"Jaberoo" down (Mildura this time)

[jetjr]

Good work,

 

Further complicating issues may be 2200 vs 3300, as Dafyyd mentioned through bolt breakage and exh valve failure are complicated issues, fuel distribution and variable CHT and EGT could come into the equation and this differes on the two a fair bit

 

Also major revisions like hydraulic lifters, the early models with these sure sufferred more than older versions and im guessing the newer makes.

 

So model of engine, age and spec is important too, RAA should have much of this info too as serial numbers.

 

Im Trying to say the more this is drilled down into it may make the true cause of the problem be targetd without metallurgical investigation etcetc.

 

 

[turboplanner]

I also did the same 54 months reports on Rotax (912 class) on the second Excel page, post #306 which showed 7 forced landings, and an interesting trend on self maintenance.

 

 

[Dafydd Llewellyn]

I also did the same 54 months reports on Rotax (912 class) on the second Excel page, post #306 which showed 7 forced landings, and an interesting trend on self maintenance.

Ah, OK, found it - I'll do the same with it.

However, before anybody gets too excited over this wealth of information, consider what we DON'T know from it:

 

We don't know anything at all about the engines that did NOT fail.

 

We do not know the total fleet hours or the fleet hours by engine type.

 

We do not know anything about the TIS at which engines are being pulled for major maintenance, or what causes them to be pulled.

 

Without this information, one can only make guesses at the failure rate per flying hour.

 

Getting more specific, looking at the 17 through-bolt-related failures for Jabirus:

 

We don't know how many of these would have been prevented by timely application of the Jabiru Service Bulletins on the subject.

 

We don't know how many of them occurred in spite of timely application of the Jabiru Service Bulletins; or how many of those were caused by inept application of the Service Bulletins (which would show as failure shortly after the SB was implemented, presumably).

 

None of this is really getting into the difficult forensic stuff, so it's all within the capability of the RAA, if they wanted to.

 

There's nothing at all difficult about what Turbs has done, other than the tedium of picking it out of the magazines and putting it into the spreadsheet. Turbs has very effectively highlighted how easily RAA could at least get this far with even the inadequate data it has collected. GFA has an electronic means of airworthiness incident reporting in place; why not RAA? Once you have this, it's not rocket science to at least sort it into a data list, surely? And why not put that in the public domain?

 

 

[motzartmerv]

A lot of stuff goes un reported, there are several reasons for this, and to be honest the RAA in general doesnt have a ' reporting culture'.

 

I know its the rule etc, but dont put a lot of weight in this, I know many many operators that just dont bother.

 

If you report everything that goes wrong, then you can expect a please explain from the RAA as to why your having so many issues.

 

So your dammed if you do, dammed if you dont. Dont flame me over this, I report everything, and I also have been asked to explain the ' rash' of reports..

 

Its not very conducive of encouraging a reporting culture, and It interesting to see how it gets handled. I have posed the question to the RAA, 'are you asking the manufacturer to explain this rash aswel', or is it just me? Reckon I get a reasonable response? .......

 

 

[turboplanner]

RAA still does not have a Safety Management System, which forms the base on which you can and will report incidents, so it is wide open to get bounced some time.

 

When you have the SMS then comes the compliance and enforcement, which is usually done by volunteers in sporting activities.

 

If you write your SMS in such a way that reporting an incident absolves you from penalty, the reports will flow and the lessons be shared and the incidents be less.

 

It doesn't take an Einstein to know that an FTF reporting a rash of issues is an FTF which cares about safety - it may need help, but it doesn't need ignorant condemnation.

 

 

[Guest Andys@coffs]

......Issues such as loss of compression, causing engines to be withdrawn from service, are not covered by this analysis, as they do not appear in the data set....

Which is very much a shame, because if you do the maintenance as per the manual and test leakdowns you find issues in advance of catastrophic failure. In my case a leakdown of 40:80 saw me withdraw and major overhaul well before any failure, in fact the only issue I had was oil use was up and belly oil painting was significant....another 20-30hours and I'm sure their would have been a bang.

 

I did report the requirement to have major overhauls done to RAAus, but in this case, despite my angst it was fundamentally my fault in that I didn't use the aircraft often enough and didn't inhibit and it did corrode in the bore, pretty much as the manual said it would......

 

Andy

 

 

[Dafydd Llewellyn]

A lot of stuff goes un reported, there are several reasons for this, and to be honest the RAA in general doesnt have a ' reporting culture'.I know its the rule etc, but dont put a lot of weight in this, I know many many operators that just dont bother.

If you report everything that goes wrong, then you can expect a please explain from the RAA as to why your having so many issues.

