Airworthiness Directive · Amendment 39-17353 · Electrical power
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 707-100 long body, -200, -100B long body, and -100B short body series airplanes; Model 707-300, -300B, -300C, and -400 series airplanes; and Model 720 and 720B series airplanes; certificated in any category; line numbers 1 through 941 inclusive.
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.
This paragraph restates the requirements of paragraph (a) of AD 2001-17-20, Amendment 39-12411 (66 FR 44954, August 27, 2001). Within 1 year or 4,000 flight hours after October 1, 2001 (the effective date of AD 2001-17-20), whichever occurs first: Replace the wiring for the fuel boost pumps and override pumps, install Teflon sleeving over the wiring, and do all associated actions, per the Accomplishment Instructions of Boeing Service Bulletin A3500, Revision 1, dated April 26, 2001. The associated actions include performing a general visual inspection of the area around each fuel boost pump and override pump for evidence of a fuel leak; finding the source of any fuel leak and repairing the affected area; replacing the conduit, if required; and performing a detailed visual inspection of the wiring installed in the conduit for evidence of electrical arcing or a fuel leak, or exposed copper wire. If replacement of the conduit is deferred per the Accomplishment Instructions of Boeing Service Bulletin A3500, Revision 1, dated April 26, 2001, repeat the inspection for fuel leaks every 500 flight hours until the conduit is replaced, and replace the conduit within 6,000 flight hours or 18 months, whichever occurs first.
(1) For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
(2) For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
This paragraph restates the requirements of paragraph (b) of AD 2001-17-20, Amendment 39-12411 (66 FR 44954, August 27, 2001), with a new compliance time. After replacement of the wiring per paragraph (g) of this AD, repeat the detailed visual inspection of the wiring for the fuel boost pumps and override pumps for damage, such as evidence of electrical arcing or exposed copper wire, or evidence of a fuel leak. After the effective date of this AD, repeat the inspection one time at the earlier of the times specified in paragraphs (h)(1) and (h)(2) of this AD, per the Accomplishment Instructions of Boeing Service Bulletin A3500, Revision 1, dated April 26, 2001. If any electrical arcing or exposed copper wire or evidence of a fuel leak is detected during any inspection per this paragraph, before further flight, do the applicable corrective actions (including finding the source of any fuel leak and repairing the affected area, replacing the wiring, replacing the conduit, or installing new Teflon sleeving; as applicable) according to the Accomplishment Instructions of Boeing Service Bulletin A3500, Revision 1, dated April 26, 2001. Repeat the inspection thereafter at intervals not to exceed 15,000 flight hours.
(1) Within 30,000 flight hours after the most recent inspection.
(2) At the later of the compliance times specified in paragraphs (h)(2)(i) and (h)(2)(ii) of this AD.
(i) Within 15,000 flight hours after the most recent inspection.
(ii) Within 3 years after the effective date of this AD.
