# Airplanes
> **Rule** · Final rule; request for comments. · Published 1999-09-01 · Effective 1999-09-16 · 64 FR 47656
## Document
- **Document number:** 99-22531
- **Category:** other
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 64 FR 47656
- **Publication date:** 1999-09-01
- **Effective date:** 1999-09-16
- **FAA docket:** Docket No. 99-NM-187-AD
## Abstract

This amendment adopts a new airworthiness directive (AD) that is applicable to all Boeing Model 737-100, -200, -300, -400, and -500 series airplanes. This action requires repetitive replacements of the airplane battery with a new or reconditioned battery, and for certain airplanes, replacement of the battery charger with a new or serviceable battery charger. This action also requires performing repetitive tests to determine the condition of a certain diode of the Generator Control Units (GCU); and corrective actions, if necessary. This amendment is prompted by an incident during which all electrical power was lost due to a combination of a weak or depleted battery and the failure of a certain diode of the GCU. The actions specified in this AD are intended to prevent failure of all electrically powered airplane systems, which could result in the inability to continue safe flight and landing.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/09/01/99-22531/airplanes)
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