AD 91-21-10
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | The Boeing Company | 767-200 Series | Airworthiness Directives; BOEING Model 767 Series Airplanes |
| aircraft | The Boeing Company | 767-300 Series | Airworthiness Directives; BOEING Model 767 Series Airplanes |
| aircraft | The Boeing Company | 767-300F Series | Airworthiness Directives; BOEING Model 767 Series Airplanes |
Unsafe Condition
Uncommanded asymmetric movement of the leading edge slats due to failure of the No-Back brake combined with disconnect of the torque tube.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Conduct torque tube and overtravel stop inspections within 2,000 flight hours after AD effective date and every 3,000 flight hours thereafter. Replace offset gearboxes within 18 months (Groups 1 and 2) or 24 months (Group 3) after AD effective date. Use Boeing Alert Service Bulletin 767-27A0095, Revision 3.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 2,000 flight hours after the effective date of this AD and thereafter at intervals not to exceed 3,000 flight hours
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Boeing Model 767 series airplanes, Groups 1, 2, and 3 as listed in Boeing Alert Service Bulletin 767-27A0095, Revision 3, dated May 23, 1991.
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.