Jabiru engine life times

[skeptic36]

That seems to suggest that somewhere more than 1,000 Jab owners are not sufficiently concerned about their engine life to contribute to this forum. .

Seems a strange thing for one so intelligent to say.

I bet some of those 1000 Jab owners don't even turn their computer on let alone visit a forum of any sort:pc revenge:

 

 

[01rmb]

About time some serious petitioning be directed towards the RAAus and CASA to implement these modifications to the 24: aircraft that are obviously working and improving the reliability of these engines.

Isn't that the key to solving the problem? Actually working with Jabiru to solve the reliability issues achieve a whole better outcome than knocking what is arguably the biggest gain in recreation aviation in Australia. If we take away the hurdles and no doubt excessive costs to certifying engines or modifications Jabiru, CamIt and whoever else has done a reasonable level of testing could introduce reliability gains for consumers easier and cheaper.

 

I am sure jabiru would like to do more to improve their product where possible but are hobbled by bureaucracy and the resultant costs. If you have gone through the costs to certify your product but every change costs a fortune to do it again I am sure that you would be hesitant to do anything unless it was absolutely necessary.

 

Maybe the RAAus board members could help the industry grow rather than try to bring it down by working with CASA and the industry to achieve a win win situation for everyone. I know I would like to have the most reliable aircraft possible without the excessive costs.

 

 

[Russ]

That seems to suggest that somewhere more than 1,000 Jab owners are not sufficiently concerned about their engine life to contribute to this forum. My appreciation from contributing to this site is is that something like 20 or so forum members are vehemently opposed to Jabirus, and I frankly think I can be of more use providing what information I can to the other 1,000 plus than fighting with what may well be described as the 'rump' of Jabiru commentators. .

How do you conclude that 1000+ Jab owners frequent this forum to engage as you refer. ( perhaps 30.....50.....perhaps )

 

 

[Oscar]

How do you conclude that 1000+ Jab owners frequent this forum to engage as you refer. ( perhaps 30.....50.....perhaps )

Nope, that's not what I said. I'm saying that somewhere in the vicinity of 1,000 Jabiru owners do NOT contribute to this forum, hence we have a very few to represent the whole Jab owner population - as you suggest. Therefore, extrapolation of Jab experience from that small a number is really not likely to be a reliable indicator.

 

 

[Keenaviator]

Isn't that the key to solving the problem? Actually working with Jabiru to solve the reliability issues achieve a whole better outcome than knocking what is arguably the biggest gain in recreation aviation in Australia. If we take away the hurdles and no doubt excessive costs to certifying engines or modifications Jabiru, CamIt and whoever else has done a reasonable level of testing could introduce reliability gains for consumers easier and cheaper.I am sure jabiru would like to do more to improve their product where possible but are hobbled by bureaucracy and the resultant costs. If you have gone through the costs to certify your product but every change costs a fortune to do it again I am sure that you would be hesitant to do anything unless it was absolutely necessary.

 

Maybe the RAAus board members could help the industry grow rather than try to bring it down by working with CASA and the industry to achieve a win win situation for everyone. I know I would like to have the most reliable aircraft possible without the excessive costs.

Absolutely hit the nail squarely on the head O1. Laurie

 

 

[motzartmerv]

The real key to sorting the problem is in the reporting. The only way we will get it fixed is if we make noise, and by that I mean furnish the people who can make a change, with the reports when you find things not up to scratch, or defective. Unfortunately you cant report an "attitude' from the factory, but you can report QA issues. Defective parts. Defective repairs etc. report it all!

 

Only takes a few minutes to fill in the form and send it in. keep accurate records and if your 24 rego'd and hiring the aeroplane- keep bloody accurate records of everything you do and make sure you dont deviate from the maint manuals.

 

 

[Guest Andys@coffs]

Isn't that the key to solving the problem? Actually working with Jabiru to solve the reliability issues achieve a whole better outcome than knocking what is arguably the biggest gain in recreation aviation in Australia. If we take away the hurdles and no doubt excessive costs to certifying engines or modifications Jabiru, CamIt and whoever else has done a reasonable level of testing could introduce reliability gains for consumers easier and cheaper.I am sure jabiru would like to do more to improve their product where possible but are hobbled by bureaucracy and the resultant costs. If you have gone through the costs to certify your product but every change costs a fortune to do it again I am sure that you would be hesitant to do anything unless it was absolutely necessary..

