ATSB report into light aircraft engine failures

[jetjr]

Easy to say Greybeard,

 

Owners have lost large sums of money based on these numbers and their accuracy or more importantly the conclusions drawn matter a lot to them

 

If Jabiru cant continue then its a disaster for owners and RAA as a whole. Dont underestimate how serious this all is.

 

Just a bad year for Rotax failures and accidents - and they are having one - could see them in the crosshairs or more likely the whole light aircraft sector

 

If you were to say 50% of Jabiru engine DONT have cooling sorted to operating limits (Id suggest 80%) and this leads to valve and throughbolt problems. It casts a very different light on results. This has been Jabiru's reasoning for ages but they havent appeared to do much about it. The better heads coincided with hydraulic lifter introduction.

 

Those CHT numbers are from the CAE engine manual, It is suggested 140 as max to give room for the fact they can keep rising even once conditions change.

 

 

[Bruce Tuncks]

How come there is more technical knowledge on this forum than resides in CASA?

 

There is an obligation of government that great power should be matched by great expertise.

 

My experience is in line with the postings here. The fault I can say Jabiru did was in allowing poor cooling setups to fly in the early days.

 

After realizing that 175 C was way too hot, ( let alone 200 which was the red-line at the time) I put on 4 sensors, sealed gaps in the ducts, increased the inlet area on the cowl, sealed the cowl to duct gaps, and reworked the oil-cooler area to make sure that most of the air entering the lower hole went to the oil cooler and not to just increasing the lower-cowl pressures. All well-known stuff.

 

This achieved about 15 degrees of reduction and the 140 degree max referred to here. All went well for years until I got caught out by what Oscar says is the Archille's heel when I did a ground-run incident.

 

These days, I reckon Jabiru have improved things a lot. The fine-finned motors and latest cooling ducts look ok to me, but I'm sure that poor operation can still cause harm. Personally, if I were to hire out my plane, it would have a 4 channel recording CHT and a sheet of instructions about how to keep it cool.

 

 

[Geoff13]

Bruce

 

I would love to have a read of your sheet of instructions on how to keep it cool. I am aware it was just a comment but have you actually considered writing it.

 

 

[facthunter]

The time tested way is to fly faster ( safety re obstacles allowing.) Do it when you see the temp moving up, rather than wait till the limit (or above ) is reached. It would be better to have cowl flaps to adjust for changing conditions when in the air, and when taxiing. Something else to do but effective.Nev

 

 

[fly_tornado]

I'm with Greybeard, there's never been a more exciting time to have an off field landing, maintain your agility by keeping a good landing site close by. Roll on the ideas boom...

 

 

[Oscar]

While everyone is arguing the details/numbers/stats/rubarb rubarb/waffle/ mines bigger than your's etc back on topic, too many engine related failures are occurring. If it's an issue with the design (regardless of who make the damn thing) or the numb nutz manipulating the throttle then maybe some of the NASA scientists with all of the answers could put a smidgen of their efforts into sorting out the problem(s). Rather than excrementing over and over about the exact percentage of who cares.Or maybe just go flying.......

I'd agree: too many engine failures are occurring. However, in terms of relative engine serious SAFETY issues measured by results, the concentration on Jabiru seems to be at the very least, a pre-determined conclusion that the ATSB report sought to validate.

 

Right up the front of the ATSB report: starting on p.8 of 38 pages, is a list of the 18 'high risk engine failure or malfunction occurrences' in the period and for the group under consideration - three of which resulted in fatalities.

 

I count three known Jab. engines in that lot: three in Jabirus - of which two at least were amateur-built ( the LSA, which should have been quoted as an LSA55 to be correct, may or may not have been a kit-build.) Zero fatals.

 

I count four known rotax-powered factory-build aircraft: two Tecnams, one Hughes Lightwing, one Aeroprakt A-22. One fatal.

 

I count three known Lycontinental-powered aircraft: the PA-38, Lancair, and Pitts. One fatal.

 

I count one highly likely VW conversion: the Rand Kr2. Fatal.

 

Of the 7 'unknown' engine aircraft, one - the Super Diamond - was reasonably likely to have been a Jab. engine: fatal. The Rans S7 was almost certainly rotax-engined. The two Visions, the Murphy, the Skyranger and the Pulsar were probably rotax-engined.

