AD 99-08-01
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
Corrosion and cracks located at the four fasteners that attach to the aft end of the upper link assembly on the number 2 and number 3 engine struts could lead to failure of the upper link, subsequent damage to other strut support structure, and in-flight separation of an engine from the airplane.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Conduct repetitive detailed visual inspections for corrosion and repetitive high frequency eddy current (HFEC) inspections for cracks on the upper link assembly of the number 2 and 3 engine struts. Perform corrective actions if corrosion or cracks are found, including removal, installation, or replacement of the upper link in accordance with either the Boeing 747 Airplane Maintenance Manual or an operator's equivalent procedure.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the compliance time specified in the referenced service information, extended to coincide with the compliance time for all affected airplanes as revised in the final rule.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Boeing Model 747 series airplanes, line positions 1 through 886 inclusive; equipped with Pratt & Whitney JT9D-3 or -7, or General Electric CF6-45 or -50 engine struts.
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
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.