Airworthiness Directive · Amendment 39-19836 · Fuel
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 707-100 long body, -200, -100B long body, -100B short body, -300, -300B, -300C, and -400 series airplanes; and Model 720 and 720B series airplanes; certificated in any category; excluding airplanes equipped with a flammability reduction means (FRM) approved by the FAA as compliant with the Fuel Tank Flammability Reduction (FTFR) requirements of 14 CFR 25.981(b) or 14 CFR 26.33(c)(1).
The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 707 airplanes and Model 720 and 720B series airplanes. This AD was prompted by the FAA's analysis of the Model 707 and 720 fuel system reviews conducted by the manufacturer. This AD requires modifying the fuel quantity indicating system (FQIS) to prevent development of an ignition source inside the center fuel tank due to electrical fault conditions. The FAA is issuing this AD to address the unsafe condition on these products.
Within 60 months after the effective date of this AD, modify the fuel quantity indicating system (FQIS) to prevent development of an ignition source inside the center fuel tank due to electrical fault conditions, using a method approved in accordance with the procedures specified in paragraph (h) of this AD.
