A fuel control system for an aircraft gas turbine engine that includes a thrust augmentation system. Another method for manufacturing a foam product comprises sealing a tube of material in a cavity of a mold, blowing air into the tube of material to form a skin comprising an interior surrounded by a wall, cutting an incision in the skin wall, inserting a bracket through the incision and into the skin interior, filling the skin interior with foam, and curing the foam. A method facilities communicating a message to one or more of the interconnected agents. A retaining ring is bridgingly interposed between the outer peripheral surface of the outer end portion of the spline shaft and the inner peripheral surface of the near-to-outer-end portion of the spline hole to thereby prevent the spline shaft from slipping out of the spline hole.