Proposed Jabiru AD hot off the press

[Jase T]

http://services.casa.gov.au/airworth/airwd/ADfiles/UNDER/JABIRU/PADJABIRU-003.pdf?utm_source=Swift Digital&utm_medium=Email&utm_campaign=Airworthiness Directives

[RFguy]

yeah... Aileron Ctl Torque tube from the rear of the stick. there are probably quite a few cracked below the 4000 hours.

 

I have looked at two since that P-AD came out last week , both were not cracked, but both aircraft < 1000 h.

 

There would be some Jabiru maintainers here that would have seen a few, their comments would be interesting.

[Jaba-who]

On 11/12/2020 at 6:30 AM, RFguy said:

yeah... Aileron Ctl Torque tube from the rear of the stick. there are probably quite a few cracked below the 4000 hours.

 

I have looked at two since that P-AD came out last week , both were not cracked, but both aircraft < 1000 h.

 

There would be some Jabiru maintainers here that would have seen a few, their comments would be interesting.

What???? 
No evidence of ANY and you even looked at some and there was no evidence of any but still saying “yeah there probably are quite a few cracked below the 4000 hours.  “
 

Someone will take this post and say “yeah, some guy on a forum said yep there’s quite a few of them so yeah CASA should be clamping down in bloody Jabirus again! “ 

No wonder Jab owners feel like a threatened species. For what it’s worth,  where I am there about half a dozen Jabs and I’ve not heard of anyone having the problem. 

For a touch of reality. 
CASA have had over a year since the original SB was put out by Jabiru. Since then, if you go by the wording of the PAD,  there has not been any or another incidence of this problem. The report clearly says there has been one case which we can take to be the original case. 

Now the way I read it, it is a requirement for essentially all Jabirus, depending on how you interpret the convoluted Applicability paragraph. But that’s not the problem. I have no issue with it being part of the 100 hourly. It’s bugger all as far as an inspection goes. 

But I’m left not being sure about the reporting paragraph.

 

“2. Report the results of the inspection to CASA via the Defect Report System.”

 

It seems to me that once the inspection is done, then this AD requires me to report to CASA the outcome of the inspection, whether a crack is found or not. So every year, assuming no problem is found I still have to report to CASA and if I don’t then I am in breach the AD. I stand to be fined or have punitive action taken against me for not reporting that I have not got a problem. 
 

I’ve  never come across any AD in over 25 years of flying where I am required to report to CASA when there is nothing wrong with an aircraft. 
 

What’s going on here? 

Edited December 15, 2020 by Jaba-who

[Thruster88]

Jaba, this AD only applies to VH jabiru's. All  jabiru's are subject to JSB 042-1. The manufacturer has rightly stated that all SB's are mandatory so the AD is a waste of time, another unnecessary duplication.  Only VH jabiru's must report results to casa, non VH report defects only to the manufacturer.  Reporting all results of AD's is not unusual.  

[turboplanner]

7 hours ago, Jaba-who said:

What???? 
No evidence of ANY and you even looked at some and there was no evidence of any but still saying “yeah there probably are quite a few cracked below the 4000 hours.  “
 

Someone will take this post and say “yeah, some guy on a forum said yep there’s quite a few of them so yeah CASA should be clamping down in bloody Jabirus again! “ 

Yes, RF this is just a routine CASA safety message, precautionary to the owners and doesn't imply every one is going to crack.

7 hours ago, Jaba-who said:

“2. Report the results of the inspection to CASA via the Defect Report System.”

 

It seems to me that once the inspection is done, then this AD requires me to report to CASA the outcome of the inspection, whether a crack is found or not. So every year, assuming no problem is found I still have to report to CASA and if I don’t then I am in breach the AD. I stand to be fined or have punitive action taken against me for not reporting that I have not got a problem. 
 

I’ve  never come across any AD in over 25 years of flying where I am required to report to CASA when there is nothing wrong with an aircraft. 
 

What’s going on here? 

Probably just CASA wanting to collect data with x number of zero cracking and Y number of cracking.  How long does the inspection take?

[Jaba-who]

30 minutes ago, turboplanner said:

Yes, RF this is just a routine CASA safety message, precautionary to the owners and doesn't imply every one is going to crack.

Probably just CASA wanting to collect data with x number of zero cracking and Y number of cracking.  How long does the inspection take?

