AD FAA-2018-0409

We are superseding Airworthiness Directive (AD) 2017-16-05, which applied to certain The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. AD 2017-16-05 required a one- time detailed visual inspection for discrepancies in the Krueger flap bullnose attachment hardware, and related investigative and corrective actions if necessary. This AD adds airplanes and an additional inspection to determine if any Krueger flap no. 1, 2, 3, or 4 has been replaced, and related investigative and corrective actions. Since this is a rotable parts issue, the applicability of this AD has been expanded beyond the airplanes listed in the related service bulletin to include all airplanes on which a Krueger flap bullnose may be installed. This AD was prompted by a report of a Krueger flap bullnose departing an airplane during taxi, which caused damage to the wing structure and thrust reverser, and a report of a missing no. 2 Krueger flap bullnose hinge bolt from an airplane that was not included in the effectivity of AD 2017-16-05. We are issuing this AD to address the unsafe condition on these products.