LL100 : High Toluene content in our fuel stocks... caution.

[RFguy]

DId anyone read the report of the high Toluene in the LL100 fuel causing trouble in northern australian helicopters ?

 

I have been reading about it the past couple of years with the numerous damaged Lycomings etc,

and lots came to the surface in the latest edition of the magazine FLYING, (which i subscribe to) .

 

Half the lead and in order to maintain the 100 octane, a ton of Toluene added .... Toluene unfortunately is a volatile and thus the LL100 will share unwanted properties with MOGAS....

 

This is quite dangerous I feel for Jabiru (and others) flyers with little tolerance of detonation, because the Toluene is very much a volatile, and the old addage of you can leave LL100 in your tanks for years may now be not the case.

 

glen

 

[NT5224]

19 hours ago, RFguy said:

DId anyone read the report of the high Toluene in the LL100 fuel causing trouble in northern australian helicopters ?

 

I have been reading about it the past couple of years with the numerous damaged Lycomings etc,

and lots came to the surface in the latest edition of the magazine FLYING, (which i subscribe to) .

 

Half the lead and in order to maintain the 100 octane, a ton of Toluene added .... Toluene unfortunately is a volatile and thus the LL100 will share unwanted properties with MOGAS....

 

This is quite dangerous I feel for Jabiru (and others) flyers with little tolerance of detonation, because the Toluene is very much a volatile, and the old addage of you can leave LL100 in your tanks for years may now be not the case.

 

glen

 

Hi Glen

 

Is this just an issue of additional engine wear or could it lead to performance issues in flight? 

 

Cheers 

 

Alan

[RFguy]

this leads to inflight engine failure.

[NT5224]

4 minutes ago, RFguy said:

this leads to inflight engine failure.

Oh dear.

 

Don't want that. Again. 

 

Anyway to test fuel?

 

Alan

[RFguy]

I was going to ask someone for a test for toluene

looks like infra red spectropscophy is a good shot

 

RamanScat.pdf

 

[Thruster88]

From what I have read about the issue of avgas in the Northern Territory it seems to be confined to R22,44 helicopters. There are plenty of fixed wing high performance aircraft like cessna 206,210 turbocharged that are not having the issues. Is it the fuel or is it the type of operations in high ambient temps, dust and hard use etc.

 

https://www.casa.gov.au/about-us/news-article/r22r44-fleet-engine-durability-issues-casa-update

[NT5224]

16 minutes ago, Thruster88 said:

From what I have read about the issue of avgas in the Northern Territory it seems to be confined to R22,44 helicopters. There are plenty of fixed wing high performance aircraft like cessna 206,210 turbocharged that are not having the issues. Is it the fuel or is it the type of operations in high ambient temps, dust and hard use etc.

 

https://www.casa.gov.au/about-us/news-article/r22r44-fleet-engine-durability-issues-casa-update

Unfortunately I live in the Territory and fly behind the same Lycoming 0320 as you find in Robbo 22s. I fuel out of drums the same as  other remote operators...

 

I remember seeing an article on this in Flight Safety  but don't recall the conclusion.

 

Am I doomed? 

 

Alan 

[NT5224]

1 minute ago, NT5224 said:

Unfortunately I live in the Territory and fly behind the same Lycoming 0320 as you find in Robbo 22s. I fuel out of drums the same as  other remote operators...

 

I remember seeing an article on this in Flight Safety  but don't recall the conclusion.

 

Am I doomed? 

 

Alan 

Ok just read the article and am somewhat relieved as it seems to be a long term engine wear issue, rather than bad fuel that can result in sudden  engine failure in flight.

 

Also I appreciate that as a fixed wing, even flying STOL operations over tiger country in the Territory, im not thrashing my Lycoming like those whirly birds which operate at constant high revs.

 

I'll flag this with my LAME at some stage and try not to lose sleep!

 

Cheers

 

Alan 

[RFguy]

Hi Stuart
I think that CASA article completely plays down the issue. 

( I beleive)  there were a small number of in flight failures.

There are lots of maintenance issues. I wouldnt call those faults and problems 'wear  issues' that is engine damage in my book . 

 

I think this is a really big sh1t. it undermines my faith in AVGAS LL100 and undermines my reason for using AVGAS LL100. Low or no volatiles. might as well use MOGAS. almost.....

especially when hot. typical volatile aromatics in aviation gas are < 5%.  mogas 10%-40%... 

this article claimed "17% to 18%" which is pretty high.

 

My thinking is -----the question is how much loss of the aromatics (and thus octane) due to sitting around is an issue for your particular circumstances.

and thus increased protection against detonation, vapour lock etc. 

 

[kgwilson]

The loss of aromatics in 98 petrol does not affect the octane rating in under 6 weeks. In fact the Octane rating increases as the aromatics evaporate off in the first 5 weeks. In the BP study they found the RON octane rating went from 98.1 after 1 week to 99.5 after 5 weeks.

 

Vapour lock is usually only an issue at low barometric pressure of 10,000 feet and above and in a high wing with gravity fed and electric pump supplemented fuel supply it is not an issue at all. The issues that you may have with ageing 98 petrol is starting difficulties and detonation with high revving engines used in boats and small engines such as chain saws etc.

 

A few weeks ago one of out Stihl chainsaws was hard to start and then got hot during use. After shutdown it would not start & there was little compression. The result was a hole in the piston , scored bores and big end bearing failure due to the fuel being about 7 months old. The engine overheated & the 50:1 fuel/oil mix was unable to supply enough lubrication at such a high temperature. Older lower compression 25:1 engines will still run fine on this old fuel. Aero engines are much less susceptible as they are quite low revving except Rotaxes of course.

 

The simple solution is to add some fresh to the tank if the aircraft has been sitting around for a while. You don't even need much. My 3300A engine started easily after sitting for more than a month with about 40 litres in a 100 litre tank and no topup. I flew for an hour and it ran perfectly.

 

There are 2 reasons to put Avgas in a Jabiru engine if you can't get 95 or 98 petrol. 1. Avgas is in the bowser on the airfield and 2 the aromatics make 95/98 petrol stink. The advantages are price, no poisonous TEL and a cleaner engine. I have only ever used Avgas when away at an airfield as that was all I could get.

 

Have a look at the BP study of fuel storage in vehicle tanks attached.

petrol-life-vehicle-tanks.pdf

[Thruster88]

1 hour ago, RFguy said:

Hi Stuart
I think that CASA article completely plays down the issue. 

( I beleive)  there were a small number of in flight failures.

There are lots of maintenance issues. I wouldnt call those faults and problems 'wear  issues' that is engine damage in my book . 

 

I think this is a really big sh1t. it undermines my faith in AVGAS LL100 and undermines my reason for using AVGAS LL100. Low or no volatiles. might as well use MOGAS. almost.....

especially when hot. typical volatile aromatics in aviation gas are < 5%.  mogas 10%-40%... 

this article claimed "17% to 18%" which is pretty high.

 

My thinking is -----the question is how much loss of the aromatics (and thus octane) due to sitting around is an issue for your particular circumstances.

and thus increased protection against detonation, vapour lock etc. 

 

Hi Glen, the change to avgas in about 2015 appears to have had little effect on the lycoming fleet. Failures due to fuel, I am not seeing it.

 

https://www.atsb.gov.au/publications/2018/ar-2018-058/

[RFguy]

Hi STuart

that's not how I have read it

 

There has been a change to the 100LL blend . 100LL original had around 5% aromatics. this blend 17=18.

 

(not about use of 100/130 instead of 100LL in northern australia).

Edited November 22, 2021 by RFguy