 

So: a reasonable assumption ( and why the ATSB report - considering it was focussed on engine reliability - did NOT mention the specific engines for each of the 18 'high risk engine failure or malfunctions' listed is, at the very least, a curious anomaly in the report: if that breakdown was intended to provide authentic information regarding engine failure / malfunction, the engines involved would have surely been included in the explicit summary details?) is that:

 

Four were Jabiru engines;

 

Nine were rotax engines;

 

Three were Lycontinentals;

 

One was a VW conversion.

 

The ATSB report collated statistics over six years of operations. That is sufficient, I contend, to be statistically useful.

 

On a very rough estimate of hours flown, Jabiru aircraft amassed around 450,000 flight hours. Let's say, conservatively, 400,000 hours. That equates to one 'high risk' engine event every 133,000 hours, or an average of one 'high risk' fevent about every two years across the entire Jabiru fleet. At an average of around 50 hours/year for private operation, an individual private Jabiru owner should expect a 'high risk' event once in every 2,660 years of operation: let's be conservative, and say once every 1000 years of operation. To be responsible owners, don't leave your Jabiru to your successors without a suitable 'best use by' date of around AD3100 noted.

 

Across the FTF fleet using Jabiru engines, averaging around 350 hours/year, they should be alarmed as a group to expect a 'high risk' failure once every 380 years of operation. If there are say 60 FTFs using say 2 Jabs. per FTF, then each FTF might reasonably expect a 'high risk' event once in about every three years. I wonder what the GA flight training average 'high risk' engine failure rate is - given that a C172 is less safe than a Jabiru....

 

 

[Kyle Communications]

Oscar.....are you actually reading the drivel you are posting?....a high risk event every 380 years...............stop smoking that tomato plant dude

 

 

[Oscar]

Provide me with your calculations from the statistics contained in the ATSB report. If I've made a mathematical error, then I'll happily acknowledge it. Otherwise, just saying 'you're smoking sh1t' is as valid as anything FT posts.

 

 

[fly_tornado]

Oscar the numbers are the numbers, you need your own numbers, preferably $10 and $20s if you want Senator O'Sullivan to work his magic to free the Jabirus.

 

Remember its an election year, so your contribution to aviation safety will make a difference.

 

 

[billwoodmason]

Re cooling - has there been a definitive article written by anyone (Jabiru included) explaining in detail the measures to take to ensure cool running of all the variants of Jab motors. (I know there has been posts on this site about baffles and airflow etc). It would be enormously helpful to all Jab owners if a set of drawings or a kit was available to easily modify existing engines. I realise certified engines cannot be legally altered however it would be helpful for experimental owners and those who were willing to take a punt on the advantage of a cooler running engine.

 

Come on Oscar prompt your contact into action.

 

 

[octave]

I'm with Greybeard, there's never been a more exciting time to have an off field landing, maintain your agility by keeping a good landing site close by. Roll on the ideas boom...

FT Perhaps I am misinterpreting your post but I can't understand why you seem to get off on the hardship of your fellow pilots who own Jab aircraft. For the record I do not own or fly a Jab, I have no particular interest in the CASA Jab situation, I do not fly anything at the moment that has a Jab engine although I do have 20 minutes up in a Jab which I enjoyed flying and would love to do again. The rest of my hours are flying behind a Rotax (504 in the 80s and a 912 since then) For the record I do not really know if Jab engines are the most dangerous aero engine or not and if CASAs actions are rational or justified. I do not have time to look deeply into to this because I AM BUSY ACTUALLY FLYING.

 

If CASAs actions ARE justified, I have nothing but sympathy for my fellow pilots who own or fly a Jab.

 

There are many fascinating posts in this thread from members who obviously have actual engineering and mechanical knowledge on both sides, however your posts seem to comprise only of pointless taunts.

 

By the way Phil have finished restoring either of your 2 Titan Tornados and are you flying them?

 

I really am open to all sides of this argument but I am getting sick of trollish type comments that add absolutely nothing of substance to the debate.