That’s not the point Turbs. The inspection which I have done severally times now since the SB came out takes about 30 seconds. 
what is the problem is that if I forget to report to CASA that I did the inspection, and found nothing, then next time I go flying I have breached this AD and have committed a crime. 

[Jaba-who]

1 hour ago, Thruster88 said:

Jaba, this AD only applies to VH jabiru's. All  jabiru's are subject to JSB 042-1. The manufacturer has rightly stated that all SB's are mandatory so the AD is a waste of time, another unnecessary duplication.  Only VH jabiru's must report results to casa, non VH report defects only to the manufacturer.  Reporting all results of AD's is not unusual.  

Actually it’s not usual and it’s never happened before as far as I am aware. 

I have not seen another AD in 25 years of doing maintenance and owning aircraft where AD  inspections must be reported to CASA that NO DEFECT has been found. The AD being complied with gets written in the aircraft (and engine log book  if applicable) maintenance log book. 
That’s the bit I interpret as being a problem. 
 

It says the results of the inspection must be reported, which I read as even when no crack is found.  

[turboplanner]

13 minutes ago, Jaba-who said:

That’s not the point Turbs. The inspection which I have done severally times now since the SB came out takes about 30 seconds. 
what is the problem is that if I forget to report to CASA that I did the inspection, and found nothing, then next time I go flying I have breached this AD and have committed a crime. 

Having worked for manufacturers all my life I know the frustration of having product failures of all types; 

• Intermittant failures where some products would fail
• Life cycle failures where every product would have a failure after a certain number of hours or distance
• Irregular failures where all products would fail, but at different times.

We will usually fix all problems we can find, but the frustrating thing is only a few customers ever tell us, and we have no means of knowing which of those three types of problem it is unless we get data in.

 

With life cycle failures, we can replace the suspect part at a regular service under the failure point, or we can call the product in and provide a loan while the faulty product is being replaced - sost the customer nothing.

 

Irregular failures are handled by stocking up on replacement parts and providing loan products

 

Intermittant failures are the most difficult because it's so difficult to diagnose what the cause is. 

 

Air Bags in cars are blown up by the blast from a charge of Ammonium Nitrate, the same material favoured by terrorists. Takata got something wrong in the engineering and metal fragments started killing people. The airbags in our cars were replaced by the dealers during routine service so it never cost us a cent. However maybe ten years after the event there are still about 30,000 Australians who will not bring their cars in for replacement air bags.

 

So in the automotive and transport industries we have this blind spot where we research as best we can from part of the population, but the rest don't find it necessary to tell us enough to make decisions in there interest.

 

In the aviation industry we have a Safety Authority which adds another layer and are given tools to compell people to provide this information.

How much safer is it to be able to look at reports from all the VH Jabirus and know that 0.6% have cracked at 4000 + hours, but 99.4 have not, That tells me that there is no reason for any owners to have to replace the tube under 4000 hours, and more research is required on the 0.6% before committing to replacement at 4000 hours.

 

Armed with feedback an Engineer has a much better chance of fixing the problem.

 

 

[Blueadventures]

1 hour ago, Jaba-who said:

That’s not the point Turbs. The inspection which I have done severally times now since the SB came out takes about 30 seconds. 
what is the problem is that if I forget to report to CASA that I did the inspection, and found nothing, then next time I go flying I have breached this AD and have committed a crime. 

Hi Jaba They say only one aircraft in Australia is affected, is that yours, VH?

 

I drove past Atherton on Sunday and airfield looks nice, actually stayed overnight at the next door park and now in Cooktown.

[Jaba-who]

26 minutes ago, Blueadventures said:

Hi Jaba They say only one aircraft in Australia is affected, is that yours, VH?

 

I drove past Atherton on Sunday and airfield looks nice, actually stayed overnight at the next door park and now in Cooktown.

Hi Blue

Nope mine wasn’t the one that it happened in. That was a training aircraft somewhere in ?NSW that had about ?8500 hours in it. 

Atherton is a nice airport. Grass strip, no landing fees. Can be a bit gnarly at the northern end in a  cross wind. Pleasant aviation community there. 
 

[Jaba-who]

2 hours ago, turboplanner said:

Having worked for manufacturers all my life I know the frustration of having product failures of all types; 

• Intermittant failures where some products would fail
• Life cycle failures where every product would have a failure after a certain number of hours or distance
• Irregular failures where all products would fail, but at different times.

