Textron says it won’t add G100UL unleaded avgas to its approved fuel list until it has been more thoroughly tested. In statements released last Friday (one for singles, one for twins), the company said it won’t be giving its stamp of approval to the fuel unless and until that more comprehensive testing has been done. It cites the Piston Aviation Fuel Initiative (PAFI) and the Eliminate Aviation Gasoline Lead Emissions (EAGLE) fuel evaluation process, of which it is an active participant, as the kind of “comprehensive testing of candidate replacement fuels for engine performance, materials compatibility, and operational safety” it’s looking for.
G100UL has an STC certifying its use in all piston engines powering certified airplanes on the FAA registry. It is also certified for use in all piston helicopter engines but not the airframes. That certification was expected earlier this year but hasn’t been approved by the FAA. It affects about 3,000 helicopters. Swift Fuels has also received a limited STC for two models of Textron Cessna 172s for its 100R fuel but Swift was not mentioned by name in the statements. GAMI has responded to our request for comment and says it is analyzing the statements and will issue a statement in due course. Swift has not responded to our request for comment.
The full statements are copied below but the salient parts are as follows:
“Because the STC process, unlike the PAFI andEAGLE programs, does not involve broad aviation industry coalition participation, neitherTextron Aviation nor its engine suppliers, Lycoming and Continental Motors, have had theopportunity to conduct the type of comprehensive and wide-ranging performance, compatibilityand operational testing with respect to that fuel needed to provide a basis for approval of thefuel for use in Textron Aviation’s current and legacy fleet of Cessna and Beechcraft aircraft.”
“The continued airworthiness and operational safety of our products and their reliable service toour customers and their passengers is of paramount importance to Textron Aviation. For these reasons, Textron Aviation has not yet approved G100UL for use in its piston engine products. Such approval can only be made by Textron Aviation if the fuel is approved by its engine suppliers and has also undergone testing to confirm its airframe fuel systems performance,compatibility, and operational safety.”
Textron also says it is aware of reports that “two different OEMs have been advised of reported issues with fuel tank sealant degradation following exposure of those sealants to G100UL.” It did not specify the nature of those issues and AVweb is aware of three tank issues that have been tied to the use of G100UL. One was on the AOPA Beech Baron fuel test aircraft last summer which was determined to be caused by a leaking patch on a 46-year-old fuel bladder and had nothing to do with the fuel. More recently a couple of Mooney owners have reported fuel seepage issues after switching to G100UL. In one case it was a new leak and in another it involved paint damage on tanks that were already seeping. Neither of those have been definitively blamed on G100UL and hundreds of other aircraft are using the fuel apparently without issues. Here are the full statements from Textron:
