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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

Noseplate and Elevator Push/Pull Tube Inspection AD’s Robert Mudd made up and sent me an epoxy kit that allowed me to add a 5/8†diameter (16 mm) inspection hole in the vertical stabilizer, precisely per Grob specifications, with absolutely minimal fuss. The kit included the specified resin, catalyst, and flocking, and… rubber gloves, a mixing spatula, and complete instructions. The epoxy resin and catalyst arrived pre-measured. It was only necessary to mix the resin and catalyst, add the cotton flocking to the designated consistency, and apply the mixture. No measuring! The Kit provided more than enough material without being excessive. Robert made up the custom repair kit for a total cost, including shipping, of $35. What a relief. For G109B owners, add another $15, and Robert will also send the rivet and “O†ring required to reassemble the Elevator Push/Pull tube. Removing the Push/Pull tube is easily accomplished. If you prefer, you can ship the removed rod to Robert and he will perform the inspection and, if indicated, repair/replace the push/pull tube. If you send him your unit, Robert will perform the required inspection and return a serviceable assembly to you. Robert will also provide the appropriate documentation with the returned unit. The FAA used Grob factory prices in their estimated costs: · $78 for the rivet, “O†ring, and LPS-3 (vs $15 rivet and “O†ring from Robert) or · $680 for a new, or rebuilt, assembly if there is corrosion present on the thin wall tube. (Robert does not know his replacement cost yet, if the tube is unserviceable, but is confident it will be better than Grob’s.) I want to publicly thank Robert for eliminating the major headaches we confronted on these two AD’s. Robert Mudd Composite Aircraft Repair P.O. Box 2010 Moriarty, NM 87035 robertmudd1u@aol.com 505-269-8234