I guess it all comes down to defining "absolutely necessary...."

 

I would think that if groups of flyers start talking about those unreliable jabiru's and the factory goes from delivering just as many as they can make say 4-5years back where it was at least 9months wait to have one delivered...to today where you can have any model just as soon as you pony up the $ cause there's quite a few finished ones available to immediately choose from then it would seem that for my business exposure there very well might be a degree of "absolutely necessary" coming to the fore....

 

How will I know when "absolutely necessary" has really struck home and Jabiru really do want to try and fix the issues? I'm guessing when they don't immediately dismiss any owner experience as merely poor Owner flying/maintenance/anything else but admit there is a problem. I posted previously that in my case my maintainer was replacing barrels and the ones delivered were not crosshatched correctly (Hone too fine) Jabiru rather than investigate and prove or disprove through technical evaluation merely said to the maintainer "It'll be fine use them as they are, they are in spec (sight unseen!) "! My maintainer could not in good conscience do that because he knew the bores would polish up and I'd be using way too much oil before 100hrs of use had transpired...

 

I don't expect that behaviour from a car parts supplier. To have it from a certified aviation engine manufacturer is just beyond acceptable in my opinion. As the end user I paid in addition to spare parts costs, restoration costs to have parts that were new restored to new specifications. How can that possibly be correct? My maintainer knows of another maintainer in central NSW who at the same time was doing the same type of job in isolation from my maintainer who independently discovered the same fault and also had to pay to have them honed correctly in a local machine shop.

 

All this talk about whether a poll does or doesn't show statistically if there is or isn't an issue is just noise IMHO. Ask any L2 , 3 or 4 who undertakes Deeper level maintenance on jabiru engines if there are problems with the engines and/or problems with Jabiru management and I'm pretty sure you'll be told pretty quick smart that there are issues....significant ones....and more the later issue than the former!

 

To be told by your maintainer that worn out valve guides and out of round pistons/bores is normal for a sub 200hr engine (of 2005 vintage) and expected speaks volumes to me...

 

The only saving grace in my case is that mine is 19 registered and Im not bound by some rule to only fly in a configuration that I personally judge to be unsafe.

 

In my case I had 4 years RAAF formal aircraft trade training and I maintained F111 and P3C orion aircraft electronic systems while I was in the RAAF I understood and followed the Jabiru maintenance manuals when it came to engine care and overhaul my engine failure was detected through normal maintenance and testing before it eventuated into an in flight failure. It was not owner mismanagement or bad maintenance I mean truly it was only 190hrs....how much maintenance is actually called for in 190hrs??????

 

A couple of teasers that Im aware of......

 

1) Jabiru state in their manuals that the solid lifters need to be gapped to 10thou..... My maintainer says that Jabiru verbally say that 10thou is not best and the gap should really be 14 thou.... and its been that way for years.....but the manual doesn't change

 

2) What is a safe operating temperature for CHT? The J manual from memory says max 200degrees Celsius with max continuous at 180degrees C with the time between the 2 not to exceed 5 mins. Yet in talking to my maintainer I was told if you hit 180your well into overheat range, exceed that and damage is happening...... when if ever will the manuals reflect reality...and the cooling system be modified to reflect the reality.

 

Andy

 

 

[fly_tornado]

Keep going Oscar, you are winning! Grind him down

 

 

 

[01rmb]

I guess it all comes down to defining "absolutely necessary...."

Andy - I absolutely agree - I am not condoning poor QA. If a product is not being produced as designed and failing because of that then there is a problem that must be addressed. It must be made fit for purpose and that includes maintenance in accordance with procedures and the normal behaviour of pilots to ensure the product performs as expected. Failure at low hours is not acceptable and should be made good by the manufacturer as a warranty claim. If I had a similar problem with my aircraft I would also be joining the line of disenfranchised owners.

What I am talking about is I would like be able to utilise an improved design or modification that has been endorsed by the manufacturer without losing my registration by having to go through a long winded and costly certification process. In essence, to allow 24 registered aircraft to take advantage of improvements such as those suggested from CamIT (and I am sure even Jabiru themselves) without loss of aircraft 24 registration which otherwise won't be made available because to certify the changes would cost more than what the business can afford. And with the state of aviation such as it is, few businesses can afford it because of the small volumes and low returns. I could do it with a 19 registration aircraft but why should I not be allowed to do it with a 24 registration aircraft and then not be able to use it for training or hire.

