Summary
We propose to supersede airworthiness directive (AD) 2009-24- 07, which applies to certain The Boeing Company Model 737-600, -700, - 700C, and -800 series airplanes. AD 2009-24-07 currently requires repetitive lubrications of the right and left main landing gear (MLG) forward trunnion pins. AD 2009-24-07 also requires an inspection for discrepancies of the transition radius of the MLG forward trunnion pins, and corrective actions if necessary. For certain airplanes, AD 2009-24-07 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 would terminate the actions required by AD 2009-24-07. This proposed AD would add airplanes to the applicability of AD 2009-24-07. We are proposing 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.