AD 91-18-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 747-400 Series | Airworthiness Directives; BOEING Model 747-400 Series Airplanes |
Unsafe Condition
Loss of essential airplane electrical busses due to inadequate separation between wiring associated with differential protection current transformers for AC channels 1, 2, and 3 in the P6 panel.
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Required Actions
Reroute and add protective sleeving to wiring associated with differential protection current transformers for AC channels 1, 2, and 3 in the P6 panel per Boeing Service Bulletin 747-24-2154. Alternative methods or compliance time adjustments require FAA approval. Special flight permits may be issued under FAR 21.197 and 21.199.
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Compliance Time
within 180 days after the effective date of this AD, unless previously accomplished
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Affected Aircraft
Boeing Model 747-400 series airplanes listed in Boeing Service Bulletin 747-24-2154 dated February 7, 1991, 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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