Airworthiness Directives; Boeing Model 737-600, -700, -700C, and -800 Series Airplanes

The FAA is revising an existing airworthiness directive (AD) that applies to certain Boeing Model 737-600, -700, -700C, and -800 series airplanes. That AD currently requires inspecting/measuring the length of the attachment fasteners between the nacelle support fittings and the lower wing skin panels, and related investigative/corrective actions if necessary. That AD resulted from a report from the manufacturer that in production, during the installation of certain attachment fasteners for the nacelle support fittings, only one washer was installed instead of two. This new AD corrects errors found in the existing AD. We are issuing this AD to prevent inadequate fastener clamp-up, which could result in cracking of the fastener holes, cracking along the lower wing skin panels, fuel leaking from the wing fuel tanks onto the engines, and possible fire.