AD 97-20-01 R1
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 in the lower spar fitting lug or the lower spar fitting body could result in failure of the strut and separation of the engine from the airplane.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Perform a detailed visual inspection and an ultrasonic inspection to detect cracks, corrosion, or damage of the lower spar fitting body and lug. If no issues are found, repeat inspections at intervals not exceeding 400 landings. If cracks, corrosion, or damage are detected, replace the lower spar fitting with a new steel fitting or modify the nacelle strut and wing structure as per specified ADs before further flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 90 days after October 7, 1997 (the effective date of AD 97-20-01, amendment 39-10139)
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Boeing Model 747 series airplanes with line numbers 1 through 500 inclusive equipped with Pratt & Whitney Model JT9D-3, -7, or -7Q engines, or line numbers 202, 204, 232, or 257 equipped with General Electric Model CF6 series engines; certificated in any category; and on which the strut/wing modification has not been accomplished per AD 95-10-16 or 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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