AD 99-04-01
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
Fatigue cracking of the strut skin and spring beam support fittings, and cracked or loose fasteners of the support fittings could result in failure of the outboard nacelle struts and consequent separation of the engine.
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Required Actions
Perform a detailed visual inspection of the outboard nacelle struts as specified in Boeing Service Bulletins 747-54A2172 or Revision 1. Inspect spring beam support fittings for cracks, fasteners for cracks or looseness, and strut skin for cracks. Replace cracked support fittings with new ones prior to further flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Prior to the accumulation of 13,000 total flight cycles, or within 6 months after the effective date of this AD, whichever occurs later.
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Affected Aircraft
Boeing Model 747 series airplanes, line numbers 202 through 886 inclusive, equipped with General Electric Model CF6-45/50 and Pratt & Whitney Model JT9D-70 series engines; on which the strut/wing modification has not been accomplished in accordance with AD 95-13-07.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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