Action
Final rule.
Summary
We are superseding an existing airworthiness directive (AD) for certain The Boeing Company Model 707 airplanes, and Model 720 and 720B series airplanes. That AD currently requires replacing wiring for the fuel boost pumps and override pumps with new wiring, installing Teflon sleeving on the wiring, and doing associated actions; and doing repetitive inspections to detect damage of the wiring or evidence of a fuel leak. This new AD reduces the repetitive inspection interval. This AD was prompted by a determination that an inspection interval must be reduced. We are issuing this AD to detect and correct damaged wiring for the fuel boost pumps and override pumps, which could cause electrical arcing that could puncture the conduit containing the wire, and result in a fuel tank explosion or a fire adjacent to the fuel tank.