 

 

[Kyle Communications]

Oscar maybe I am doing the hooch too but those numbers you are extrapolating are fancifull....mind you I havent sat down to do the maths on the figures but on the numbers I have seen published here.... but those figures of yours just are not even common sense..... from my very quick figures done in my hooch affected head.

 

Maybe I need to go back to school

 

 

[Oscar]

You are someone who works with detailed science - electronics design requires calculation of values.

 

So: take the figures and information supplied in the ATSB report, do the maths, prove me wrong. I have put out my calculations fpr inspection. If you have reason to rubbish them - and you may be entirely correct - then do the work and put up the counter-proposition.

 

 

[DrZoos]

Oscar seriously...if your numbers are remotely correct we wouldnt even be discussing this, we would never hear of a jab failure, we wouldnt know jabs had cooling issues and we wouldnt know what a through bolt was , the size or the difference between valve lifters....

 

But alas we do...owners and observers have spoken about them with amazing regularity over many years....

 

Your figures are fanciful at best...and your assumptions about which aircraft had which engines are as ill founded as what you acuse CASA of doing, unfounded statistics

 

I dispute CASA's numbers, but creating a new set of fanciful data doesnt help

 

 

[aro]

Oscar maybe I am doing the hooch too but those numbers you are extrapolating are fanciful

That was my initial impression, but working from the numbers in the report I get about the same results. The important point to note is that it is only working from the failures classified as "high risk" by the ATSB - 6% of the total failures.

 

I don't buy the numbers calculated for FTFs though - if the high risk failure rate is 4 in 400,000 hours, to get 1 every 3 years a FTF would need to do 30,000 hrs/year. If you have 60 FTFs averaging 1000 hrs/year you would expect a high risk failure every 2 years across all FTFs,

 

If the failure rate for private owners is 1 in about 2000 years, if you have 2000 owners you can expect to see someone have a high risk failure every year.

 

Then you have to ask the questions: "How does it compare to other engines" and "Is that acceptable".

 

The biggest problem with these figures is that the number of high risk failures is too low for the figures to be accurate. Change the classification of one entry and it makes a big difference to the result.

 

 

[Kyle Communications]

Anyone can make any set of numbers have a result of whatever you want....I have seen 1 + 1 = 0 and it all looked correct to me. This is where its all a crock. The fact of the matter is there is a lot of jabiru engines out there that have gone bang. This is a fact! there are a lot of Rotax engines out there and not so many have gone bang this is also a fact. There are GA engines out there and they go bang too.

 

You just look at the amount of bangs for amount of engines out there and see the results...I dont give a toss whether its a "high risk" or not...perfectly good running engines can go bang.

 

I personally know of at least 10 four stroke RAA engines that have failed for some reason or another over around the last 10 years or so. NONE were ever reported to any authority. Out of that lot there were 8 jabiru and 2 rotax. This makes me wonder how many ACTUAL failures there are out there that have NEVER been reported. So the numbers that are all argued over here is really a moot point.

 

All I can be sure of is that for me and me alone my backside will never be in a jab powered aircraft until they sort their sh*t out. I fly a Rotax and am quite comfortable with the "risk" I take every time I fly. I do look after my engine very well and make sure I do all the regular oil and filter changes, I fastidiously check all the numbers on the EMS when I am flying and monitor them for any minor out of the ordinary changes. To date I have not had any reason to feel uncomfortable when sitting behind the 912ULS because if the fan ever stops I am quite sure I can get myself down in one piece. I can assure you I have no hesitation of pointing her between 2 trees and using the airframe as a brake if it is necessary without one feeling of regret. Any flying is a risk....some are prepared to take more risk than others...I like to err on the lesser of 2 evils side

 

 

[microman]

Couldn't agree more - I just completed a flight from Rangiora to Nelson and return, involving at least 1 1/2 hrs over mountains with no landing areas whatosever - I am actually a slightly nervous pilot, and wouldn't have done that trip in the days when I flew behind two-strokes - or any other engine I didn't have complete confidence in. The 912ULS is a fabulous engine - yes, its expensive (though I bought a low-time secondhand engine) but I can climb at full power anytime I need to and the temps stay well within limits. In 30 years of flying I cant remember one case of a 912/912S having a serious engine malfunction - the only stoppages I can recall were due to faulty maintenance on the part of the owner. My earlier aircraft, a Jodel D18 with a 912S suffered an engine failure (over water but within gliding distance of land and the forced landing was very skillfully executed by my co-pilot into a small paddock on the coast) - however it turned out that I had not secured the balance tube between the carbs properly. It came off and the engine stopped immediately. My fault entirely, and after resecuring it, we took off again.

