100 unleaded = potential disaster?

[HiFlite]

The recent news of a certified unleaded replacement (now only by STC) for 100LL has the GA world abuzz. Odds are pretty high that a 100UL will be replacing 100LL sooner rather than later. However, this could present a big problem for Ximango owners and others airplanes produced in small volume or for those whose manufacturers are now defunct. Many will run just fine on UL100 or 94UL or mogas, but specify only 100LL on their original airworthiness certificate and are hence only legal to fly with 100LL. Presently, if I understand it correctly, this can only be changed upon petition and proof from the airframe manufacturer. (Approval by the engine manufacturer alone is not sufficient.) Even if the original manufacturer exists (and some, Aeromot, just barely), what motivation do they have to make such an effort - one that earns them nothing? Going the STC route is not a much better alternative when the sales potential may only number in the dozens.

Hopefully, the FAA will declare UL100 or whatever as a functional and legal replacement for 100LL without the potential paperwork nightmare which will otherwise follow. Or potentially worse, the grounding of hundreds of perfectly good airplanes, including ours.

While this forum seems about dead, consideration should be given to banding together to get the appropriate STCs needed to keep 'em (legally) flying. Opinions?

[Thermalseeker]

If you're flying behind a Rotax the MANUFACTURER recommends unleaded fuel. You can run 100LL in a 9xx, but you're oil change interval is cut in half and you run the very real risk of destroying your engine. Rotax recommends that you use lead scavenging additives in your oil (that aren't FAA approved). Considering Rotax warns that the improper use of 100LL resulting in lead build up inside the engine can cause catastrophic engine failure in Rotax 9xx, if the FAA (or an insurance underwriter) wants to argue what is on the Type Certificate vs. manufacturer recommendations I will accept that battle. Until then, I will continue to run UL93 in my Certified 912s at my discretion as I see fit.