Airworthiness Directives; Short Brothers Model SD3 Airplanes

The FAA is adopting a new airworthiness directive (AD) for all Short Brothers Model SD3 airplanes. This AD requires installing additional fuel tank bonding jumpers, performing an in-place resistance check of the float switches, inspecting certain internal components of the fuel tanks, and performing related corrective actions if necessary. This AD also requires revisions to the Airworthiness Limitations section of the Instructions for Continued Airworthiness, and to the airplane flight manual procedures for operation during icing conditions and fuel system failures. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent ignition sources inside the fuel tanks, which could lead to fire or explosion.