UL100E AVGAS
VP Racing and LyondellBasell joined forces in 2018 to develop an unleaded aviation gasoline (avgas) in response to the Federal Aviation Administration’s (FAA) invitation for new fuel offerors to enter the Piston Engine Aviation Fuels Initiative (PAFI) program. In late 2023, this collaboration’s latest fuel passed a critical 350-hour durability test in a turbocharged Continental TSIO-550-K piston engine, making it the first unleaded fuel to pass this test and qualify for full-scale testing in the FAA’s rigorous PAFI program. VP and LyondellBasell are concurrently pursuing an American Society of Testing and Materials (ASTM) test fuel specification for the fuel and have completed Phase I of ASTM D7826 materials compatibility testing.
2023 ACHIEVEMENTS
LyondellBasell/VP Racing UL100E fuel completed PAFI qualification testing.
• Materials Compatibility: Subset of full materials compatibility testing involving articles representative of sealants, fuel bladders, and elastomers, performed per FAA mini-MTAC protocol.
• Engine Performance/Fuel Properties: Rated power checks on Lycoming TIO-540-J2BD to compare engine operational parameters and CoA to 100LL.
• Performance & Detonation: Comparative testing between minimum specification 100LL and test fuel performed in altitude test cell on Continental TSIO-520-VB engine.
• Mini-Durability: Engine test to evaluate the deposit forming characteristics and effects of the fuel during a § 33.49 350-hour endurance test on Continental TSIO-550-K engine.
2024 FULL-SCALE TESTING UNDERWAY
- Continental TSIO-520-VB
- Lycoming TIO-540-J2B
- Lycoming IO-540-K1A5
- Continental IO-550-D
- Continental O-470-U
- P&W R-1830 S1C3-G
- (150 Hr. § 33.49 + 200 Hr. flight duty cycles)
- Continental TSIO-550-K
- Lycoming IO-360-C1F
- Air Repair W670-6N
- Lycoming O-360-AIA
- (Engine Handling, Cooling Climb, Hot Fuel)
- Lancair Super Legacy
- Robinson R44 II
- Cirrus SR22T
- Beechcraft G36
- Cessna T206H
- Cessna 402C
- Piper PA-46-350
- Cessna 182Q
- T-6 Harvard IV
- Propeller Vibration
- Cold Starting
- Capacitive Guage
- Metallics (32)
- Non-Metallics (26)
- Finished Parts (5)
- Paint Systems (10)
- Fabric Systems (5)
- Polysulfides (17)
- O-Rings (5)
- Aircraft Hoses (5)
- Distributed Systems (14)
- Fuel Bladders (2)
- Comp. Resins (16)
- Composites (6-18)
- OEM Materials (5) O
- EM Wing Test (4)
OUR PATH FORWARD
KEY POINTS
- EPA issued an endangerment finding for leaded AVGAS in 2023, which would end leaded aviation by 2030.
- VP Racing and LyondellBassel joined efforts to produce a safe, cost-effective fuel that can be widely distributed.
- UL100E is compatible with 100LL in all proportions, with a synergistic octane response.
- Fuel economy is similar to 100LL.
- The anticipated price of UL100E will be on par with 100LL.
- No additional fees to use this fleetwide certified fuel, unlike STC fuels.
- Both PAFI authorization and ASTM specification progress concurrently for UL100E.
- PAFI testing will likely be completed in 2025, after which 100LL phase-out will begin.
- For more information and updates, go to Flyeagle.org
“Our flight testing to date has shown the engine performance is the same between UL100E and 100LL. It is exciting to be testing an unleaded fuel that will comply with ASTM standards, implements the insights gained from the PAFI lessons learned, and shows no perceived difference in the operation of the aircraft. It is a privilege to be working with experienced industry leaders VP Racing and LyondellBasell who have the background and resources to develop, test, produce, and distribute unleaded fuel to the piston powered engines of General Aviation.”
- Andrew Findlay, Test Pilot
For more information about unleaded aviation fuel, visit: www.FlyEagle.org
Frequently Asked Questions
Q: Have you seen any valve seat recession with your fuel?
A: Our fuel showed normal valve seat recession after a 350-hour endurance test in a Continental TSIO-550-K engine.
Q: When will the fuel be available?
A: The FAA is expected to complete testing within the next 18 months. Commercial availability will follow fleet-wide approval, with the rate of deployment dependent on airport readiness to transition from 100LL and the availability of a production fuel ASTM specification.
Q: How does your fuel differ from other unleaded fuel options?
A: Our fuel is distinct in its formulation, and we’ve drafted an ASTM test fuel specification for it. This includes detailed property descriptions and a maximum density specification. This specification and research report were balloted in May and will be re-balloted later this year. The use of our fuel does NOT require an STC – though you will need to have it added to your plane’s placard. Obtaining an STC to use another unleaded fuel could preclude the use of our fleet-wide approved fuel without added modifications and costs.
Q: Can you comment on how the fuel affects maintenance intervals?
A: Our fuel passed a 350-hour durability test in a TSIO-550-K engine without any issues. The test showed no operational issues, with only routine spark plug cleaning at 100 hours. Spark plugs were not cleaned during the last 200 hours. This may allow increased maintenance intervals compared to 100 low-lead (100LL) avgas, saving pilots time and money. Engine oil also showed drastically reduced lead content as the test proceeded with UL100E.
Q: How does the fuel’s performance compare to 100LL?
A: Performance is comparable to 100LL under a variety of operating conditions. Best power & best economy fuel flows are <2% higher than 100LL.
Q: Why did you choose the PAFI program over the STC route?
A: The PAFI program was selected for its transparency and comprehensive testing, fostering collaboration between the FAA, industry stakeholders, and fuel producers. It also aligns with our commitment to developing an industry-approved ASTM specification for the fuel, which is not required under the STC process.
Q: Is the fuel a “drop-in” for 100LL?
A: No unleaded fuel performs identically to FBO 100LL under all conditions in all engines. PAFI testing is designed to identify performance differences between UL100E and 100LL to ensure flight safety for the entire fleet.