# Airworthiness Directives; The Boeing Company Airplanes
> **Rule** · Final rule. · Published 2021-04-21 · Effective 2021-05-26 · 86 FR 20621
## Document
- **Document number:** 2021-08213
- **Category:** airworthiness
- **Manufacturer:** The Boeing Company
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 86 FR 20621
- **Publication date:** 2021-04-21
- **Effective date:** 2021-05-26
- **FAA docket:** Docket No. FAA-2019-0480
## Abstract

The FAA is superseding Airworthiness Directive (AD) 2013-07- 09, which applied to certain The Boeing Company Model 737-700, -700C, - 800, and -900ER series airplanes, Model 747-400F series airplanes, and Model 767-200 and -300 series airplanes. AD 2013-07-09 required a general visual inspection for affected serial numbers of the crew oxygen mask stowage box units, and replacement or re-identification as necessary. This AD retains the requirements of AD 2013-07-09 and expands the applicability. This AD was prompted by a determination that the affected parts may be installed on airplanes outside the original applicability of AD 2013-07-09. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2021/04/21/2021-08213/airworthiness-directives-the-boeing-company-airplanes)
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