 

 

[jetjr]

Much prefer an accident in Jabiru than almost all other airframes

 

Evidence seems to say you are safer even with more chance of an engine fail. If you could get a 912 in Jab airframe your view would be more acceptable

 

Its poor science to manage risk on potential risk instead of actual

 

The 912 is an exceptional engine, no doubt BUT based on atsb and casa approach it too is a few prangs from being classed unacceptable risky. Already well over their acceptable rate and rising

 

 

[Oscar]

That was my initial impression, but working from the numbers in the report I get about the same results. The important point to note is that it is only working from the failures classified as "high risk" by the ATSB - 6% of the total failures.I don't buy the numbers calculated for FTFs though - if the high risk failure rate is 4 in 400,000 hours, to get 1 every 3 years a FTF would need to do 30,000 hrs/year. If you have 60 FTFs averaging 1000 hrs/year you would expect a high risk failure every 2 years across all FTFs,

If the failure rate for private owners is 1 in about 2000 years, if you have 2000 owners you can expect to see someone have a high risk failure every year.

 

Then you have to ask the questions: "How does it compare to other engines" and "Is that acceptable".

 

The biggest problem with these figures is that the number of high risk failures is too low for the figures to be accurate. Change the classification of one entry and it makes a big difference to the result.

Thanks for actually LOOKING at what the ATSB produced, Aro, rather than shooting from the hip without even reading and comprehending what THEY wrote and what I quoted. Perhaps I should have made the 'high-risk' note in very large, bolded, and friendly letters.

 

Since there are about 1300 Jabs. on the RAA register, and I think only about 100 or less on the VH register, then with let us say ( and here I DID take a guess, for sure) about 120 in service with FTFs, that means about 1300 - roughly - in private hands. So: feeding back into the figures you got: yes that would mean roughly, for the six years covered by the ATSB report:

 

one 'high risk' every about 1.5 years across the Jab. private fleet, or 4 in 6 years

 

and one every two years for the FTF fleet, or 3 in six years.

 

Giving us a total of 7 in 6 years.

 

The ATSB report lists the 18 'high risk failures' by aircraft type: and it lists 4 Jabirus.

 

Therefore, I would suggest that my figures, that you have looked at, err on the side of being higher than what the ATSB has actually reported in their 'high risk' category. I didn't make up that category, nor did I make up the listing of aircraft in that category. The ATSB evidently thought it important to provide detailed information about that category, in a prominent place in their report.

 

 

[Camel]

Statistics mean nothing unless you have the right information ! Aircraft running out of fuel should not be counted, siezure from no oil ! Running an engine too lean or overheating ?

 

There are human error failures, mechanical design fault failures and faulty part failures. There is also the fact that engines are listed as brands and there are models of engines that are more prone to failure. Unless statistics categorised in their respective failure catergory then it is impossible to use these statistics.

 

Every engine has its quirks, some don't like certain revs due to harmonics, some like to rev without load, some like load and some don't get hot due to over efficient cooling where others are very pronged to run hot.

 

As I have a Jab engine I treat it as I believe what suits this engine and the Lycombing O320, Rotax 582 and 912 I've had I have treated according to recommendations from POH. I have seen many people mistreat these engines the same as some people mistreat car engines and wonder why they give trouble. An example of being kind to a Lycombing was climb and level off every 500 ft and cool engine, full rich during climb and full power, lean when achieved desired altitude, not to richen mixture until bottom of descent from Higher altitude and keep a little power on during descent. If you don't treat your engine right expect problems.

 

People say you should not have to baby and aircraft engine and should be robust to take a little abuse and there is some truth in this but I see people idling Rotax engines with the engine falling apart from vibrations and I see people steep climb Jabs for long periods and idle for long periods and these are serious abuse of an engine that is built light to deliver high performance. Engine management is important and I wonder how many people really care or do it especially when they hire a plane ?

