# Airworthiness Directives; Boeing Model 747 Airplanes
> **Rule** · Final rule. · Published 2008-09-12 · Effective 2008-10-17 · 73 FR 52911
## Document
- **Document number:** E8-20364
- **Category:** airworthiness
- **Manufacturer:** Boeing Model 747
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 73 FR 52911
- **Publication date:** 2008-09-12
- **Effective date:** 2008-10-17
- **FAA docket:** Docket No. FAA-2008-0091
## Abstract

We are adopting a new airworthiness directive (AD) for certain Boeing Model 747 airplanes. This AD requires modification of the refuel valve control unit for the reserve fuel tanks. This AD also requires a revision to the FAA-approved maintenance program to incorporate airworthiness limitation (AWL) No. 28-AWL-20 or AWL No. 28-AWL-25, as applicable. This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent lightning-induced electrical energy from entering a reserve fuel tank through the refuel valve, which could result in a fuel tank explosion and consequent loss of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2008/09/12/E8-20364/airworthiness-directives-boeing-model-747-airplanes)
---
*AI Analytics · CC0 1.0*