AD 99-20-09
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 747-100 Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
| aircraft | The Boeing Company | 747-100B Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
| aircraft | The Boeing Company | 747-100B SUD Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
| aircraft | The Boeing Company | 747-200B Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
| aircraft | The Boeing Company | 747-200C Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
| aircraft | The Boeing Company | 747-200F Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
| aircraft | The Boeing Company | 747-300 Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
| aircraft | The Boeing Company | 747-400 Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
| aircraft | The Boeing Company | 747-400D Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
| aircraft | The Boeing Company | 747-400F Series | Airworthiness Directives; BOEING Model 747 Series Airplanes |
Unsafe Condition
Separation of the engine from the airplane due to migration of the tangential link upper bolt.
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Required Actions
Inspect the tangential link upper bolt nut orientation and torque value per Boeing Service Bulletin. Correct improper orientation or torque by removing and reinstalling parts or replacing with serviceable parts. Repeat inspections every 18 months. Replace bolt, nut, or safety links if missing or damaged as per the bulletin.
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Compliance Time
Within 90 days after February 16, 1996, or prior to further flight if discrepancies are found.
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Affected Aircraft
Boeing Model 747 series airplanes listed in Boeing Alert Service Bulletin 747-71A2277 or Service Bulletin 747-71A2277 Revisions 1 or 2.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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