Eleven Year Process Of Engineering, Testing And Validation Culminates Successfully

After a long twelve years, GAMI has achieve something many have tried and all but one have failed to accomplish -- an STC for an unleaded replacement fuel for 100 Low Lead gasoline.

The first application for an STC was filed way back in 2009 and the long process finally culminated in the issuance of STC's SE01966WI and SA01967WI signed by Paul Nguyen, manager of the FAA's Wichita ACO branch on July 23 and received by GAMI on July 27.

Once the fuel begins to be available at FBO's nationwide, you will need to purchase the STC in order to use the fuel on your aircraft. If you already have any quantity of 100LL in your tanks you can mix the G100UL fuel in any percentage. To purchase the STC and use the fuel your engine must be on the AML list for the STC's, by engine or aircraft model. The AML list for the engine will initially target the training fleet of Cessna 172's and/or the Lycoming engines listed below.

• 1E10 -- Lycoming Engines -- IO-360-L2A
• E-274 -- Lycoming Engines -- O-320-D2J
• E-274 -- Lycoming Engines -- O-320-E2D
• E-274 -- Lycoming Engines -- O-320-H2AD
• E-286 -- Lycoming Engines -- O-360-A4M
• E-286 -- Lycoming Engines -- O-360-A4N
• 3A12 -- Textron Aviation Inc. -- 172I
• 3A12 -- Textron Aviation Inc. -- 172K
• 3A12 -- Textron Aviation Inc. -- 172L
• 3A12 -- Textron Aviation Inc. -- 172M
• 3A12 -- Textron Aviation Inc. -- 172N
• 3A12 -- Textron Aviation Inc. -- 172P
• 3A12 -- Textron Aviation Inc. -- 172Q
• 3A12 -- Textron Aviation Inc. -- 172R
• 3A12 -- Textron Aviation Inc. -- 172S

The only modifications required to the engine or aircraft are placards. There is also a short supplement to be added to your AFM or POH. The fuel is initially estimated to cost 60-85 US cents/gallon more than 100LL, but the benefits should more than pay for the additional cost in terms of a cleaner engine and spark plugs and, in the future, the possibility of an increased TBO. There will be no changes to the operation of the engine, except the possibility of small changes in EGT. There will be a slight impact to weight and balance as the G100UL fuel weighs 6.3 lbs as opposed to the 6.0 lbs of 100LL.

Other aircraft and engines will be added to the AML in time as the data from fleet operation with the engine is reviewed by GAMI and the FAA. STC pricing has not been finalized at press time but during a press conference at Airventure 2021 CEO George Braly seemed to agree a $299.99 price for an aircraft in the initial AML list may be reasonably in the ballpark, and in the future a pricing model based on engine type and number of engines might be the way to go.

One issue which seemed unresolved at press time is what would happen to a customer who arrived at an FBO to refuel but could not do so because of a lack of an STC, and would or could not purchase it at that time (e.g. a pilot in a rented aircraft). Braly seemed to suggest that was the pilot's problem, but it seems clear FBOs will likely need to stock both fuels during a transition period if they do not want to lose customers and sales.

FMI: https://gami.com/g100ul/g100ul.php,  https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/EE108314F8FA46F68625871E004CD167?OpenDocument&Highlight=%20sa01967wi
https://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/AD05F8F2FCF0FB188625871E004C5380?OpenDocument&Highlight=%20se01966wi