Oil giant pulls out of 100LL business

UPDATE: Calls from AOPA and EAA Tuesday morning inform us Ben’s column is incorrect. Exxon-Mobil will continue the manufacture of unbranded 100LL fuel. Exxon-Mobil will discontinue branded fuel sales under the Exxon Avitat flag. We are awaiting confirmation from Exxon’s public relations people.

I recently read that Exxon-Mobil stopped manufacturing and selling 100LL. (I tried to contact them but did not receive a confirmation by press time.) What does this mean for you and your plane?

There are several ways to look at this news. On the business side, it may not be that big of a concern. I know most of you will find this hard to believe, but the leaded avgas business was actually kind of “crowded.” I know that competition makes for lower costs and better service — in theory. However, reality and theory are usually two very different animals.

The problem here is that, compared to the auto gas business, avgas is very, very small — I mean like 0.2 to 0.3 tenths of 1% of the size. Add in the huge liability concerns involved with 100LL and the costs associated with handling a single leaded product that must be segregated from all other fuels and you quickly understand why large oil companies are thinking about getting out of the business.

Most of us look at general aviation as a passion, but when large oil companies look at GA, they only look at the bottom line — and that has not been too good lately.

If the number of companies decreases, the remaining companies will post a better bottom line. This may help them better justify supporting the 100LL business and help them stay in it for a longer time.

I am not going to tell you that this news will reduce the price of 100LL at the pump, because it probably will not. In fact, it may increase the price because of more transportation costs.

My biggest concern is that it will significantly reduce the research on new fuels and the total amount of technical expertise in the piston aviation fuels area. The people at Exxon-Mobil have been among the leaders in aviation piston engine fuels and the ASTM committees that help lead industry research and specification setting. They have done a significant amount of the work that is necessary to ensure that the fuels we buy meet all of the requirements of our aircraft under a very wide array of conditions. If it is true that Exxon-Mobil is getting out of the avgas business and if they pull their technical support from ASTM and other areas, it will leave a very large hole that will not be easily filled.

If you consider that most piston aviation fuel expertise comes from people who start in the much larger auto gasoline arena, you realize there are not many people out there who have worked with leaded fuels. Shell moved its research lab in 1975 and did not build a leading facility at the new lab, so there was never any work on leaded fuels after that. This was more than 36 years ago, which means that the youngest engineer or chemist left in the industry who has ever worked with leaded fuels is probably in their 60s and close to retirement.

I am not saying that young people can’t understand or work on leaded fuels research. But what I am concerned about is that they will not understand all of the problems associated with going to unleaded fuels. For example, I recently read an article about using auto gas in aircraft. One of the statements was that a vast majority of the piston aircraft fleet does not need 100LL at all and can operate on just auto gas. The big problem here is that almost all of the aircraft piston engines out there need to be broken-in on 100LL, then they can be switched over to auto gas. But if they are started on auto gas when new, they will probably have exhaust valve problems. I know this is a small point, but if it is your engine that fails, it will probably be a very expensive point.

 Ben Visser is an aviation fuels and lubricants expert who spent 33 years with Shell Oil. He has been a private pilot since 1985. You can contact him at Visser@GeneralAviationNews.com.


  1. ed says

    I have to disagree with 100LL  being used for breakin.   Back in the day, lead would cause you to do a valve job around 50,000 miles.   The carbon buildup was horrendous.

    My Cherokee has had a diet of unleaded regular for the past 15 yrs. with no engine problems.  

    My higher compression O-320 Glasair has used premium auto gas for the last 100 hrs. with no problems.

    Highest altitude was about 12,000 ‘.

    I lean agressively at low power settings.

    Works for me, your mileage may vary.


  2. Kent Misegades says

    Good article as always, Ben.   In reality, Exxon was a small player in the Avgas business.  Their Avitat brand was not nearly as widespread as the other players.  I do  not know if they also supplied unbranded sells of avgas, might have.  As far as breaking in new autogas-burning engines on avgas is concerned, this is certainly not the case for all the new engines designed for autogas, eg Rotax, Jabiru, ULPower, auto engine conversions, etc.  I understand also that new materials used in valve seats has eliminated this issue from past years, need to check on this.   Best would be to allow free markets to sort this all out and provide us with multiple choices, ie 100LL, 100UL, 94UL, autogas, etc.

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