AD 90-20-10
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
The unsafe condition could occur if the horizontal stabilizer trim actuator, position sensor, or control system components fail, leading to potential uncommanded movement of the horizontal stabilizer trim, which could result in reduced control effectiveness and subsequent loss of aircraft controllability.
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Required Actions
Conduct an inspection of the horizontal stabilizer trim actuator, position sensor, and control system components. Perform necessary repairs or replacements based on inspection findings. Implement a repetitive inspection program with specific intervals to ensure ongoing compliance.
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Compliance Time
Prior to the accumulation of 500 flight hours, or as soon as practicable thereafter, but in no case later than 180 days after the effective date of this AD.
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Affected Aircraft
Boeing Model 747 series airplanes, excluding specific models modified under STC SA####-##, as listed in the AD's applicability section.
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Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
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