Airworthiness Directives; The Boeing Company Model 727, 727C, 727-100, 727-100C, 727-200, and 727-200F Series Airplanes
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires replacing the existing unshielded fuel quantity indication system (FQIS) wire bundles with double shielded FQIS wire bundles, installing a new wire feed-through fitting, and grounding the wire shields, as applicable; and doing repetitive low frequency eddy current (LFEC) inspections for cracking of the fuselage skin, and corrective actions if necessary. This AD also requires revising the maintenance program to incorporate certain airworthiness limitations. This AD was prompted by fuel system reviews conducted by the manufacturer. We are issuing this AD to increase the level of protection from lightning strikes and prevent the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.