What You Should Know Before Ordering an Autogas STC*
Autogas airframe STCs are owned/sold by Howard Fuller, president of JTI Air Holdings LLC. (Engine STCs can be purchased from Petersen Aviation Inc.) Use of automotive gasoline (and UL91 fuel for the R44), under the provisions of most of our STCs, is approved by the FAA and by the EASA. The Schweizer 269C-1 STC is approved by the FAA only.
- 1. Important: minimum octane and other requirements
- For Robinson products, the minimum octane is 91 (RON + MON/2).
For Schweizer, the minimum octane is 93.
- All fuels must meet ASTM Specification D-439 for leaded fuel or D-4814 for unleaded. Fuel containing alcohol is not approved, nor is E-85 fuel at this time.
- 2. All Autogas STC applicants must provide:
a. Owner name and address as shown on FAA Registration Certificate
b. Aircraft Manufacturer, Model, Registration Number and Serial Number
c. Engine Model and Serial Number
- 3. The STC is not transferable to another aircraft.
- 4. Installation of an auto fuel STC is an uncomplicated procedure. No major modifications are needed. We provide you with the paperwork and placards required by the FAA to make it all legal. An IA mechanic must "install" the STC by adding the new fuel placards. He then fills out a log book entry and form 337. The whole process takes approximately 30 minutes. No additional modification is required.
- 5. Installing the auto fuel STC does not restrict you to using only auto fuel. Avgas can still be used, and it can be mixed with auto fuel if you wish. Without the STC, you are limited to only avgas.
- 6. We recommend that you purchase fuel only from major manufacturers rather than from cut rate stations. The quality of fuel obtained from major manufacturers is generally superior to that found at less expensive outlets. By using fuel from a major manufacturer you are more likely to obtain fresh fuel as opposed to fuel which was intended for use the previous season.
- 7. It's important that the fuel be fresh because of the Reid Vapor Pressure (RVP). Auto fuel has a RVP of between 7 and 9.3 in summer and it can go as high as 15 in winter. The exact change to the RVP varies from one part of the country to another. Some states have limited maximum RVPs to reduce air pollution and so RVPs have been moving toward lower numbers. Vapor lock is not a common occurrence, but it can develop during hot temperatures if the aircraft has been serviced with winter blend fuel (high RVP). Fuel volatility also affects carb ice. Carb ice can occur more quickly on higher volatility fuel.
* Some of this info is from Petersen Aviation.