Timeline of leaded aviation fuel

By Robert Taylor, Researcher for The LEAD Group Inc, Australia, 23rd December 2011

1921 - TEL (Tetra-ethyl lead) added as an anti-knock agent to gasoline by Thomas Midgely.

1922 - Army experiments with TEL in airplane fuel but does not adopt it.

1923 - Leaded gasoline (blended at a petrol refinery) for automobiles sold.

1926 - US navy successfully experiments with adding TEL directly to fuel.

1930 - US army certifies fuel with up to 3ml/gallon of TEL additive.

1934 - British aviation fuel standards allow up to 4 ml/imperial gallon of TEL.

1939 - First jet powered aircraft flight. Jet fuel does not contain lead.

1937 - Ten of fourteen types of aviation gasoline in the USA contain TEL. Unleaded fuel is only used in low-performance engines but most fuel is still unleaded.

1942 - Introduction of super-chargers increases the importance of TEL. Super-charged planes use a minimum 100/130 grade gasoline which contains up to 3 ml/gallon while higher performance super-charged planes use 130/145 grade which contains up to 8 ml/gallon.

1947 - US ASTMD910 aviation fuel standard for piston engined aircraft first applies. The standard only permits the absence of TEL in low-performance fuel. Majority of low performance fuel unleaded.

1954 - Majority of low performance US fuel contains TEL.

1970 - US passes Clean Air Act.

1971 - Introduction of 100LL (low lead) aviation gasoline with a limit of 2 ml/gallon of TEL. Quickly becomes dominant fuel type due to similarity to 100/130 grade.

1981 - Hjelmco oil releases unleaded aviation gasoline that can be used in low-performance aircraft after a break-in period using 100LL. It is only certified for use in Europe and Japan.

1993 - Ethyl Corporation ends manufacture of lead anti-knock compounds with the closure of its Canadian plant; instead markets additives purchased from the Associated Octel Company Limited (later renamed “Innospec”), the world’s only remaining producer of AvTEL (TEL for aviation fuel).

1995 - Ban on use of leaded gasoline in automobiles in USA.

1998 - Unleaded 82 UL (unleaded) is approved for some low performance aircraft. But it is unsuitable for high performance aircraft which consume the bulk of leaded fuel.

2006 - US NGO Friends of the Earth petitions US EPA over aircraft lead emissions.

2008 - EPA lowers air standard for lead from 1.5 to 0.15 micrograms per cubic meter.

2011 - Friends of the Earth announce they will sue the EPA over aircraft lead emissions. Plans announced to develop 100 VLL (very low lead), with a lower level of TEL than 100LL. US company Swift Fuel obtains US certification for UL102, an unleaded fuel suitable for higher performance aircraft. As of 2011, however, no unleaded fuel is certified for all aircraft using 100LL.

Suggested Reading

AOPA (Aircraft Owners and Pilots Association) “Issues related to Lead in Avgas” AOPA online http://www.aopa.org/whatsnew/regulatory/reglead.html

Desrosier, Walter & France, Mike (2011) “Beyond 100LL: Next Steps in Addressing Leaded Aviation Gasoline” 2011 ACI-NA Environmental Affairs Conference June 27, 2011

http://www.aci-na.org/static/conferences/enviro%202011/Monday/W.%20Derosier%20-
%20Leaded-Avgas-Next-Steps-2011.pdf

Ells, Steve (2011) “Avgas Alternatives” Flying Feb 15, http://www.flyingmag.com/aircraft/modifications-maintenance/avgas-alternatives?page=0,0

Epstein, Curt “EPA begins ruling process to phase out leaded avgas” AIN [Aviation International News] Online September 2010 http://www.ainonline.com/?q=aviation-news/aviation-international-news/2010-08-27/epa-begins
-ruling-process-phase-out-leaded-avgas

Ziulkowski, Jonathon David (2011) “Collective Knowledge on Aviation Gasolines” Perdue University Report/Thesis http://docs.lib.purdue.edu/techdirproj/43/