Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800 and -900 series airplanes. This proposed AD would require an inspection of the fillet sealant at the inboard and outboard sides of the receptacles in the wheel wells of the main landing gear, and related investigative/ corrective actions if necessary. This proposed AD results from reports of in-production airplanes with missing or insufficient fillet sealant around the receptacles at the disconnect bracket. We are proposing this AD to prevent corrosion damage due to missing or insufficient fillet sealant. Such corrosion could result in insufficient electrical bonding between the connectors and the disconnect bracket, and consequent loss of the shielding that protects the wire bundles from lightning, electromagnetic interference (EMI), and high intensity radiated field (HIRF). Loss of lightning, EMI, and HIRF protection at those receptacles could cause failure of multiple electrical systems and subsequent loss of several critical control systems that are necessary for safe flight. In addition, a lightning strike could cause arcing in the fuel tank; this potential ignition source, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.