It's also interesting and slightly disturbing that the consultation draft published doesn't list any engine types, model numbers or failure modes.

In my opinion, that's pretty poor professionalism on CASA's part. Why has the failure rate on an unspecified series of engine models suddenly become "an urgent safety risk"?

It would be easy to construe this as a commercial vendetta on someones part rather than a valid safety action.

Witness our government, for instance.:{

Absolutely Andy. How about some serial numbers, 4 or 6 cylinders, thru bolt compliance, etc. Nothing at all from them as yet.

Would you care to elaborate on that?

Formation of CO2 releases more than 3x the energy of CO.

My high school chemistry calculations (admittedly with 25+ years of rust) suggest that 10% excess fuel reduces the energy (heat) released by about 3%.

You get more molecules and hence more pressure at the same temperature, or the same pressure at a lower temperature.

Andy RR, I think that you will find CASA have had a couple of Audits of the Bundaberg factory where the topic was raised.

Also worth a look at the Jabiru Facebook page to see the owner reaction for and against the CASA proposal.

Ndegi, that may be true, but the CASA proposal makes no concrete case for the action. It's all hearsay and anecdote and, like I said, no data, serial numbers, model numbers or anything.

All engines have their weak points which need to be managed, but CASA wouldn't dare put blanket restrictions on "Lycoming engines" or "Continental engines" without specifying models, build dates, specs, installations or some other form of identification. Why is it OK to do this to a local manufacturer?

Even if Rod is being blind or belligerent, it's not CASA's job to "teach him a lesson" by wielding a big regulatory stick without just cause.

It's still just a proposal. Perhaps if the manufacturer supplies relevant data to limit the action to certain models or serial numbers CASA will change the proposal.

From today's RAAus email:

That makes Jabiru 0.67 per thousand hours, Rotax 0.22 and others 0.39.

Jabs way in front, if the stats are complete (which they may not be, based on track record). Even if they aren't, it's a wide margin.

I think you used landings for Rotax and hours for Jabiru. Rotax should be 0.22.

I make it Jabiru 0.67 per thousand hours, Rotax 0.22 and others 0.39.

Jabiru 3 times more likely to fail than Rotax.

Jabiru almost twice as likely to fail as the "others".

Enough reason to take action I suppose but I wonder why these stats are only now coming out. Why haven't RAAus (or CASA) advised us of this before. If they had then maybe market forces would have forced Jabiru to take action.

Indeed - fixed, thanks!

are rotax's more likely to be in installations where engine failures are shall we say less likely to be reported?

It's interesting data, but not really very enlightening.

Rotax = 447, 582, 912A/F/S/iS/UL/ULS 914F/UL and probably other variants

Jabiru = 2200 and 3300

Others = ?

Of course installation plays a big part in reliability too, so how many variations do all these account for?

Looking at the data from flight hours/landing perspective, you have 0.45hrs for Jabiru, 0.49hrs for Rotax and 0.50hrs as a fleet average, so clearly the use profile for Jabirus are different from Rotaxes and just what is it that's bumping the fleet average beyond even that...?

The data might be enough to trigger an investigation, but enough to destroy a company's reputation in public by regulatory sabre rattling?

There's certainly a case for more information required before proposing a case for regulatory action. And this proposed action? Just what comment should the public make without any concrete data or information?

waren9, are you suggesting Rotax owners are more dishonest than Jabiru owners?

I don't know about 'Dishonest' but I thought with the 2 stroke engines failures were more or less ops normal. I know of a couple that I'd bet good money never landed on any report.

It may just be all over after today's meeting with CASA.

There is work to be done and it's possible it may never come to fruition.

Rutan around, some at CASA seem to think a Jabiru engine failure is "ops normal".

Didn't Lee Ungerman work for RAAus? This issue hasn't suddenly arisen. Where was he then and what was he doing?

I would not put my wife in kids in an aircraft with a Jab engine, even with me driving it. Sad to see this happen to an Australian aircraft manufacture. In this case I believe CASA do have a legitimate reason to think about placing restrictions on the engines until the manufacture can come up with a suitable fix, which I doubt will happen unfortunately. Forget the stats, there is way to much evidence to convince me that the engines are unreliable, and I'm certain that there is a heap more engine malfunction events that haven't been reported.

andrewr, answers inserted in red.