AD 91-23-09
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 747-400 Series | Airworthiness Directives; BOEING Model 747-400 Series Airplanes |
| aircraft | The Boeing Company | 747-400D Series | Airworthiness Directives; BOEING Model 747-400 Series Airplanes |
Unsafe Condition
Fire due to overheated terminals and/or loss of power to the standby electrical power system.
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Required Actions
Inspect nuts on terminal strips TD469 and TD470 for proper torque of 65 to 75 inch-pounds. Re-torque any improperly torqued nut prior to further flight. Compliance must follow Boeing Process Specification BAC 5159, Revision F, dated March 1, 1991.
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Compliance Time
Within 20 days after the effective date of this AD, unless previously accomplished.
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Affected Aircraft
Boeing Model 747-400 series airplanes; line numbers 813 through 845, inclusive; certificated in any category.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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