Airworthiness Directive · Amendment 39-15258 · Boeing Model 707 Airplanes and Model 720 and 720B Series Airplanes
Boeing Model 707 Airplanes and Model 720 and 720B Series Airplanes
This AD applies to all Boeing Model 707-100 long body, -200, -100B long body, and -100B short body series airplanes; and Model 707-300, -300B, -300C, and -400 series airplanes; and Model 720 and 720B series airplanes; certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all Boeing Model 707 airplanes and Model 720 and 720B series airplanes. This AD requires accomplishing an airplane survey to define the configuration of certain system installations, and repair of any discrepancy found. This AD also requires modifying the fuel system by installing lightning protection for the fuel quantity indication system (FQIS), ground fault relays for the fuel boost pumps, and additional power relays for the center tank fuel pumps and uncommanded on- indication lights at the flight engineer's panel. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent certain failures of the fuel pumps or FQIS, which could result in a potential ignition source inside the fuel tank, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Within 12 months after the effective date of this AD: Conduct an airplane survey that defines the configuration of system installations for the wing leading edges, wing-to-body area, electrical equipment bay, flight deck, and FQIS using a method approved in accordance with the procedures specified in paragraph (h)(1) of this AD. If any discrepancy is detected, repair before further flight using a method approved in accordance with the procedures specified in paragraph (h)(1) of this AD. Submit the survey results to the Manager, Seattle Aircraft Certification Office (ACO), FAA, 1601 Lind Avenue SW., Renton, Washington 98057-3356, at the applicable time specified in paragraph (f)(1) or (f)(2) of this AD. The report must include the survey results (e.g., photographs and sketches, part numbers of FQIS components and fuel pumps, and the actual configuration of FQIS and the fuel pump control systems), a description of any discrepancy found, the airplane serial number, and the number of landings and flight hours on the airplane. Under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120-0056.
(1) If the survey was done after the effective date of this AD: Submit the report within 30 days after the survey.
(2) If the survey was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.
Note 1: For the purposes of this AD, “discrepancy” is defined as any wear or deterioration (e.g., damage, fluid leaks, corrosion, cracking, or system failures) that might prevent the airplane from being in an airworthy condition.
Within 72 months after the effective date of this AD: Modify the fuel system as specified in paragraphs (g)(1), (g)(2), and (g)(3) of this AD, using a method approved in accordance with the procedures specified in paragraph (h)(1) of this AD.
(1) Replace the FQIS wire bundle along the leading edge of the left and right wings with a new wire bundle that has a lightning shield that is separated from other wiring.
(2) Replace each fuel pump relay with a ground fault interrupter relay.
(3) Install redundant power relays for the center tank fuel pumps and uncommanded on-indication lights at the flight engineer's panel.
