AD 2007-23-12

final rule
Data completeness: 80%

Airworthiness Directives; Boeing Model 707 Airplanes and Model 720 and 720B Series Airplanes

AD Number
2007-23-12
Status
final_rule
Effective Date
Product Category
aircraft
Docket
Docket No. FAA-2007-28828
FR Citation
72 FR 63800

Applicability

TypeManufacturerModelDetails
aircraft Boeing 707 Airworthiness Directives; Boeing Model 707 Airplanes and Model 720 and 720B Series Airplanes

Unsafe Condition

Failures of the fuel pumps or fuel quantity indication system (FQIS) could result in a potential ignition source inside the fuel tank, which, in combination with flammable fuel vapors, could lead to a fuel tank explosion and consequent loss of the airplane.

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Required Actions

Conduct an airplane survey within 12 months to define system configurations and repair any discrepancies before further flight. Modify the fuel system within 72 months by installing lightning protection for the FQIS, ground fault relays for fuel boost pumps, and redundant power relays for center tank fuel pumps and uncommanded on-indication lights.

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Compliance Time

Within 12 months for the survey and within 72 months for the fuel system modifications.

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Affected Aircraft

All Boeing Model 707-100 long body, -200, -100B long body, -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.

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Source: Official FAA Source ↗

Retrieved: Apr 4, 2026

Rights: U.S. Government Public Domain

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