 

All recreation aircraft are produced to a weight and cost model to meet market demands. I would pay more for better quality but not for the unnecessary cost just for paperwork. I look at the possible improvements already in the market and wish I could do something about it but can't because I will lose the registration. If reliability improvements can be introduced with minimal cost then everyone wins. I believe we would see more improvements being introduced if this was the case.

 

As Ozzie said - it would be good to see RAAus lobbying CASA to allow these improvements to be introduced for the good of the recreational market.

 

Quality is still with the manufacturer to maintain...

 

 

[Oscar]

Keep going Oscar, you are winning! Grind him down

I don't want to have to, and it'd be way, way more useful to everybody if we didn't have this gaping chasm between the 'Jab. legs bad, other legs good' brigade and those who are trying to keep the overall commentary in some sort of perspective. I have never taken the position that Jab engines are perfect, have no faults, have no QC issues etc.; if that were my belief, then I'd not have spent my money on the CAMit upgrades (and they'll need an EO before I can use my engine, but I'll be continuing in 55-reg so I do have that luxury). I would, for instance absolutely concur with Andy re his experience of the cross-hatching (and Keith Rule at Cessnock is absolutely a Jab engine guru, his opinion is gold-standard as far as I'm concerned.)

 

However this whole area is way too complex to just push individual cases into 'Box A' or 'Box B' as some sort of 'proof' of what happened. For just how complicated it gets, one could take the Sting crash at Goulburn as an example. If one takes the (very, very extensive) report on the engine ( http://www.atsb.gov.au/publications/investigation_reports/2007/aair/aair200700054.aspx ) one could draw the conclusion that the crankshaft simply broke, and a 'Rotax knocker' group of the same temperament as some of the Jabernasties on this forum might take that plus the Rotax Emergency Safety Bulletin and trumpet that 'all Rotaxes have crap crankshafts.'

 

HOWEVER, if you also read the full Coroner's report ( http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCgQFjAA&url=http%3A%2F%2Fwww.recreationalflying.com%2Fimages%2FSmith%2520and%2520Guthrie%2520Finding%2520-%2520Final.doc&ei=-9LiUrmcPITriAejjYHYDQ&usg=AFQjCNGM2DoUc4oFTxfiyw141_kLZuo3DA&bvm=bv.59930103,d.aGc ) you'll realise that there are additional factors that ought to be considered. There's additional unpublished information that adds to the picture very considerably that was discovered during the work on the subsequent court case that leaves at least the possibility of a prop strike before that aircraft was sold. All in all it's a very tangled story and just saying that 'the crankshaft failed catastrophically' - which is the summary of the engine inspection report - does in no way cover the gamut of possible causes of the ultimate effect. The same goes for any engine failure, it's just not good enough to take the final effect and use that to stuff that case into the box of one's own choosing without knowing the full circumstances.

 

Jabs are ubiquitous in Australian skies. If the engines were as tough as the airframes, they'd be (as some have said here) a bloody world-beater, and for those who accuse me of stuffing 'propaganda' down people's throats, I make absolutely no apology for holding that opinion. There is no objective measure of what is or is not a 'world-beater' by which I can 'prove' my argument, nor that it can be disproven. It's just an opinion.

 

Jabs, like all RAA aircraft, get operated in many different circumstances. There is a significantly lower amount of quality control on those circumstances than for GA, just for a start. Take fuel: if you operate from a GA-oriented field in a GA aircraft, you almost without exception use 100LL coming from a refuelling facility that has a reasonably high rate of fuel turnover so what gets put in your tank is very, very likely to be a) of known quality, and b) pretty fresh.

 

Now take the case of an RAA aircraft operated from a small field. If you don't use the aircraft all that much, and you use e.g. 98 RON MOGAS, the fuel you topped up your tank with when you last shut down might be weeks or even more old. Depending on which brew it was (and don't kid yourself you can be assured that what the 'label on the can' said is necessarily kosher, MOGAS deliveries are way more arbitrary than Avgas deliveries), that fuel may be well less than 98 RON as the aromatics evaporate. So you go out, do all your checks, take off and climb out just as you have done successfully many times before - but this time, you get detonation from that old fuel and the through-bolts give up the ghost. It's not really 'operator error' - but the effect on the engine is the same, it is operated out-of-limits (quite unintentionally on the part of the operator), and thus gets a hammering it can't handle.

