AD 2001-23-13
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Boeing | 747 | Airworthiness Directives; Boeing Model 747 Series Airplanes |
Unsafe Condition
Installation of a discrepant (``Belleville'' spring design) torque brake in the flap drive transmission of the trailing edge flaps at positions 2 and 7, which could result in damage to the flap system, adjacent systems, or structural components; or excessive skew of the trailing edge flap, leading to flap asymmetry and reduced controllability of the airplane.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect the flap drive transmission at positions 2 and 7 to determine if a discrepant torque brake is installed. If a discrepant torque brake is found, replace the transmission with a new, improved one or rework the existing transmission by replacing the torque brake with a new or reworked torque brake having the specified part number. Restrict installation of affected spare parts as of December 31, 2001.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 18 months or 7,500 flight hours after December 31, 2001, whichever occurs later.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Boeing Model 747 series airplanes, line numbers 0001 through 1207, excluding line number 1174 and Model 747SP series airplanes.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.