Originally published at: https://avweb.com/aviation-news/boulder-airport-sets-timeline-for-phasing-out-leaded-avgas/
Boulder Municipal Airport could begin offering unleaded aviation fuel by late 2026, part of a state-mandated plan to phase out leaded avgas by 2030.
Overheating issues during summer flights… what a surprise! Well get ready for the destroyed exhaust valve guides, the badly damaged exhaust valves, the excessive carbon buildup on the backside of the inlet valves and the thousands of premature cylinder failures. Oh’ also get ready for the inflight catastrophic engine failures and the odd funeral or more. It’s all coming your way. You should have listened to the vast experience of other parts of the world when they introduced a leaded avgas variant which slowed the combustion process and drastically altered the heat flux in the combustion cycle. You won’t often see it in a dyno or in a test cell, but you’ll sure as hell see the results in actual real world conditions in hot, and especially in hot and humid conditions. But then again the ‘experts’ doing all this know too much to listen to several hundred thousand hours of actual in flight experience and data… so on your merry arrogant ways 
Scandinavia has been using unleaded avgas for decades; Engines are lasting longer more reliably. Lead causes exhaust valve problems, particularly on Lycomings. I have flown hundreds of hours on Mogas in a Cessna; no problems; no “morning sickness” sticking valves, longer cylinder life. A glider operation switched to Mogas; hard service for engines. Cylinder life doubled. Lead is not good for engines or people. Kudos to Colorado.
There is also the GAMI product. Why is it none of these “news” outlets talk about it anymore? In this case - they just print the press release. And the big players in the fuel industry have banded together to make sure no one talks about this upstart competitor. The EAA sold out - you never see G100UL mentioned in communications from them (like their magazine). Guess they were worried about support money. It works, and it works now. All the “no lead” benefits are there. 100% of piston engine fixed wing aircraft are approved via STC. You can mix it with 100LL. The problem? Money - and who gets it.
The GAMI product has a pretty big known deficiency: it eats certain rubber products. Good long youtube video here, which also explains why some airplane owners have reported a strong fuel odor smell in the cabin of their airplane after switching from 100LL to G100UL: https://www.youtube.com/watch?v=bqFZbtR4pRc
Swift’s 100R was also tested. It behaves like current 100LL in terms of material compatibility, at least those tested.
Personally I won’t be putting G100UL in my airplane and risk degradation of the rubber hoses and polysulfide tank sealant, let alone cosmetic damage to the paint around my fuel tanks. Of course, my engine is also MoGas compatible (engine, not sure about pumps etc. and their seals, ethanol compatibility etc.), and experimental, so I have more options than most.
Both the benefits and the risks have been apparent in the auto industry for decades now, and the automotive engineers have managed the risks pretty well. The benefits are clear. Longer spark plug life, longer valve train life, lower exhaust emissions generally, especially when combined with electronic engine controls, and the clear health benefits associated with eliminating lead from exhaust emissions. The risks involved lower octane, at least initially, and ethanol in gasoline hasn’t been an entirely happy marriage, with the same issues of flexible parts made from either natural or synthetic rubber deteriorating when exposed to ethanol.
The big difference between the automotive experience and the aviation story continues to be the demand for “backward compatibility”, an issue that our automotive brethren never had to experience, fortunately. If the petroleum engineers and the aircraft engine designers can put their heads together, I’m sure that any lingering issues can be addressed satisfactorily, but it will take time, and time is the one thing that is in short supply in this soap opera! If the auto folks can build engines that make 800 hp on stock unleaded pump gasoline and that have a full factory warranty, what is stopping the aviation sector from accomplishing the same objective? I hate to say it, but money seems to be the big stumbling block. If the aviation industry had followed the dual-fuel path taken by the auto industry and eliminated the backwards compatibility requirement thirty (30) years ago, we wouldn’t be having this discussion now, because we’d be done with this by now, and leaded gasoline would have been consigned to the ash heap of history, where it belongs!
Somewhat amusing… there are big differences between the engines that you either intentionally ignored or just don’t understand the implications of at all… and btw, there have been many clever people throwing tens of millions of dollars at this issue for over 20 years.
There is no easy answer for a drop in replacement that covers especially the more difficult engines - which happen to be the vast majority that aren’t fitted into training or ‘toy’ private planes. Most of the commercial activity occurs with the ‘difficult’ engines. Despite the parochial attitudes of many people in the USA, you need to understand that any solution must be global since the fleet is global and the source of the engines is the USA. No global solution = no actual solution. This means that ETBE and MTBE cannot be part of the fuel as that is banned in some countries with huge GA fleets. One which has already seen the disaster of messing with high aromatic hydrocarbon levels (btw.. this is also a feature of most UL formulations) in hot and humid climates. This fuel led to in excess of 4000 extremely premature cylinder failures in a 6-7 year period in a fleet which in the previous 30 years (prior to messing with the fuel composition) had virtually zero cylinders fail to make TBO. Many failures were within 200-300 hours from either overhaul or brand new cylinder from the manufacturer. People are kidding themselves if they think that this kind of data isn’t going to emerge in other parts of the world when real world operation on these ‘experimental fuels’ becomes widespread across challenging engines/climatic combination of circumstances.
That is all true, but how does that affect the method used to make the change? By offering both leaded and unleaded fuels during a transition period, you keep existing engines in service until normal wear gradually removes them from service, while new airplanes are designed from the start to accept unleaded fuel. BTW, the same argument could have been made with automobiles, as the European Union began to adopt emissions standards about five (5) years after the US EPA began regulating automotive tailpipe emissions in the US. The US EPA gave all automakers five years to engineer their engines to accept unleaded gasoline, a similar phase-in period might work for aviation. To this day, variations in both emissions and safety standards force worldwide automakers to tailor cars for different markets, so that is not an insurmountable difficulty. Again, the Asian and European manufacturers were late to the party, the EPA and NHTSA got there first, but now all of the major auto producing countries have to comply with multiple standards worldwide!
Yes, this makes cars more expensive, but it’s not an insolvable problem. A harmonized worldwide standard for both safety and emissions technology would certainly make things easier for both car and airplane builders, but the odds of that happening soon are somewhere between slim and none. Each government agency adopts the same basic attitude. Just adopt our rules and everything will be fine! Since no Government Agency wants to give up any power, no one will concede, so it becomes a big staring contest, and nothing happens! The four (4) major car building entities, the USA, EU, Japan and South Korea all have different rules, and now with Red China getting into the car business in a big way, that’s just one more set of rules to follow! I would very much prefer a worldwide, harmonized standard for airplane fuel, but like the auto story, none of the bureaucrats will make the first move!
What about the cost of unleaded avgas, the likely need for installation of new tanks at airports, etc.?
This topic was automatically closed after 7 days. New replies are no longer allowed.