AD 2006-21-05
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Boeing | 747-400 | Airworthiness Directives; Boeing Model 747-400, 777-200, and 777-300 Series Airplanes |
Unsafe Condition
Increased pressure drop across the flight deck humidifier, leading to reduced airflow and potential inability to clear smoke in the flight deck.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Replace the cell stack of the flight deck humidifier with a supplier-tested cell stack or replace the cell stack with a blanking plate and deactivate the humidifier. Inspect the flight deck humidifier to determine part numbers and replace the cell stack if necessary. Allow blanking plates to be replaced with cell stacks.
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
Boeing Model 747-400, 777-200, and 777-300 series airplanes with specific humidifier configurations as outlined in the AD.
AI-generated summary from the source AD text. Verify against the official source before acting.
Source: Official FAA Source ↗
Retrieved: Apr 4, 2026
Rights: U.S. Government Public Domain
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