 

So what's the 'cause' here? It's most certainly not wilful operator error, nor a history of out-of-limit operation. Equally, the engine itself can't tell you 'I'm being fed crap fuel', other than by CHT readings. A skilful operator watching the CHT readings (and needing to have ALL heads reporting, btw) can act to keep the engine within limits - pull back on power, lower the ROC and increase the cooling airflow etc. If you're climbing out of a somewhat marginal field on a hot day in a busy circuit area, that's a bit of an ask. From the engine's POV, it is operator error in that is was operated out-of-limits; from the operator's POV they did everything as usual, and that's usually been good engine management practice. All in all, it's a bit of a 'sh1t happens' moment in reality - and yes, it costs money to rectify. You can't really put the 'blame' in either box and those who want their box of choice stuffed further full of 'evidence' are allowing bias to override fact. Just grabbing onto the 'effect' end of the equation - broken through bolts in this hypothetical example -and trumpeting shrilly that 'here's another one that proves my case' does nobody any good in terms of providing useful information.

 

Obviously it would be preferable if Jab engines were more tolerant of the conditions of use, that is an area that CAMit are seriously working on. Jab engines are built to a weight and a price and you can buy more reliability at a cost of both. That's your choice; and it's fairly obvious that there are plenty of Jab owners and operators who have made that choice, accepted the need to operate and be vigilant about their engine management and are getting good results. It would really, really be useful for Jab owners and operators if these discussions provided more in the way of useful information for them regarding the causes or problems than just the tiresome few lines of condemnation and summary judgement that seem to pervade this forum.

 

As far as RAA/CASA 'doing something' goes - if you want to know what is in fact possible and realistic, ring Darren Barnefield at RAA and ask him. Get the information from the man with the knowledge and responsibility, don't take the drum-banging and dog-whistling on face value. Get the facts, they're all available, it's no great secret conspiracy.

 

 

[biggles]

This is what all should be aiming for ...... ( CHT's bottom RHS ), and that's in degrees Fahrenheit . Admittedly on descent into Southport , but normal cruise temps only slightly higher . Engine No 2200A/2787 , around 2009 , fine finned heads , no head stud re torquing required since new , now around 350 hours . Bob

 

 

 

[DrZoos]

As far as RAA/CASA 'doing something' goes - if you want to know what is in fact possible and realistic, ring Darren Barnefield at RAA and ask him. Get the information from the man with the knowledge and responsibility, don't take the drum-banging and dog-whistling on face value. Get the facts, they're all available, it's no great secret conspiracy.

Its unreasonable to expect everyone to call Darren or for Darren to answer all those calls . So if you have some information that warrants a statement like this, why not put the information here for all to see.

 

 

[kgwilson]

Maybe I should start another thread, but how many have the gull wing deflectors installed on their 3300s? I haven't seen any but Jab still provide the manual (on CD) with the engine but not the components. They also say these should be on the top of the cylinders while one poster said his were on the bottom where you will see them on Lycomings. And the other question, Do they make a difference. I haven't made or fitted them as I think having a good airflow (at least 3.5 times more exhaust area than inlet area) with effective bottom suction and a separate NACA duct and exhaust for the oil cooler should suffice. It is yet to be tested so it is only theory based on research that I am guided by at this stage.

 

 

[Oscar]

Its unreasonable to expect everyone to call Darren or for Darren to answer all those calls . So if you have some information that warrants a statement like this, why not put the information here for all to see.

Well, for those who want certainty in the answer, I'm afraid they'll probably not be satisfied until they have spoken to Darren, but you can certainly start with this: http://www.comlaw.gov.au/Details/F2014C00045/Html/Volume_1#_Toc377559067 - Part 33 is the start of the trail. However to get right down to it in regard to actual certification standards you'd probably need to wade through FAR and EASA stuff as well and get acquainted with the provisions for APMA approval. The current ( I believe) Jab 2200 TCDS is at: http://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCgQFjAA&url=http://www.casa.gov.au/wcmswr/_assets/main/casadata/cota/download/ve501.pdf&ei=NxPjUoHIJYL-iAeh2IGgBA&usg=AFQjCNGIYTkY2lmhqQym2NvHC2ZkM8_ssQ&bvm=bv.59930103,d.aGc&cad=rja

 

I can't seem to locate a TCDS for the 3300 but there must be one.

