AD FAA-2006-26707

The FAA is adopting a new airworthiness directive (AD) for certain Airbus Model A330 airplanes and Model A340-200 and -300 series airplanes. This AD requires inspecting to determine the part number of certain S4- and MZ-type spoiler servo controls (SSCs). For certain other airplanes, this AD requires inspecting to determine the part number of all SSCs. This AD also requires replacing any affected SSC with a new SSC. This AD results from a new load duty cycle defined by the manufacturer. Additional fatigue tests and calculations done on this basis indicated that the spoiler valve manifold of the S4-type SSCs, and, on certain airplanes, the maintenance cover of the MZ-type SSCs, may crack during its service life due to pressure impulse fatigue. We are issuing this AD to prevent fatigue cracking of certain SSCs, which could result in hydraulic leakage and consequent loss of SSC function and loss of the associated hydraulic system. These conditions could affect all three hydraulic systems, which could result in reduced controllability of the airplane.