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CASA - Draft Proposal for Jabiru Aircraft

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I used to have a reward on offer for the best take on "bogey", "bogey-up-your-nose", "bogle" .... etc etc. The world ran out of new ones sometime in the 1960's. I was in my teens ... :-)

No need to put me in your sights, I'm not the bogey here ....

 

 

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12 vs 40, Wouldnt that bring numbers down around the numbers listed for Rotax?

 

Right or wrong this would take the wind out of CASA claim?

 

 

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I think the blanket situation which Jabiru aircraft owners face at the present time where no specific defect has been identified

Through-bolt failure, exhaust valve sticking for which Jabiru themselves have released a bandaid (larger vavle reliefs in the pistons), heads pulling in requiring valve lash checking every 25 hours, head sealing leakage, cylinder barrel and head cracking, flywheel bolt failure and inconsistent overheating.

 

There, someone, for the very first time, has finally mentioned the issues.

 

 

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It is still not a clear situation. You need to know which of those YOU mention are common and which are not very common..

 

The head cracks were found to not cause any problem in the situation which was the subject of Darren's original AD. There may be other instances of more serious cracking in some engines but that is not common . ( Probably no more so that the Cont 0-200).. Your post only muddies the water. Bex Nev

 

 

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That is true, obviously unless EVERY Australian has both arms. I have discounted the likelihood of SOME having more than two in making my claim.

 

With the Jabiru situation for instance one should remove all stats that don't directly implicate the motor being at fault. ( Like icing Where not operated correctly fuel exhaustion/contamination, not enough oil.

 

Many of the cylinder problems were due to a problem of the radius and being distorted.

 

One could reasonably assume there will be cases of fitting the wrong circlip in the piston, when there are now 2 two different ones and a problem with faulty ones as well.

 

I found the circlips supplied with genuine Rotax TWO STROKE 582 pistons were too soft to install without them distorting and being a loose fit in the groove. A lot of this happens and often it is only the watchfull (experienced ) fitter who will notice and avoid a certain engine failure in the future. Nev

 

 

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True to a point nev. On the same argument, the same human mistakes should keep the other makes failure rate numbers just as high ?

 

At least proportionately hight due to the larger number of units in service? While stats can lie, they can also be pretty damming. Any "variable" with half the numbers, but twice the event count, needs an explanation.

 

 

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Alf refers to "our type of flying not GA or commercial". My ex-GA friends and I are flying exactly as we always have, but RAAus. Flying behinds a Rotax engine in a modern composite aircraft is no different, in any respect, from GA flying. We do our hour or so every weekend, a trip when we choose, and go to all the same places over the same routes that we might have flown GA in years past. There is nothing wrong with other forms of flying, but it should be borne in mind that most Rotax and (I expect) Jabiru flyers are not rag and tube experimenters but people who expect a GA style experience and reliability. Sure all engines can stop, but the GA experience is that something has gone very wrong when that happens. It is a thing most pilots will never experience, and those who experience it once can reasonably expect they will never experience it again.

 

 

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Your post only muddies the water. Bex Nev

No, my post is factual and verifiable over many, many years of incidents. Cracks in the head pertaining to safe operation or not doesn't change that people don't want to see them there at all, not confidence inspiring.

 

Ironically I posted it, i.e. facts, based on your statistics quip.

 

 

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Even the largest Radials have allowable cracks and fin loss on heads and cylinders. You mention a large number of alleged "FAULTS" none too specifically , which brought forth my comment which you quote. Why do use words like "quip". It isn't warranted in a sensible discussion. Nev

 

 

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Bex, just more repeated old info, bit surprising from you. Anyone can write a historical hit list of problems

 

Ive never heard of a cylinder crack, head cracks has been dispelled, who cares about confidence, the proposed action is about safety and these dont impact that.

 

Head recession is related to over heating and largely gone with new heads, tappet adjustments are ONLY on old more reliable versions. Not sure how you knock that design

 

Circlips and through bolt nuts, known issue and now documented, from now on they are maintiner error

 

So that leaves, as Jabiru and CASA have mentioned

 

Breaking theough bolts, well theres 10 or more opinions on the cause here and not clear fix, lots trying though. Bigger bolts, harmonics, fuel, bad bolts, fretting, loctite, wrong nuts too short etc etc.

 

Flywheel bolts are an issue and needs fix, also varied ideas on cause, dowels nd larger bolts havent fixed it and they were sound ideas too

 

Valve guides and other isues are a problem and flycut pistons might prevent this being a stoppage so why criticise that

 

Im never going to say things dont need work but criticisim for the sake of it doesnt help anyone

 

 

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Alf refers to "our type of flying not GA or commercial". My ex-GA friends and I are flying exactly as we always have, but RAAus. Flying behinds a Rotax engine in a modern composite aircraft is no different, in any respect, from GA flying. We do our hour or so every weekend, a trip when we choose, and go to all the same places over the same routes that we might have flown GA in years past. There is nothing wrong with other forms of flying, but it should be borne in mind that most Rotax and (I expect) Jabiru flyers are not rag and tube experimenters but people who expect a GA style experience and reliability. Sure all engines can stop, but the GA experience is that something has gone very wrong when that happens. It is a thing most pilots will never experience, and those who experience it once can reasonably expect they will never experience it again.

pmccarthy,

 

I probably should have explained my meaning a bit more thorough, yes we fly similar performance aircraft to a warrior or 172 but we don't fly at night (or we shouldn't), most of us don't fly in bad weather or under IFR rules like GA ect, we don't fly twins which some of after an engine failure won't stay in the air.

