A new airworthiness directive effective January 4, 2010 is being adopted regarding certain Boeing Model 777-200, -200LR, -300, and -300ER series airplanes. This AD requires inspections for scribe lines in the skin along lap joints, butt joints, certain external doublers, and the large cargo door hinges; and related investigative and corrective actions if necessary. The AD results from reports of scribe lines found at lap joints and butt joints, around external doublers, and at locations where external decals had been removed. We are issuing this AD to detect and correct scribe lines, which can develop into fatigue cracks in the skin. Undetected fatigue cracks can grow and cause sudden decompression of the airplane.
Also effective January 4 is another new directive regarding the landing gear of 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. This AD is intented to prevent stress corrosion cracking of the forward trunnion pins, which could result in fracture of the pins and consequent collapse of the MLG.