Problem with my J230, Flight Safety implications

[Guest Andys@coffs]

Hi Guys

 

Today, as part of a pre-flight activity on my Jabiru J230 I came across a problem that, to me, had flight safety implications, and as such I will be submitting a report to RAAus shortly, however wanted to bring your attention to the problem asap.

 

On entering the cockpit I identified that there was a smell of fuel which was more than normal. After looking around I identified that the internal carpet lining around the wing fuel gauges was wet with fuel and that in a number of places the blue die in the fuel had dried to a significant trace.

 

The bottom line is that the hose clamps that were used to clamp the fuel line to the fuel gauge at the bottom was fully tightened, to the point that no more turns of the tightening screw were available, yet the clamp was able to be moved, under finger pressure around the hose. The looseness was allowing capillary leakage of the fuel to wick down the fibreglass body, onto both the outside of the Aircraft and the inside onto the fabric lining. This was occurring with significant leakage on the passenger side, where the lining was wet for a radius of 7-10cm around the gauge and on the pilots side to a radius of 2-3cm.

 

The attached photo shows the area (passenger side) and the style of clamps used. The fuel piping is the blue plastic type that is around 9mm in outside diameter. The attached photo was taken on the 17th of February this year and shows no sign of leakage. No work around the gauges has occurred since that time. On removing the original clamps it became clear that the clamps originally worked, however not ideally in that they were at the end of travel, however over time the fuel hose has compressed allowing the clamps to become ineffective.

 

I have replaced some of the clamps with the worm driven hose clamps that we are all used to, however I note that they have the potential to cut the fuel line with the worm drive slots on the bands. Tomorrow I’ll be looking at the remainder, however I already note from the photo that some of the other clamps that can be seen are also at full closure suggesting that they too need to be replaced. The particular clamps that most needed to be replaced cant be seen in the photo, indeed they can only be accessed when the fibreglass flashing on top and bottom of wing where the wing joins the fuselage is removed.

 

Can I ask that you other Jabiru drivers have a look at the clamps on you aircraft to ensure that you aren’t shortly to have the same problem. In my case the fuel piping where the problem occured is used extensively as are the clamps that were effectively too big for the job, as such the checking that I will do goes from the wing tanks right through to the carbbie and all points in between.

 

Regards

 

Andy

 

[ATTACH]2007[/ATTACH]

 

 

 

[Yenn]

This raises 2 points.

 

1 A friend of mine who has built several Jabiru's used to put a sleeve around the hose under the clamp. i believe he used another piece of hose.

 

2 Several years ago I replaced most of the fuel hoses on my Thruster as a precautionary measure. I used the you beaut blue fuel hose and 18 hours later I had a new fuel hose break at the feed into a carburettor. At the time I was travelling in company with a lightwing and told him of my problem and landed in a paddock. My friend could not find me even though I could easily see him. A helicopter pilot who heard my call kept in touch until I reported safe on the ground.

 

The above incident was reported to the AUF as it was then, but it was never mentioned in the magazine.

 

I have steered well clear of plastic fuel lines now.

 

I replaced the broken fuel line with the gearbox breather hose and continued to Old Station where I did a complete change of fuel lines and found the line from the tank to filter broke as soon as I touched it.

 

I was lucky to be able to land with some power rather than a complete stoppage.

 

 

[Admin]

Well Done Andy!!!

 

 

[Thruster87]

How long had the blue fuel line been on the Thruster? prior to deterioration and was or is the a/c stored in the open or in a hangar. Really need to be watchful of these and any other hoses/lines cheers

 

 

[Ross]

Hi Andy

 

I have noted the same thing with my J160 kit (yet to fly) which has the blue fuel lines. The hoses can be turned on the fittings when the clamps have been tightened to as far as they will go.

 

So far I have not done anything about it.

 

If (when) the NSW Government legislates (as stated in a news item a couple of days ago) to make it compulsory for all petrol in NSW to have a compulsory ethanol component

 

the hose clamps may not be our only problem!

 

Regards

 

 

[Guest J430]

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[Ultralights]

what about MOGAS in 2 stroke engines?

 

from what i hears it must be Mogas as it has no lead.

 

 

[Guest Andys@coffs]

MoGas / AvGAs

 

A couple of points:-

 

I suspect that the die that is added to AvGas is higher in quatity than MoGas, as such when it dries on a surface there is no doubt that it was there. (Benefit 1)

 

The smell of AvGas is not something you can ignore, there must be some sort of additive that makes it more noticable to me than MoGas. Not that I want people to think Im a petrol sniffer, cause Im not, however the smell of AvGas makes me feel sick MoGas doesnt have the same observable result for me (benefit 2)

 

With MoGas there are tests you can do to find out if alcohol is added. The reason for doing the test is simple, without the test you dont know if it does or doesnt contain alcohol, in the same way that you dont know if some greedy service station owner has added some other cheaper than fuel hydrocarbon to try and lift his profit margin, nor can you easily test for those. Of course AvGAs is a known product with a much more traceable supply chain. When the additional costs are compared to the cost of your chariot MoGas to me would seem to be just a means to save a few $ with an associated risk that doesnt reflect the size of the savings. that is the additional risk you take on far outweighs the few dollars saved. (benefit 3).