 

So your dammed if you do, dammed if you dont. Dont flame me over this, I report everything, and I also have been asked to explain the ' rash' of reports..

 

Its not very conducive of encouraging a reporting culture, and It interesting to see how it gets handled. I have posed the question to the RAA, 'are you asking the manufacturer to explain this rash aswel', or is it just me? Reckon I get a reasonable response? .......

Well, that's a direct result of the CAO 95.55 exemption to CAR Part 4B

 

 

[Dafydd Llewellyn]

Andy, a lot of the non-reporting must happen because the operator concerned has a guilty conscience about it; whereas somebody who feels a genuine grievance is far more likely to report it. So to some degree the non-reporting may be offset by what amounts to an operator acknowledgement that it really wasn't an unprovoked occurrence. Not everybody is as honest about it as yourself.

 

One can't put numbers on this, of course; but in an arm-waving kind of way, one can make at least as reasonable a stab at the dimensions of the problem, as the "Jab Bashers" have pretended to do. Try this for size:

 

1. The data Turbs supplied covers the period March 2007 to March 2012, i.e. five years.

 

2. What's a reasonable guesstimate for the average annual utilisation? Let's say, for the purposes of the discussion, 40 hours per year for a private owner, 250 hours per year for a training organisation. If ten percent of the active fleet are used for training, that works out at 61 hours per year, on average.

 

3. What percentage of the fleet is grounded for want of a serviceable engine, or whatever? Let's say half. That brings the average utilisation down to around 30 hours per year.

 

4. How many Jabirus in the fleet? For 2012 it was about 930; I don't know the annual growth rate , but would 800 be a fair guess for the average over that five year interval?

 

If we accept all the above guesses, then the total utilisation would have been 30 x 800 x 5 = 120,000 hours. We have 40 reported "engine problem" occurrences; let's suppose there are an equal number of unreported occurrences of similar severity. That's 80 occurrences. The rate from those numbers is therefore 80 / 120,000 = 1 / 1500 - i.e. one per 1500 hours flying, or 1 in 1500 per flying hour.

 

That's STILL less than the benchmark probability of one in a thousand per flying hour, for an aircraft approaching the end of its "safe life" for structural fatigue.

 

Anybody can put their own numbers into this sort of estimate; but unless I'm way off the mark, that probability is nothing out of the ordinary.

 

On these sort of numbers, I'd be surprised if CASA got excited about it. They may use the RAA bleat as an excuse to push their own agenda, of course, assuming they have one.

 

 

[DrZoos]

What and where is the RAA bleat..i missed it

 

 

[Dafydd Llewellyn]

What and where is the RAA bleat..i missed it

See Post # 265 on this thread.

 

 

[M61A1]

RAA still does not have a Safety Management System, which forms the base on which you can and will report incidents, so it is wide open to get bounced some time.When you have the SMS then comes the compliance and enforcement, which is usually done by volunteers in sporting activities.

If you write your SMS in such a way that reporting an incident absolves you from penalty, the reports will flow and the lessons be shared and the incidents be less.

 

It doesn't take an Einstein to know that an FTF reporting a rash of issues is an FTF which cares about safety - it may need help, but it doesn't need ignorant condemnation.

Section 4.08 of the ops manual has been there for as long as I can recall. It lays down our procedure for reporting, and points out that there is no exemption for the CARs relating to reporting, so that comes under the CASA/ATSB umbrella. So, given that only AOCs require a Safety Management System (under CASA), why are we, as private pilots having to deal introducing an unnecessary SMS, while we have an Ops and Tech manual that defines what, and how we operate. The sole purpose of these manuals is safety.

 

 

[Oscar]

A lot of stuff goes un reported, there are several reasons for this, and to be honest the RAA in general doesnt have a ' reporting culture'.I know its the rule etc, but dont put a lot of weight in this, I know many many operators that just dont bother.

If you report everything that goes wrong, then you can expect a please explain from the RAA as to why your having so many issues.

 

So your dammed if you do, dammed if you dont. Dont flame me over this, I report everything, and I also have been asked to explain the ' rash' of reports..

 

Its not very conducive of encouraging a reporting culture, and It interesting to see how it gets handled. I have posed the question to the RAA, 'are you asking the manufacturer to explain this rash aswel', or is it just me? Reckon I get a reasonable response? .......

Merv, this is - and I am not questioning the accuracy of your statement that I bolded in the quote above - surely a serious matter?

 

Australians tend to think of 'dobbing in a mate' as a socially unpleasant action. I certainly share this attitude in general and I am sure that if I think about it there are numerous examples in my life where I have not reported something that perhaps should have been reported in the context of the possible consequences that perhaps didn't materialise due more to good luck than good management or intentions.

