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G109 B owners, My G109B is in the shop undergoing an annual. The elevator control rod (AD 2012-26-09) has been inspected and is ready to be re-assembled. Before the assembly is riveted and re-installed, I am taking the opportunity to explore a Form 337 substitution. I purchased a 1†diameter, solid, 6061 T2 aluminum rod from Airparts here in Kansas City to replace the 20 mm thin wall tubing used in the original Grob assembly. I had two options to buy the aluminum rod locally, both options cost only $24! The ends of the rod only need to be bored a little over an inch deep to accept the existing end fittings (yoke and quick release). The mass balance portion of the fork end fitting will be removed. The resulting assembly will weigh within approximately an ounce (2%) of the original assembly and in all structural measures be simultaneously more robust. If this method is approved, it will be an inexpensive solution for those G109B’s that might otherwise require replacement of the thin wall tubing. Grob’s response, on asking them to supply original tubing, was that owners with issues should send the entire assembly to Grob and they would rebuild or replace the unit. Based on the AD verbage, I surmise that cost would be $680. If my FSDO accepts my Form 337, my proposed substitution will cost approximately $30. This may be premature, but I thought it might be useful information for you. Stu