AD FAA-2009-0411

We are adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, and -800 series airplanes. This AD requires repetitive lubrications of the right and left main landing gear (MLG) forward trunnion pins. This AD also requires an inspection for discrepancies of the transition radius of the MLG forward trunnion pins, and corrective actions if necessary. For certain airplanes, this AD also requires repetitive detailed inspections for discrepancies (including finish damage, corrosion, pitting, and base metal scratches) of the transition radius of the left and right MLG trunnion pins, and corrective action if necessary. Replacing or overhauling the trunnion pins terminates the actions required by this AD. This AD results from a report that the protective finishes on the forward trunnion pins for the left and right MLG might have been damaged during final assembly. We are issuing this AD to prevent stress corrosion cracking of the forward trunnion pins, which could result in fracture of the pins and consequent collapse of the MLG.