In a letter to members of the Malibu-Mirage Owners and Pilots Association, the group’s president, Jonathan Sisk, said this week that the FAA’s just-made-public 100LL replacement plan deserves a critical eye. Although he says it represents progress, he believes it’s too narrowly focused on just one path. “I also recommend that Clean 100 members not buy into the notion that the ARC recommended-process is the exclusive means to arrive at the best solution. That is absolutely unknown by anyone,” Sisk said in his letter. Clean 100 Octane Coalition is the owner group that formed two years ago when the 100LL replacement issue got pushed to the front burner. Sisk was a member of the original Unleaded Avgas Transition Aviation Rulemaking Committee that formed in early 2011. The summary of the report is here (PDF). The full report is here (large PDF) and the appendices are here (PDF).
From its earliest work, Sisk said, the committee had a strong bias in favor of only ASTM-developed standards as a means of fuel development and against a dual equivalent track using the STC process. “We, as an industry, still need to fully explore and the FAA to fully support both the collective-consensus approach described in the ARC report with PAFI and Avgas Readiness Levels (ARLs), as well as those of independent fuel innovators who prefer to tackle these same issues and demonstrate regulatory compliance for specific engine/airframe approvals through the existing Supplemental Type Certificate process. Each has its advantages. I believe the ARC is better suited to managing the fallout from a less capable fuel, and the STC process quicker and more efficient for qualifying a more capable fuel with less impact on the existing fleet.” Only one company has thus far pursued wide fuel approvals via STC, General Aviation Modifications Inc., with its G100UL. But the FAA’s Engine and Propeller Directorate has resisted this approval process at every stage to the point that FAA management had insisted on involvement of fuel experts from outside the directorate. GAMI’s STC project is moving forward, but at a slow pace. In his letter to MMOPA members, Sisk said “there are those at the highest levels of the FAA that simultaneously support both the ARC and STC paths. They are deserving of our gratitude for their courage in leadership.” Sisk said the work of UAT-ARC is deserving of support and its taxpayer-funded centralized FAA testing may yet attract innovative solution. But he also noted that “it’s prudent to let both the ARC and STC paths play without obstruction, interference or favor. Over time, it will become apparent which ends up better serving the interests of general aviation and high performance piston operators.”