AD 91-12-08
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 747-400 Series | Airworthiness Directives; BOEING Model 747-400 Series Airplanes |
Unsafe Condition
Use of erroneous DME information, decreased enroute RNAV accuracy, decreased terminal area navigation capabilities, and increased missed approaches due to Collins DME part number 622-4540-120 installation.
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Required Actions
Inspect airplane or records to determine if Collins DME part number 622-4540-120 is installed. If installed, add specified statements to AFM Limitations Section prior to further flight. Alternative compliance may be approved by FAA Manager, Seattle ACO.
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Compliance Time
within 10 days after the effective date of this AD, unless previously accomplished
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Affected Aircraft
All Model 747-400 series airplanes, 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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