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

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 737-600, -700, and -800 series airplanes, that currently requires repetitive inspections to detect discrepancies of the quick-disconnect coupling on the fuel hose located at the fan case firewall; corrective action, if necessary; and installation of a clamp shell on the coupling to prevent separation of the coupling halves. This amendment limits the applicability of the existing requirements, clarifies certain existing requirements, and requires removal of the clamp shell installed previously and replacement of the existing quick-disconnect fuel supply hose, coupling, and strut fitting with new, fixed-B-nut-type parts. Such replacement ends the requirement for repetitive inspections. The actions specified by this AD are intended to prevent major fuel leakage due to excessive wear of the quick-disconnect coupling on the fuel hose, fire in the engine nacelle, and consequent loss of thrust from the affected engine, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.