ATSB statistics are correct then the outcome of these issues is not such that it results in engine failures substantially higher than Rotax engines. If this outcome is the criterion that CASA have decided to implement limitations on Jabiru engines the ATSB evidence does not support it. If CASA have evidence that is contrary to the ATSB I think they should provide it to be subject to peer review because their decision to implement this instrument will have an economic impact on Jabiru, business using Jabiru aircraft and the value of Jabiru aircraft. Ultimately, I am a risk-averse person and if I had evidence to suggest that Jabiru engines were not safe I do want to know ASAP. So far, there has been little hard evidence to support the claim. It's 2015 and according to Back to the Future we should have hover boards. I'd settle for evidence-based decision making.

The third option could be that they have misinterpreted statistics, or that the data are unrepresentative (as RAA have claimed). Where are the RAA figures?

The ATSB data indicate in my opinion that while Jabiru engines seem slightly less reliable than Rotax engines, reported incidents are low for both and there are only marginal differences in reported incidents. Thus, there does not seem to be a massive cause for concern about the safety of Jabiru engines based on this data. Does the data CASA is using to make its decision RE: Jabiru differ from the ATSB data? 45 engine failures (or whatever it is) is meaningless without any baseline or comparison statistics. Apologies if this discussion has already been had.

Apologies if this was posted recently, this thread is now becoming a monster so it's difficult to find things. But where can I access this data?

So if I interpret the ATSB statistics correctly, for every 10,000 flying hours there is approximately 1 extra RA-AUS Jabiru aircraft involved in an incident, serious incident or accident than an RA-AUS Rotax aircraft, or 1.3 extra compared to VH aircraft? Is this a trivial difference? With such little variation I would expect such differences would exist within each of the categories if you were to cut the data by more variables. I'm not sure if these differences warrant CASA's actions. Is the raw data publicly available?