Cirrus Service Advisory Throws Fuel on G100UL Maintenance Debate

The SA creates a potential dilemma for aircraft maintainers.

Richard Scarbrough

Tuesday, July 16, 2024 at 11:51 AM ET

Verified

Edited By:

Ryan Ewing

GAMI is disputing Cirrus’s claim that use of G100UL voids the warranties on engines supplied by Lycoming and Continental and used in its aircraft. [Credit: Shutterstock]

Key Takeaways:

Cirrus issued a service advisory warning against using FAA-approved G100UL fuel in SR Series aircraft, citing inconclusive material compatibility and potential warranty voidance, creating a dilemma for maintainers.
Aircraft maintainers face a quandary because using the legally approved G100UL fuel contradicts the manufacturer's advisory, complicating the return-to-service process and potentially impacting OEM warranties.
While Cirrus expresses concerns about issues like fuel tank sealant degradation seen in one aircraft, GAMI (G100UL's developer) disputes these claims, asserting the fuel's safety and long-term compatibility, backed by years of FAA testing and STC approval.
The FAA clarifies that manufacturer service advisories are generally advisory for Part 91 operations unless mandated by an Airworthiness Directive, but maintainers must clearly document if maintenance follows OEM guidelines or an alternate, FAA-approved method.

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In June, Cirrus released a service advisory (SA) regarding the use of fuel that had not been approved for SR Series aircraft. This creates a dilemma for many, including aircraft maintainers.

The issue of what is legal (in FAA terms) and approved (by manufacturers) puts maintainers in a sticky situation. On one hand, the FAA issues a supplemental type certificate (STC) allowing for products to deploy on aircraft, but the engine and/or aircraft manufacturer may not approve or recognize the STC as something permitted for use under the terms of their warranty.