 

All I was getting at is compared to GA we don't seem to have the number of fatality's after engine failure compared to GA.

 

We seem to kill more from being stupid.

 

Alf

 

 

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Elsewhere is has been discussed, CASA are prepared, and theres precedent, that upon the disappearance of LSA cert holder, they will approve other parts suppliers.

Jetjr I asked if you could provide info re this precedent? I am interested to know what it was.

 

 

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How do flycut pistons stop valves failing?

 

Were they previously hitting the piston?

 

 

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Alf. ALL modern twins not only stay in the air with one engine out, they make the minimum climb gradient in the segment after takeoff. Plus a few other like go round on one engine This is assuming you fly the plane to the parameters required, which can be pretty critical. Nev

 

 

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True, although that was a bit of a "rush of blood to the head" thing. Me and the boys at YCAB have the world's only two Rotaxified J160's. There are unlikely to ever be any more. It goes fine, but for the $, time and stress involved I should have just flogged it off and bought a Tecnam or whatever.

I gussied up the paint job while I was at it. Not that this has anything to do with the thread ...

There are more than two Ian

 

 

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Sure all engines can stop, but the GA experience is that something has gone very wrong when that happens. It is a thing most pilots will never experience, and those who experience it once can reasonably expect they will never experience it again.

I've only had one engine failure and that was GA (luckily in a twin). I don't share your optimism that will never happen again, but that's life.

 

 

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Alf. ALL modern twins not only stay in the air with one engine out, they make the minimum climb gradient in the segment after takeoff. Plus a few other like go round on one engine This is assuming you fly the plane to the parameters required, which can be pretty critical. Nev

Depends what you define as "modern" and under what rules you're operating.

 

If you're < 5700kg in private operations there's no requirement to make any climb gradient in a twin, and indeed in a C310 or Duchess (among others) there's not a hope in hell you'll make a 2nd segment climb gradient with a moderate load on board.

 

In the Caribou in PNG we used to brief where we'd aim to crash after takeoff in the event of an engine failure, the only requirement being 100 ft/min rate of climb in the clean configuration, with no chance of climbing away if there wasn't time to retract everything!

 

Even an IFR charter twin (<5700kg) only needs to make 1% under CAO 20.7.4, and that's fully clean with the inoperative engine feathered.

 

It's even possible to be "2nd segment limited" in some passenger jets, however the performance data prevents you loading it to the extent that you can't make that gradient with an engine out.

 

 

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Through-bolt failure, exhaust valve sticking for which Jabiru themselves have released a bandaid (larger vavle reliefs in the pistons), heads pulling in requiring valve lash checking every 25 hours, head sealing leakage, cylinder barrel and head cracking, flywheel bolt failure and inconsistent overheating.

There, someone, for the very first time, has finally mentioned the issues.

All of the issues you have mentioned are correct over the history of the 2200/3300 series of engines. However, some of the problems you have raised may no longer an issue as they have been rectified over time or the affected engines are no longer in service. You quote "larger" valve relief.........not larger but either valve relief machined into the piston crown or not. I have been involved with the Jabiru product since before the intoduction of the 2200/3300 series engine having my first flights in a 1600 powered version. I am an L2 and have ben trained by the Jabiru factory and Wayne Johns in SA on Jabiru engine rebuilds so I have some experience. The current prevalent issues are through bolt failure/crankcase fretting and valves sticking in guides. The piston valve relief might be a "bandaid" fix but I can tell you that I'm a lot happier flying with one of these engines knowing a stuck valve will not cause a catostrophic engine failure. I also read a few posts citing engine overheating problems. This has not been an issue since the introduction of the fine fin series of heads some years back. So, during the evolution of the engine the issues have changed. My feeling is CASA will be targeting the current series of production engines and not ones made ten years ago with some of the problems you have raised in your post.

 

 

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How do flycut pistons stop valves failing?Were they previously hitting the piston?

Yes a stuck valve will hit the piston. (Not one with valve relief)

 

 

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Dutch r, I haven't operated to "private" rules in M/E. I have always operated to "theoretically" being able to fly on one, weights. Earlier aircraft like DH Dragonfly and Miles Gemini were never required.

 

If you fly a twin (or more) at a weight that won't fly engine out, you have an aircraft that has twice the chance of having a motor bring you to grief, plus the possibility of control problems thrown in if you don't understand assymetrical thrust and Vmc (a)& (g). Nev

 

 

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