Service Letter No. 185 B

The Use of Higher Octane Aviation Fuel, 100LL Blue or 100 Green, for Engines Rated for 80/87 Octane Fuel


Supersedes Service Letter No. L185 A

January 19, 1988

Models Affected

To all Owners and Operators of Textron Lycoming Aircraft Engines

We received many inquiries from the field expressing concern over the limited availability of 80/87 grade fuel and associated questions from use of higher leaded fuel in engines rated for grade 80/87 fuel. The leading fuel suppliers indicate that in some areas 80/87 grade aviation fuel is not available. It is further indicated that the trend is toward phase out of 80/87 aviation grade fuel. The low lead 100 LL Avgas, blue color, which is limited to 2ml tetraethyl lead per gallon and the higher 100 aviation fuel, color green, with a maximum of 4.0ml tetraethyl lead per gallon are available. Whenever 80/87 is not available you should use the lowest lead 100 grade fuel available. Automotive fuels should never be used as a substitute for aviation fuel in aircraft engines.

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