 

When I worked on Expensive European high performance cars it was the ones that did a lot of miles that gave the best service others were plagued with problems and called unreliable but they weren't driven hard enough to get the temps and oil up to operating optimum temp. Taxis are the best example of this !

 

So the ATSB stats are not a reliable source in my opinion.

 

 

[Bruce Tuncks]

Here's how the Jabiru engine should be operated in my opinion....

 

1. Use 150 C as your redline, that is the hottest cylinder. Watch the CHT's carefully, especially on the ground. Be especially watchful on windy days taxying with a tailwind, when the hottest cylinder may change.

 

2. Climb initially at full throttle, then at about 1000 ft throttle back and go into cruise-climb at 80 knots.

 

3. It the CHT ever approaches 150 then lower the nose and let the speed go up to 90 knots and throttle back to level flight or very small climb until it cools down. This means climb in steps on a hot day.

 

4. If none of the above work to keep it cool then report a fault. The cooling needs modifying.

 

5. Remember the standard Jabiru CHT under-reads on a hot day.

 

6. Bear in mind there is a recording CHT in this plane and if you disregard this stuff you will have to pay for a new engine.

 

7. Don't ever do what I did and run the engine hard on the ground.

 

 

[Kyle Communications]

Much prefer an accident in Jabiru than almost all other airframesEvidence seems to say you are safer even with more chance of an engine fail. If you could get a 912 in Jab airframe your view would be more acceptable

Its poor science to manage risk on potential risk instead of actual

I have never said I had a issue with the Jab airframe. It has proved to be a very tough airframe...born out of how many survivable out landings even reported here on these forums...many more than other types of airframes and most here will agree. I have always maintained if you put a Rotax up the front then Jab would sell so many new aircraft they would be in a totally different financial position especially even in the worldwide market place. The problem is the boss is so pig headed about it he will not do it even if the world was ending if he didnt do it. I just dont understand the mentality of it. The current Jab airframes with Rotax engines which are only a few are too nose heavy and I have seen this first hand and spoken to the pilots and owners of that aircraft base at Caboolture...which I think has been sold now. Jab need to make the necessary mods to make it correct for W&B then it would be a great bit of kit giving them the time they need to work though the Jab engine issues they have. I am a firm believer in having a local engine manufacturer and would support them IF the engine was a lot more reliable and not so finicky with the current operational issues. In my PERSONAL opinion it is NOT anywhere near to the standard I would fly behind one. The Rotax is not perfect and neither is any other engine but I calculate the risk in a Rotax powered aircraft to be far less than a current jab powered aircraft. I would love a 6 cyclinder Jab engine in the new airframe I want to build for the hp and the weight but not at the moment

 

Mark

 

 

[Kyle Communications]

By the way I do monitor what is going on with the Camit version as it does seem to be much better but still not enough of them out there yet to make a informed decision but I think they are getting there and we will see how it goes. I just hope Ian bent can stay in business long enough to have me look at it being a viable alternative.

 

Mark

 

 

[REastwood]

Here's how the Jabiru engine should be operated in my opinion....1. Use 150 C as your redline, that is the hottest cylinder. Watch the CHT's carefully, especially on the ground. Be especially watchful on windy days taxying with a tailwind, when the hottest cylinder may change.

 

2. Climb initially at full throttle, then at about 1000 ft throttle back and go into cruise-climb at 80 knots.

 

3. It the CHT ever approaches 150 then lower the nose and let the speed go up to 90 knots and throttle back to level flight or very small climb until it cools down. This means climb in steps on a hot day.

 

4. If none of the above work to keep it cool then report a fault. The cooling needs modifying.

 

5. Remember the standard Jabiru CHT under-reads on a hot day.

 

6. Bear in mind there is a recording CHT in this plane and if you disregard this stuff you will have to pay for a new engine.

 

7. Don't ever do what I did and run the engine hard on the ground.

But the Jabiru POH clearly states that you can run the engine CONTINUOUSLY at 180 C - So, if engines are failing because they are run according to the POH then there is a problem. Why doesn't Jabiru change the POH accordingly?

 

 

[Bruce Tuncks]

Yes RE and I have to say my procedure is designed to stay well on the safe side, perhaps further than needed. But I do reckon that Jabiru have that limit too high for my liking.