AD Amdt-39-11418
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Various | Transport Category | Airworthiness Directives; Various Transport Category Airplanes Equipped With Mode ``C'' Transponder(s) With Single Gillham Code Altitude Input |
Unsafe Condition
False TCAS II advisories during level flight due to inaccurate airplane altitude reporting from Mode 'C' transponders with single Gillham code altitude input.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Conduct repetitive tests on Mode 'C' transponders, air data computers, and certain wiring connections to detect discrepancies. Perform corrective actions if discrepancies are found.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Before further flight
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Various transport category airplanes equipped with certain Mode 'C' transponders with single Gillham code altitude input.
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
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