In its first interim briefing to the public, the FAA committee charged with recommending a framework for replacing leaded avgas indicated this week that a straight-up drop-in appears increasingly improbable. Both the FAA's Robert Ganley and Michael Kraft of Lycoming engines told a small audience at AOPA Summit on Thursday that an across-the-board replacement for 100LL that won't require at least some downstream changes in the distribution infrastructure looks less likely to happen now than it did a year ago. Although the Unleaded Avgas Transition rulemaking committee (UAT-ARC) isn't charged with actually finding the replacement fuel, but rather recommending a regulatory framework, its deliberations so far have revealed significant enough technical challenges to suggest existing tankage, distribution and transportation may require modifications.
For example, said Kraft, no one's sure about fuel hose compatibility for some of the candidate replacements. "This doesn't show up on an FAA certification plan, but it's a box that has to be checked." Kraft described the challenge of paving the path to a replacement fuel as "not complex," but one requiring many more steps than originally envisioned. In addition to Ganley and Kraft, AOPA's Rob Hackman was also on the reporting panel, but Thursday's briefing was short on details, which all three conceded. No formal or interim draft report will be made publically available. The UAT ARC was chartered by the FAA last January and held its first meeting in March. Thursday's briefing was in lieu of an interim report originally scheduled for AirVenture in July but derailed when Congress delayed the FAA's budget during arguments over the debt limit extension. The committee is supposed to produce by January 2012 a formal framework for finding, certifying and deploying a replacement for 100LL. For more information, listen to this AVweb podcast with Michael Kraft.