Background: Why is unleaded AVGAS needed?
For decades, the general aviation industry AVGAS 100LL is used as the standard fuel, but it has a significant disadvantage: It contains tetraethyl lead, which is used to increase anti-knock properties but is harmful to the environment. Aviation authorities around the world are therefore calling for alternatives that minimise same performance features but are more environmentally friendly.
GAMI's G100UL is one of the first completely lead-free AVGAS products to receive FAA approval (STC - Supplemental Type Certificate). Nevertheless, there are considerable concerns regarding the Long-term compatibility with existing aircraft components.
Test phases and problems: Cirrus identifies material incompatibilities
Cirrus Aircraft is actively involved in the evaluation of alternative fuels and has developed extensive Laboratory tests and flight tests with G100UL. This resulted in Problems with material durability of the fuel systems.
The Tank sealing of aeroplanes of the SR series showed according to Cirrus Significant signs of wearwhen it came into contact with G100UL. These findings were developed in close collaboration with the FAA, GAMI, and the engine manufacturers Continental and Lycoming obtained. The result: the fuel could potentially impair the airworthiness of the aircraft.
Consequences of the Cirrus decision:
- Cirrus currently prohibits the use of G100UL in aeroplanes of the SR series.
- Guarantee and warranty claims expire if operators use G100UL.
- The manufacturers Continental and Lycoming have confirmed that their motors only work with authorised fuels to avoid losing warranty claims.
GAMI itself sees the concerns as exaggerated and points out that G100UL is already Extensive tests has gone through. The manufacturers emphasise that their own tests No negative effects for material compatibility.
What's next? Alternative fuels at a glance
General aviation urgently needs a solution for phasing out leaded AVGAS 100LL. Besides G100UL two other lead-free fuels are currently being tested:
- UL100E from LyondellBasell/VP Racing
- Swift 100R from Swift Fuels
These fuels are covered by the FAA programme EAGLE (Eliminate Aviation Gasoline Lead Emissions) supported. Cirrus itself relies on a comprehensive evaluation process and emphasises that the safety of its aircraft is a top priority. top priority has.
Shell brings 100VLL to Europe - a short-term alternative?
While the complete transition to lead-free fuels will still take time, the Shell Aviation announced that 100VLL (Very Low Lead) from April 2024 will be available at European airports. Cirrus confirms that this fuel can be used in the SR series without any problemsas it does not fulfil the existing ASTM D910 standards for leaded AVGAS corresponds.
Conclusion: A difficult but necessary transition
The discussion about G100UL shows that the switch to unleaded fuel for general aviation Not an easy process is. Manufacturers like Cirrus must ensure that new fuels are not only efficient, but also Compatible with existing aircraft components are. While GAMI continues to work on broad acceptance for G100UL it remains to be seen which unleaded fuel will prevail in the long term.
Source references:
Flieger.News