How should aircraft owners prepare for the switchover from 100LL to its replacement? In a previous post, I stated that if — or when — 100LL goes away, the only fuel that will be universally available for general aviation will be one that is chemically very similar to 100LL, but without the lead, and an octane rating of around 94.

If you have a low compression ratio engine qualified on 80/87 or mid-90 octane fuels, you really do not need to change anything. The only concern is that when the engine is overhauled and broken in on straight unleaded fuel, there maybe a problem with exhaust valve recession. If I owned one of these aircraft, I would wait until 100LL is about to go away and then buy a barrel. [Read more...]

Why don’t FBOs sell auto fuel? When will unleaded avgas be available — and who will sell it? These questions, and more, abound about aviation’s Catch 22: FBOs will not stock unleaded fuels until the market supports it — and the market will not develop until the fuels are readily available.

A fuel system at an FBO is an expensive thing to install and maintain. Today, it is necessary for FBOs to offer 100LL, as that is the major demand. If an FBO decides to sell a second grade of avgas, then it would need to install a second (or third, if it handles Jet A) fuel tank, filter, pump and related equipment. With all of the requirements for containment, etc., this is a very costly option — and an option that probably will not pay for itself at this time.

If 100LL goes away, leaving only one grade of unleaded avgas, the FBOs will have no use for a second system. There also is the problem of having multiple systems, which increases the chances of misfueling.

As we look into the future, my best guess is that, if we go unleaded, there will only be one grade of unleaded fuel. It would be nice to have multiple grades, but the general aviation market is just too small to economically support more than one grade of avgas.

So what will happen with the new fuels? Basically nothing.  I do not see a significant shift away from 100LL until the government finally says “no more” [Read more...]

In college, one of my favorite courses was internal combustion engines taught by Prof. Groves. One semester, the main topic of the course was the differences between spark ignition (SI) and compression ignition (CI) engines. After taking the final test, on which we were to compare the advantages of the SI and CI engines, I stopped to talk to Groves, along with several other students. While we were talking in the hall, another student came up and asked, “What does SI and CI stand for?” I remember Groves just hitting his head against the wall and shaking his head.

I feel this way sometimes when someone asks me, “I was working on my plane recently and did not have any aviation grease, so I used some automotive wheel bearing grease. Is that OK?” Unfortunately, people jump to the conclusion that if it does the same job in an automobile as in an airplane, they should be the same. This logic may or may not work — and if it doesn’t, you can have serious problems.

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Today we mourn the passing of a beloved old friend, Common Sense in general aviation.

It will be remembered as having cultivated such valuable lessons as knowing when to not fly into a storm, life isn’t always fair, and maybe it was pilot error. Common Sense lived by simple, sound principals, including “follow the manufacturer’s recommended maintenance practices” and “the pilot is in charge.”

Its health began to deteriorate rapidly when well intentioned but overbearing regulations were set in place. Those who filed lawsuits because engines quit when they ran out of fuel and airplanes actually require maintenance only worsened its condition.

Common Sense lost ground when people moved next to busy airports and then sued because airplanes kept flying near their properties.

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I recently received a letter, “Is global warming debate over?”, from Peter Mortensen criticizing one of my previous columns. I appreciated his letter and he made several valid points. Letters, even critical ones, ensure that we stay centered and help us ensure that what we write is valid and can stand up to scrutiny.

However, I disagree with some of his comments, including when he says “the debate is over,” implying that we should all accept global warming as fact and not question any part of it. I stated very clearly that I did not have a clue as to whether or not there is global warming. But Mr. Mortensen was apparently offended that I would even question some of the data and how it has been analyzed.

I agree that we should protect our environment, but feel that solutions like ethanol do not help the environment. I’ve read several recent studies that show ethanol actually increases total emissions if one takes into account all production, transportation and manufacturing effects. I feel that our only hope to find reasonable solutions to today’s problems is if we have open and informed debate. Unfortunately, most of the debate today is based on profit or political motive, with the facts slanted to show only the sponsor’s view.

In his letter, Mr. Mortensen also noted that we should do everything we can to reduce global warming — just in case it is real. Besides, what could it hurt? This type of logic just blows me away.

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When auto gas was first approved via STC for certain aircraft, there was a lot of support and many airports started to sell auto gas. This was a good deal for many Rotax-powered aircraft, as well as STC’d certified aircraft. But now it is almost impossible to find auto gas on most airports. What happened?

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I’ve received a lot of mail on my recent column on the effects of carbon dioxide on global warming (How are planes affecting the environment?). The replies were both pro and con on global warming and the greenhouse gas thing.

I read most of the reports and find them very interesting. The problem is in the raw data of temperatures in a given area or areas. If one looks at the average temperature over an extended period of time — like for as long as they have been keeping records — the data looks very confusing.

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In a previous column I talked about going to a recent ASTM meeting and the progress being made on unleaded avgas. At this same meeting, there also was a lot of discussions on the qualification of diesel cycle aircraft engines on Jet A.

There were two main areas of discussion: The first was to establish a recommendation on how to certify these engines; while the second was a report that several oil companies are telling their dealers not to sell Jet A to aircraft owners with diesel engines because of liability concerns.

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As all pilots know, you go to Oshkosh to find out what is new in aviation. But if you want to know what’s new in aviation fuels, you go to an ASTM meeting.

ASTM is the organization that is in charge of the specifications for just about everything. If you buy a gallon of Jet A almost anywhere in the world, it will be certified to meet the ASTM D-1655 specification requirements. Likewise, if you buy a gallon of 100LL, the list of tests and the limits that the fuel must meet are defined by the ASTM D-910 specification.

The other part of this is if you have an aircraft that is certified on 100LL specification fuel, you must use only fuel that meets this specification, or use a fuel that has been STC’d for your aircraft.

This means that if a new unleaded fuel is introduced, an ASTM specification must be created to “define” what the new fuel is and what specifications it must meet.

So what is the industry working on?

No surprise, it is working on a specification for a 94 minimum lean rating fuel that looks a lot like the present 100LL fuel, only without the lead.

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