AOPA says it left its dual-fuel Beech Baron behind in Oshkosh so mechanics can trace the source of some stains that were discovered under the left wing while it was on display at AirVenture last week. 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.
“We have scheduled a mechanic to determine the cause of the leak coming from the left wing of the Baron, which should happen in the next few days,” AOPA Senior VP for Media Kollin Stagnito told AVweb. “We are not yet sure what the substance is, nor where it is coming from.” Word of the stains has been a hot topic on various forums, and speculation is rampant as to their cause.
GAMI Chief Engineer George Braly told AVweb the cause is most likely a faulty or improperly installed fuel cell bladder or patch inside the bladder. He said the bladders in the Baron may be more than 40 years old. He said G100UL has been tested for compatibility with the bladder material and there were no problems. He added that fuel bladder leaks are a relatively common issue with Barons.