 

Knowing just what applies in the CASRs is a job for experts, which is why Darren is the best go-to man. Perhaps someone should suggest he might write this up in his column in Sport Pilot if it's a burr under your saddle; I'm quite content with what he told me that the sky is NOT about to fall on my head as a Jab engine owner (little aerial joke there..).

 

 

[Guest Andys@coffs]

Maybe I should start another thread, but how many have the gull wing deflectors installed on their 3300s? I haven't seen any but Jab still provide the manual (on CD) with the engine but not the components. They also say these should be on the top of the cylinders while one poster said his were on the bottom where you will see them on Lycomings. And the other question, Do they make a difference. I haven't made or fitted them as I think having a good airflow (at least 3.5 times more exhaust area than inlet area) with effective bottom suction and a separate NACA duct and exhaust for the oil cooler should suffice. It is yet to be tested so it is only theory based on research that I am guided by at this stage.

Kevin Jab told me to remove them (I think its the AD that adds the lower cowl lip to improve cooling, that says toss them from memory) and Keith Rule also told me to ditch them. If the latest engine installation manual still has them in then this is exactly an example of J providing conflicting info....why isn't the manual updated to reflect the AD?......(assuming it hasn't been)

 

Andy

 

 

[motzartmerv]

Good question Andy. They are generally receptive when you point out inconsistency and errors in the manuals. We have had them change one or two things. Just point it out and they should fix the piblications.

 

:)

 

 

[Guest Andys@coffs]

Yeah found the service bulletin which says remove them. It s here http://jabiru.net.au/Service%20Bulletins/Engine%20files/JSL004-1%20Engine%20Cooling.pdf

 

And the engine installation manual http://www.jabiru.net.au/Manuals/Engine/JEM3302-4_Inst.pdf which says leave them out unless you want them in. If you leave them out then you need larger volumes of air flowing past the cylinders and have to ensure the right pressure differentials.

 

So in this case I was being unfair to J, their installation manual does reflect the AD.

 

Andy

 

 

[Oscar]

This is what all should be aiming for ...... ( CHT's bottom RHS ), and that's in degrees Fahrenheit . Admittedly on descent into Southport , but normal cruise temps only slightly higher . Engine No 2200A/2787 , around 2009 , fine finned heads , no head stud re torquing required since new , now around 350 hours . Bob[ATTACH=full]27021[/ATTACH]

Now THAT is the sort of Plastic Jesus I want on the dashboard of MY plane! I do believe the appropriate term is 'relaxed and comfortable'..

 

 

[Oscar]

Yeah found the service bulletin which says remove them. It s here http://jabiru.net.au/Service Bulletins/Engine files/JSL004-1 Engine Cooling.pdfAnd the engine installation manual http://www.jabiru.net.au/Manuals/Engine/JEM3302-4_Inst.pdf which says leave them out unless you want them in. If you leave them out then you need larger volumes of air flowing past the cylinders and have to ensure the right pressure differentials.

 

So in this case I was being unfair to J, their installation manual does reflect the AD.

 

Andy

Getting the right differential pressure is pretty important (and that's what KG is striving for). Ask any aero engineer what is generally the most tiresome aspect of performance testing for certification purposes and 'cooling' is usually right up there near/at the top of the list. It took something like a year (maybe more) of test, modify, test again to get the J2200 installation on that Motor-Falke working really properly (in combination with lots of inlet tract work to get temps even across all heads) but they persevered and as far as I know it's been a pretty successful installation in the end.

 

 

[motzartmerv]

biggles, those temps look great, and nice and even aswel. Are they as marked? 3 and 4? One of our jabs (170) has always ran very cool in CHT and oil temp. While the 160 has always been a hot engine. CHT's routinely 30 or 40 deg's hotter than the 170, but still within the specs. The hottest engine (j) we have seen was in a 230 a few years ago. Always hot, always pushing the limits of the quoted specs. Pilots needed to fly it very particularly or risk over heating it. It never suffered a breakdown while online with us, but did suffer valve failure some years later when with another school.

 

Just 1 month ago a member bought an LSA 55 and had it delivered to the airfield. After .9 of an hour of flying it too suffered a valve seat failure. Both pilots stated it never got hot and the previous owner stated it was always a cool runner. To be fair, this aeroplane had not done alot of work in the previous year.

