# Airworthiness Directives; The Boeing Company Airplanes
> **Rule** · Final rule. · Published 2020-01-17 · Effective 2020-02-21 · 85 FR 2867
## Document
- **Document number:** 2020-00700
- **Category:** airworthiness
- **Manufacturer:** The Boeing Company
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 85 FR 2867
- **Publication date:** 2020-01-17
- **Effective date:** 2020-02-21
- **FAA docket:** Docket No. FAA-2019-0478
## Abstract

The FAA is superseding Airworthiness Directive (AD) 2017-12- 07, which applied to certain The Boeing Company Model 737-800, -900, and -900ER series airplanes. AD 2017-12-07 required replacing the affected left temperature control valve and control cabin trim air modulating valve. This AD retains the requirements of AD 2017-12-07, expands the applicability to include additional airplanes, and adds a new requirement for certain airplanes to identify and replace the affected parts. This AD was prompted by reports of in-flight failure of the left temperature control valve and control cabin trim air modulating valve. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2020/01/17/2020-00700/airworthiness-directives-the-boeing-company-airplanes)
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