Airworthiness Directives; Airbus Airplanes

We are superseding an existing airworthiness directive (AD) for all Airbus Model A300 B4-600, B4-600R and A300 F4-600R series airplanes, Model A300 C4-605R Variant F airplanes, and Model A310 series airplanes. That AD currently requires modifying the wiring in the right-hand electronics rack. This new AD requires replacing the cockpit multi-tank indicators (MTI), and for certain airplanes, replacing high-level, low-level, and overflow sensors and their harness connectors, and re-instating the low-level warning indication to the cockpit MTI. This AD was prompted by reports of failures of four fuel level sensor-amplifier and MTI units. This AD also adds Model A310 series airplanes to the applicability. We are issuing this AD to prevent degradation of the electrical insulation sleeves of the low- level indication lamps on the MTI, which could cause a short circuit that might result in high voltage being conveyed to the high- and low- level sensors in the wing tanks. This condition could cause the level sensor to heat above acceptable limits, possibly resulting in a fuel tank explosion, and consequent loss of the airplane.