AD FAA-2012-0265

We are superseding an existing airworthiness directive (AD) for certain Dassault Aviation Model FALCON 7X airplanes. That AD currently requires revising the Abnormal Procedures and Limitations sections of the Dassault F7X Airplane Flight Manual. This new AD requires a test of the power distribution control units (PDCU) cards and generator control units (GCU) cards to detect faulty components, and if any faulty components are found, replacing any affected PDCU or GCU card. This AD was prompted by a determination that additional actions are necessary to address the identified unsafe condition. We are issuing this AD to detect and correct a leakage failure mode of transient voltage suppression (TVS) diodes used on PDCU cards or GCU cards in the primary power distribution boxes (PPDB), which, in combination with other system failures, could lead to loss of controllability of the airplane.