Summary
The FAA proposes to adopt a new airworthiness directive (AD) for certain Boeing Model 747-100 and -200B series airplanes. This proposed AD would require installing bonding clips and bonding jumpers from the housing of each fuel pump to airplane structure outside the fuel tanks. This proposed AD is prompted by the results of fuel system reviews conducted by the manufacturer. We are proposing this AD to ensure adequate electrical bonding between the housing of each fuel pump and airplane structure outside the fuel tanks. Inadequate electrical bonding, in the event of a lightning strike or pump electrical fault, could cause electrical arcing and ignition of fuel vapor in the wing fuel tank, which could result in a fuel tank explosion.