 

However, we have had on this site, more than a few discussions about the importance of drawing attention to unsafe flying habits and I believe that just about all of us here agree that it is in the best interests of both the individual and the organisation that patently unsafe flying behaviour be reported.

 

Is there any qualitative difference between reporting unsafe flying habits and reporting unsafe maintenance or incidents? The end result of either could quite possibly be death or serious injury.

 

Something that is a safety problem, or has caused an incident that is in the ambit of 'reportable' under 4.08 of the Ops. manual, might not in that particular case have resulted in anything serious BUT knowledge of it might well prevent a later occurrence that had a far worse outcome. From your comments, you recognise this and duly report, and that - surely - helps improve safety for all.

 

There is a time-honoured adage: 'if we don't learn the lessons of history, we are doomed to repeat it'. Pretty obviously, if the 'lessons' are not reported then how can people 'learn'?

 

 

[rick-p]

What is that supposed to mean Rick P, are you attempting to insult me?

David, if I wanted to name and shame you I would have said 'David' first. It was meant for the whole thread because things have become so damn boring with everyone trying to vi for who's got the best and most reliable pecker in the woods and can incite the most dissention amongst the forum users!

 

This whole argument is out of control with baiting, biting, bitching and on the part of some just shear nonsense.

 

Also extremely unproductive for all and sundry.

 

 

[DrZoos]

People need to stop taking the argument personally and just discuss alleged fact and opinions... If someone posts infavour of jabs great...if someone bags them just as great...its the reason and explanation that determines the value of each post..

 

Please, this is a great discussion allow it to continue and dont get emotional about it...if we all agree it would be horribly boring

 

 

[bexrbetter]

Please, this is a great discussion allow it to continue and dont get emotional about it...if we all agree it would be horribly boring

You almost got me, I almost clicked on the 'Agree' icon!

 

 

[motzartmerv]

I can understand why some don't bother reporting , I don't agree, but I still understand.

 

Same goes for reporting bad or unsafe flying. It's a very fine line between dobber and crusader in our culture.

 

I've written to the raa once about a pilot I believed was unsafe and under trained after flying with him.

 

I recommended he lose pax privelge pending an assesment. I was told an investigation was needed.. That the last I heard of it. I don't know what happened from there.

 

 

[David Isaac]

David, if I wanted to name and shame you I would have said 'David' first. It was meant for the whole thread because things have become so damn boring with everyone trying to vi for who's got the best and most reliable pecker in the woods and can incite the most dissention amongst the forum users!This whole argument is out of control with baiting, biting, bitching and on the part of some just shear nonsense.

Also extremely unproductive for all and sundry.

Sorry you feel that way Rick, pity you didn't say that with your first post, because what you posted was indecipherable. How any reasonable person is supposed to understand what that was supposed to mean is beyond me.

I am of the view that your reaction is hypersensitive, because there has been some excellent discussion in this thread. Why don't you go back and count the posts that you allege are " baiting, biting, bitching and nonsense" and compare the number you get with the productive posts.

 

Or is it more the case of what I alleged in my Post #264.

 

 

[Dafydd Llewellyn]

Here's my tabulation of Turb's data for the Rotax 912 series. It adds very little to his spreadsheet - but it's in Word, which may be more convenient for some readers. The info is just as wanting as for the Jab tabulation, and subject to the same limitations.

 

As you can see, there are no obvious systemic fault causes; the faults are essentially random, and as Turbs pointed out, mainly indicative of faulty maintenance.

 

The total number of occurrences was seven; the jab. occurrences for the same time interval numbered forty. Given an assumed percentage of the fleet double that of the Jabirus, and assuming a similar utilisation per aircraft (which may not be correct, but I have no better information), that would suggest that the Jabiru occurrence rate over this period was approximately (40/7) x 2 = 11.4 times that for the Rotax 912 series. The MTBF, for what that number may be worth, was not better for the Rotax than for the Jabiru.

 

So there is indeed some point in what Ian Bent is doing.

 

However, the failure probability for the Jab. engines is (as far as I can estimate, given the lack of data) still less than 1 in 1000 per flying hour; and three-quarters of the Jab rate is due to two identified causes, which are (in the CAMit mods, and for the through bolts, by the Jabiru Service Bulletins) arguably fixed (tho time will tell, of course) - so the real issue here is, I think, what the statistics do not show, which is the rate at which engines are being pulled out of service for major overhaul - i.e. the mean time between overhauls.

 

The CAMit mods will, I think, make a considerable improvement in the TBO - but again, that will only be proven in the light of experience.

