# Airworthiness Directives; Boeing Model 747 Airplanes
> **Rule** · Final rule. · Published 2007-03-28 · Effective 2007-05-02 · 72 FR 14395
## Document
- **Document number:** E7-5557
- **Category:** airworthiness
- **Manufacturer:** Boeing Model 747
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 72 FR 14395
- **Publication date:** 2007-03-28
- **Effective date:** 2007-05-02
- **FAA docket:** Docket No. FAA-2004-19755
## Abstract

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 747 airplanes. This AD requires repetitive tests to detect hot air leaking from the trim air diffuser ducts or sidewall riser duct assemblies (collectively referred to in this AD as "TADDs"), related investigative actions, and corrective actions if necessary. This AD also provides an optional terminating action for the repetitive tests. This AD results from reports of sealant deteriorating on the outside of the center wing fuel tank and analysis that sealant may deteriorate inside the tank due to excess heat from leaking TADDs. We are issuing this AD to prevent leakage of fuel or fuel vapors into areas where ignition sources may be present, which could result in a fire or explosion.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2007/03/28/E7-5557/airworthiness-directives-boeing-model-747-airplanes)
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