 

Lastly, if the manufacturer of the engine and or aeroplane makes a very strong recommendation that you dont use MoGas then I would suggest that any warranty work you need from them would likely be much more difficult to arrange if you then chose to go against the manufacturers recommendations.

 

Regards

 

Andy

 

 

[Captain]

Andy

 

Good topic and great post.

 

Like Ross, I am not yet flying my build, but I have to say that I have never liked the look of those blue plastic lines, nor the Manual's requirement to replace them all every 2 years.

 

I have upgraded to thicker solid black pressure rated (but not EFI rated) fuel lines similar to those supplied by Jabiru with the engine between the mechanical fuel pump & the carby.

 

From your post it looks like I did the right thing.

 

They are larger OD and turn corners via a bigger radius which makes them a bit more difficult to install in some places but they look to be much higher quality & longer lasting. Am not even using the blue ones for the head tank vent lines.

 

Regards Geoff

 

 

[Yenn]

How long had the blue fuel line been on the Thruster?

 

They had been in the plane 5 months and it was stored in an open hangar.

 

The replacement was US Coastguard approved thick rubber lines and they gave no trouble. I sold the plane about 9 months after the replacement so would have been surprised to have any problems. The Corby is fitted with the same type of fuel lines which have been replaced once during 5 years as a precaution.

 

 

[bushpilot]

Andy's report prompts me to tell of my experience this past week:

 

My Airborne trike (Redback) has done just 52 hours TTIS - but over a period of 3 years.

 

I pre-flight check it every flight (as you should..) and had not noticed the deterioration of the rubber fuel lines (approved fuel line material to some USA standard) - until a friend visited our farm, and he is into large scale model aeroplanes; he walked up to the engine and straight away said "when are you going to replace those fuel hoses?" I looked closely and couldn't believe how many fractures were in all of them. I took them off and when they were bent a little, some of the fractures opened right up and you could see the linen separator between the 2 layers of rubber.

 

This trike has been hangared or garaged all its life and has an engine cover placed on it after each flight. No UV and no excessive heat. I cant see how top grade material like that could deteriorate so quickly - in these conditions.

 

Also taught me that a fresh pair of eyes from time to time is one of the best annexures to self pre-flighting...

 

Cheers,

 

Chris

 

 

[Guest Rocko]

Fuel line quality

 

Hiya all

 

When building my Hanuman, I discarded the supplied fuel hoses in favour of some apparently decent, high quality fuel hose sourced from a reputable truck wholesaler (since most auto wholesalers sell cheap crap). When I began having issues with the fuel tank (another story), I used a short piece of this hose to extend the fuel pump and more quickly drain the tank, since the gel from the dissolving fuel tank had blocked the original hoses, and they wouldn't flow.

 

This hose was sitting with the end soaking in fuel in the jerry can for about 30 minutes. When I pulled it out, the entire outer sleeve of the fuel hose had melted to a rubbery mess, separated from the reinforcing mesh, and even the inner sleeve had started dissolving.

 

After just 30 minutes soaking in fuel!

 

Needless to say, we dumped all that hose, and replaced it with high quality Goodyear branded product. I've had no problems since.

 

I now watch my hoses VERY carefully, and I trust none of them.

 

Cheers,

 

Scotty

 

 

[Guest Rocko]

Additional...

 

Mind you, I did find a good use for all that blue plastic fuel hose I had lying around.

 

Makes a nice static and pitot hose ;>

 

Scotty

 

 

[Ben Longden]

Avgas is going to be the preferred option, not only due to its more stringent quality checks, but with the increasing use of ethanol in various MOGAS brews, and the issues with ethanol and fuel distribution lines, filters and seals.

 

Anyone know what Rotax advises for their engines?

 

Oh, and I would love it if someone can tell me why the smell of Avgas makes me nauseous...

 

Ben

 

 

[Bernie]

In 2011 there will be no more avgas as all leaded fuels will be outlawed world wide

 

 

[BigPete]

Hmmmmm -

 

that gives me just 4 years to wear out the Jabby!!

 

rubber bands anybody??

 

regards

 

 

[Guest brentc]

Don't worry, you can still run your Jab on premium or 95+ ron.

 

 

[Guest ozzie]

The smell of avgas and other fuels is from the type of aromatics and cracking agents used, there not good for you and the higher the rating the worse it smells. i am not a chemist but sorta understand the process of making fuels. i think that is how it is spelt.

 

the smell of burnt avgas reminds me of jumping from cessnas

 

 

[BigPete]

Don't worry, you can still run your Jab on premium or 95+ ron.

That's provided it is ethanol free!!!

 

regards