We will usually fix all problems we can find, but the frustrating thing is only a few customers ever tell us, and we have no means of knowing which of those three types of problem it is unless we get data in.

 

With life cycle failures, we can replace the suspect part at a regular service under the failure point, or we can call the product in and provide a loan while the faulty product is being replaced - sost the customer nothing.

 

Irregular failures are handled by stocking up on replacement parts and providing loan products

 

Intermittant failures are the most difficult because it's so difficult to diagnose what the cause is. 

 

Air Bags in cars are blown up by the blast from a charge of Ammonium Nitrate, the same material favoured by terrorists. Takata got something wrong in the engineering and metal fragments started killing people. The airbags in our cars were replaced by the dealers during routine service so it never cost us a cent. However maybe ten years after the event there are still about 30,000 Australians who will not bring their cars in for replacement air bags.

 

So in the automotive and transport industries we have this blind spot where we research as best we can from part of the population, but the rest don't find it necessary to tell us enough to make decisions in there interest.

 

In the aviation industry we have a Safety Authority which adds another layer and are given tools to compell people to provide this information.

How much safer is it to be able to look at reports from all the VH Jabirus and know that 0.6% have cracked at 4000 + hours, but 99.4 have not, That tells me that there is no reason for any owners to have to replace the tube under 4000 hours, and more research is required on the 0.6% before committing to replacement at 4000 hours.

 

Armed with feedback an Engineer has a much better chance of fixing the problem.

 

 

Nope - too much extrapolation to non-relevant scenarios. 
 

There are only 65 Jabiru’s on the VH register.  They form a statistically irrelevant cohort in the overall fleet across RAAus, LSA and GA. Any figures collected from them will be irrelevant to the overall statistics and interpretation of those statistics. 
 

[Kenlsa]

While I don’t have a problem with the AD it is over a year old.

we all are aware of glaciers that move quicker than CASA.

 

Ken

[turboplanner]

1 hour ago, Jaba-who said:

Nope - too much extrapolation to non-relevant scenarios. 
 

There are only 65 Jabiru’s on the VH register.  They form a statistically irrelevant cohort in the overall fleet across RAAus, LSA and GA. Any figures collected from them will be irrelevant to the overall statistics and interpretation of those statistics. 
 

I understand your beef is with the mandatory part of the reporting.

Thruster said: "non VH report defects only to the manufacturer" For those aircraft the manufacturer might be doing the mandatory reports?

If the RA owners are not reporting to the Manufacturer or the Manufacturer is not reporting to CASA, then I agree, the system breaks down.

[Jaba-who]

2 hours ago, turboplanner said:

I understand your beef is with the mandatory part of the reporting.

Thruster said: "non VH report defects only to the manufacturer" For those aircraft the manufacturer might be doing the mandatory reports?

If the RA owners are not reporting to the Manufacturer or the Manufacturer is not reporting to CASA, then I agree, the system breaks down.

Nope you miss the point.
there is no problem with a mandatory report of finding a crack when one is found.  
 

The AD requires owners to report when NO crack is found and that is mandatory.
 

There is no requirement in the SB to report that NO Defect has been found when doing the inspection. The manufacturer will NOT be reporting to CASA that owners have not reported when NO crack is found.
 

The only people who stand to get into trouble and ? be fined and held accountable is owners of VH Aircraft who don’t report that they have NOT found a crack. 

Edited December 16, 2020 by Jaba-who

[Jaba-who]

Actually now I reread the applicability paragraph they do not include any of the J200 or J400 series aircraft which make up almost all of the current VH fleet. 
The models named are all those old types like ULs, STs, etc etc. And then only to certified models. 

So maybe this applies to very few or no aircraft anyway. 

[turboplanner]

7 minutes ago, Jaba-who said:

Actually now I reread the applicability paragraph they do not include any of the J200 or J400 series aircraft which make up almost all of the current VH fleet. 
The models named are all those old types like ULs, STs, etc etc. And then only to certified models. 

So maybe this applies to very few or no aircraft anyway. 

Maybe, but let's work on the previous 65 units as an example.

 

If CASA only received reports from 4 owners regarding cracking, there are 65 out there in unknown condition; they might all be OK, or some people may not have got around to checking - too important for a safety issue to just leave it hanging.

If CASA receives 4 reports indicating cracking, and 61 reports indicating no cracking, it has an accurate assessment of the spread of the problem.

I've always solved similar issues by phoning every customer - makes a huge different in keeping the fleet working.