 

While I think heat is a contributing factor in some of the problems, I dont think it explains it all. We have several other jab engines we have run for extended periods with our school that have had varying degrees of success and failures. But to date the longest lasting engine is the 170, which has just clocked 900 hours. It snapped a through bolt stud at about 750 hours only 30 hours after the mandatory mod was performed. jabiru copped to that one explaining that the wrong parts were sent and installed. They warranted the damage due to their stuff up. There was simply no way out of it for them as the wrong part was sent and we still had the engine so they couldn't run. But..Im confidant that engine would have made the 1000 hrs. Out of 5 aircraft we have operated (significantly) one of them 'probably' would have made it to top end overhaul. The rest did not.

 

The stats in this poll, while only being 3o or so samples, dont look favourable at all, and certainly my own personal experience with them would align quite closely with the 10% of engines making top end of 1000 with no major problems (indicated in this poll)

 

Small samples such as this are still quite usable when looking purely at stats, although admittedly there are many more not represented. However, 30 samples, spread across a range of users is statistically quite ok to get a general idea of things. Dont hang your hat on them, but certainly dont chuck the results out with the bath water.

 

If this thread proves nothing else, it should serve as a prompt for any potential Buyer to go into the whole thing with eyes wide open. You will most probably, at some stage be spending money on your engine. You may not have to, but at least now you can't say you didnt know it was a 'possibility', some would say a high probability.The mods that 'learned' people speak of certainly do seem to offer a more reliable platform, although, this 'theory' cant be tested in the same way 24 rego'd school aeroplanes (think of taxis) can test the waters.

 

Again, im only commenting on personal experience and the results of this poll, not offering an opinion. (as per my promise) for what its worth.

 

http://www.measuringusability.com/blog/stats-usability-errors.php

 

 

[Bob Llewellyn]

Its unreasonable to expect everyone to call Darren or for Darren to answer all those calls . So if you have some information that warrants a statement like this, why not put the information here for all to see.

Nice idea. RAAus never used to have any enforcment authority, bar suspending maintenance Authorities and Pilot's Certificates. Suspending the Jabiru engineering team's pilot license unless thay upgrade their LSA - self complianced - product would give any magistrate a good laugh. Now, part of the current CASA audit involves a reconsideration of how CASA supports its responsibilities towards RAAus aircraft; so the current official position on RAAus' authority to bully manufacturers is in a state of flux. If you want more background data, read the ICAO Airworthiness Manual; the Morris Report; HORSCOTTS; the Air Navigation Act 1920; the Air Navigation Regulations; the Civil Aviation Act 1988; ANO 95:10; ANO 95:25; CAO 95:55; the Civil Aviation Regulations 1988 et seq; the Civil Aviation Safety Regulations (such as they are); AMROBA's submissions to the current Minister for Aviation; and the upcoming White Paper on Aviation.

Or, for the cutting edge info on the mystery, 'phone the man on the cutting edge - Darren. Alternately, let the man work, and expect much clarification within the next 6 months.

 

 

[motzartmerv]

I like that Bob. Just pop out and read ANA1920 etc.. Just a few pages of light reading for us. :)

 

 

[Bob Llewellyn]

I like that Bob. Just pop out and read ANA1920 etc.. Just a few pages of light reading for us. :)

It's a few thousand words of mindbogglingly boring text, but if you read the entire list, you'll be one-up on the poor overworked crew at CASA... they just get force-fed the latest policy directives... it cures insomnia too, I personally garauntee!

 

 

[motzartmerv]

Yes, im a little familiar with some of those docs, and quite familiar with others..I agree, ZZZZZZZZZZ time. But no mattrer what rule or reg you find, theres always 3 or 4 somewhere else that add ambuguity to the one you just spent 1/2 an hour looking up!!...

 

Your last name rings a bell. Did you have the gazelle aileron mod authority?

 

 

[Bob Llewellyn]

Yes, im a little familiar with some of those docs, and quite familiar with others..I agree, ZZZZZZZZZZ time. But no mattrer what rule or reg you find, theres always 3 or 4 somewhere else that add ambuguity to the one you just spent 1/2 an hour looking up!!...Your last name rings a bell. Did you have the gazelle aileron mod authority?

Dad. I was working with him at the time, we wrote 60 or 80 EOs for Skyfox-y ailerons... turned into a package of paired EOs, one for the root drive production variability (had slim margins), and one for re-mass-balancing.