 

So yes, the Rotax shows up as having a significant advantage over that time interval. Keeping the temperatures down in your Jab will pay dividends; and do pay attention to the manufacturer's Service Bulletins.

 

912 failure statistics.doc

 

912 failure statistics.doc

 

912 failure statistics.doc

[Powerin]

I went through the the RAAus register a couple years ago when it was available as a CSV file and put it on a spreadsheet. At that time the engine type was not shown, so I made some educated guesses and came up with the ratio of Jabiru engines to Rotax 912 to be about 8 to 7.

 

The on line RAAus register currently is not available as one file but does include engine types and models. It is only possible to view 100 entries at once which makes it difficult to quickly check the validity of a search. But a simple search of the register using the term "Jabiru" comes back with 1100 hits. This search includes 11 Jabiru airframes that do not have a Jabiru engine and 11 that are not recorded but would possibly be Jab engines...perhaps they are still being built.

 

A search for the term "912" gives 1407 hits. A quick browse through both those search results show them to be reasonably valid numbers I think.

 

So I believe the engine numbers on the RAAus register are:

 

Jabiru- 1078

 

Rotax 912 - 1407

 

Rotax 914 - 30

 

Edit: CASAs service difficulty reports are also available online and in yearly files. I am not sure if these are only VH registered aircraft? Reading through these also seems to show a trend for the afore mentioned specific Jabiru faults. Continental also seem to have specific faults whereas Lycoming is random like Rotax. Rotax has not appeared in the CASA SDRs in the past five years that I have looked at....I don't know if there is a statistical reason for this other than a lack of Rotax service difficulties. The above is just a general impression from browsing the SDRs and I haven't done any analysis.

 

 

[Dafydd Llewellyn]

OK, thanks - well, as anybody can see, that changes the relative occurrence rates, from 11.4 to (40/7) x (1407/1078) = 7.5 - i.e. over the period covered by the data, the Jabiru engines had 7.5 times the occurrence rate for the Rotax 912 series.

 

I emphasize again, that the lack of accurate data and the unknowns such as what percentage of occurrences are reported, makes all these figures decidedly "rubbery"; however, they do, I think, give a tolerable relative notion of the rates as they existed over that period (2007 ~ 2012).

 

 

[rick-p]

Sorry you feel that way Rick, pity you didn't say that with your first post, because what you posted was indecipherable. How any reasonable person is supposed to understand what that was supposed to mean is beyond me.I am of the view that your reaction is hypersensitive, because there has been some excellent discussion in this thread. Why don't you go back and count the posts that you allege are " baiting, biting, bitching and nonsense" and compare the number you get with the productive posts.

 

Or is it more the case of what I alleged in my Post #264.

I have already done that David, not only in this post but also other related posts in respect of engine reporting matters and my observations still remain the same.

 

There are some very smart informative people who use these forums but there are also others that need to get a life outside the internet.

 

It's called cyber bullying if you haven't heard.

 

I'm hyper nothing just concerned that their are a lot using these forums, making statements that are absolutely without foundation or even in some cases no common sense.

 

I come and go from time to time but things just don't seem to change.

 

I enjoy the forums but get annoyed when I see so much in the engine reporting threads or accidents and incidents that is totally inappropriate and unproductive to the user, the manufacturer and even the interested parties and more likely than not most frightening to the newbe of the sport.

 

 

[rick-p]

As I said David I wasn't naming you, you have for the most part in your posts been constructive, case in point is your post 264.

 

Maybe you are being a little hypersensitive yourself.

 

Have a great day.

 

 

[David Isaac]

Thanks for your explanation Rick.

 

I doubt I am hypersensitive in the sense of an engine bias as I don't own either type of engine in the debate. I own a good old 1930s Gipsy Major and they have known problems. But at least they are known and can be managed by a top overhaul every 400hrs or so.

 

But I do like good constructive discussion on these issues. Usually the thread will self moderate and come good as it has in this case.

 

Unfortunately we will always get the good with the not so good at times in any forum of this nature.

 

Cheers.

 

 

[Stewy]

Just thought that we may be interested in the cause of this engine out.

 

It was an exhaust valve that broke.

 

So fits the bill of other failures, I think that there was excessive clearance in the valve guide.

 

I believe Jab supplied a top end overhaul kit approx 12 months ago but don't know who preformed the work at this time.

 

Regards

 

Stewy

 

 

[Dafydd Llewellyn]

Ha! Yes, that fits the pattern as Ian Bent explained it. Thanks. It's not necessarily a result of poor installation practice; excessive guide clearance can also result from insufficient oil flow in the spring pocket area inside the rocker box (which cools the exhaust valve guide).