Stains Reported on Wing of AOPA Aircraft Fueled by GAMI G100UL

The Beech Baron is being used as a test bed to compare the performance of GAMI G100UL unleaded avgas with 100LL.

Russ Niles

Wednesday, July 31, 2024 at 02:32 PM ET

Verified

Edited By:

Travis Tingle

[Courtesy: AVweb]

Key Takeaways:

AOPA's Beech Baron, used to test GAMI G100UL unleaded avgas, was left in Oshkosh for mechanics to investigate unexplained stains found under its left wing.
The stains are on the wing containing G100UL, but AOPA has not yet confirmed their substance, origin, or if they are fuel-related.
GAMI's chief engineer suggests the stains are likely from a common issue with old Baron fuel cell bladders and reiterates G100UL's compatibility with bladder materials.

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The Aircraft Owners and Pilots Association (AOPA) says it left its dual-fuel Beech Baron behind in Oshkosh, Wisconsin, so mechanics can trace the source of some stains that were discovered under the left wing while it was on display at EAA AirVenture.

The Baron is being used as a test bed to compare the performance of General Aviation Modifications Inc.’s (GAMI’s) G100UL unleaded avgas with 100LL. The stains are on the wing with the tank holding G100UL, but it has not been determined that they came from the fuel.