AD 2021-18-17
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Boeing | Company | Airworthiness Directives; The Boeing Company Airplanes |
Unsafe Condition
The airplane may not capture or track the glideslope correctly during autopilot coupled instrument landing system (ILS) approaches, which could allow the airplane to descend below the glideslope beam and result in controlled flight into terrain on airplanes that do not have the upgraded flight control computer (FCC) operational program software (OPS) installed.
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Required Actions
Inspect for part numbers of the operational program software (OPS) of the flight control computers (FCCs), and update the version of the FCC OPS if necessary. Install and test an updated version of the FCC OPS. Prohibit installing Rockwell Collins FCC OPS software versions P1.1, P2.0, P3.0, P8.0, and P9.0.
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Compliance Time
Before further flight
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Affected Aircraft
The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes.
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Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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