 

 

[RFguy]

and when I said
"there are probably quite a few cracked below the 4000 hours"

 

- that is purely based on probability.  is a bell curve.  If there are tubes cracking > 4000 hours, there will likely some non zero number cracking 2000-4000 hours.

 

[RFguy]

and if there were 4 units for Jabs > 4001 hours, there is probably going to be 'not very many' below that.

 

Nevertheless, given the failure behaviour of Aluminium, especially in this  torquey service, it's an easy one to check. 

I see alot of failures like this in radio antennas on a mast , where the antenna produces a net torque (in the wind) , and there is a point stress in a bolt hole, that leads to a propagating crack . 

Edited December 16, 2020 by RFguy

[Blueadventures]

5 hours ago, Jaba-who said:

Hi Blue

Nope mine wasn’t the one that it happened in. That was a training aircraft somewhere in ?NSW that had about ?8500 hours in it. 

Atherton is a nice airport. Grass strip, no landing fees. Can be a bit gnarly at the northern end in a  cross wind. Pleasant aviation community there. 
 

Ok,good. What I meant was not if yours had cracks just if yours was the only one on the au register, VH that needed the precautionary checks. Cheers and best regards.

[Jaba-who]

3 hours ago, RFguy said:

and when I said
"there are probably quite a few cracked below the 4000 hours"

 

- that is purely based on probability.  is a bell curve.  If there are tubes cracking > 4000 hours, there will likely some non zero number cracking 2000-4000 hours.

 

Nope. That is choosing  the wrong type of statistical analysis for this situation. 
 

Statistically speaking it is not possible to produce a valid bell curve from a single event. You must have some cases above and below the mean so that a gradient can be made to find the standard deviations etc. A single case can only produce a linear spike on the x axis. No statistical capacity to produce a bell curve. 
That’s assuming a true single case event and in the entire history of jabiru ( some 30 years) this appears to be the only event ever reported. 
 

so the single event happened in an aircraft with just over 8500 hrs. ( According to JSB042-1)  Not 4000 hours - that’s the arbitrary selected hours by Jabiru to make the inspections. 

But Ok - Assuming other cases (?which there is no evidence ) enough to produce a bell curve - there is a reasonable chance the approach to zero line in this fictitious curve may be so flat below 4000 hours that it reaches the near zero Y axis line and therefore for all intends and purposes is zero. ( In this type of statistical analysis you can’t have less than an integer value  of 1 case - you can’t have say 0.5 aircraft having fractured control rods. It has to be 1 or 2 or 3 etc. )  
So it is entirely  possible, in fact probable that there are  zero cases below 4000 hrs. 

 

 

[Jaba-who]

4 hours ago, turboplanner said:

Maybe, but let's work on the previous 65 units as an example.

 

If CASA only received reports from 4 owners regarding cracking, there are 65 out there in unknown condition; they might all be OK, or some people may not have got around to checking - too important for a safety issue to just leave it hanging.

If CASA receives 4 reports indicating cracking, and 61 reports indicating no cracking, it has an accurate assessment of the spread of the problem.

I've always solved similar issues by phoning every customer - makes a huge different in keeping the fleet working.

 

 

But the point here is that if any of those 61 forget to contact CASA AND EVERY  owner of the thousands of RAAus and LSA owners don’t contact Jabiru or CASA ( which they will because they are mot required to ) 

then the very small number of the VH aircraft become meaningless in the mix. 
 

But to get back to my concern - it’s not the statistical validity  or lack of it I don’t care about reporting a crack if I find one - it’s the fact that if I forget to tell CASA I had NO cracks or if I do tell them but my response gets lost along the chain through CASA then given the Strict Liability function of just about all aviation law then I will be guilty of an “aviation crime.” Without mitigation. 

That’s what  I said right from the start but everyone seems to have missed that. 

[turboplanner]

29 minutes ago, Jaba-who said:

But the point here is that if any of those 61 forget to contact CASA AND EVERY  owner of the thousands of RAAus and LSA owners don’t contact Jabiru or CASA ( which they will because they are mot required to ) then the very small number of the VH aircraft become meaningless in the mix. 
 

That's the point I've been trying to make to you. That's why they make it compulsory for everyone to submit a report, whether crack or no crack.

Because many people couldn't care less, that's why there's a penalty for not submitting a report.

How hard is is to send in a report for no cracks?

It's not your concern what happens with the RAA aircraft.