# Proposed AD FAA-2019-0478: The Boeing Company Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2020-01-11
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: July 8, 2019, 84 FR 32341
- Comments due: August 22, 2019
- Became: [AD 2020-01-11](https://openairdocs.org/ad/2020-01-11)
- Docket: FAA-2019-0478 (https://www.regulations.gov/docket/FAA-2019-0478, where comments are filed)
- FR document: 2019-14284
- Official PDF: https://openairdocs.org/files/sha256/ce/83/ce8343c1b1bc785399d6df115ee05fe11b675a2fb9d5cdfd35b09265d8ca3537 (from https://www.govinfo.gov/content/pkg/FR-2019-07-08/pdf/2019-14284.pdf)
- Federal Register: https://www.federalregister.gov/documents/2019/07/08/2019-14284/airworthiness-directives-the-boeing-company-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0A38E6795F7EA9648625843100587FBD.0001
- Page: https://openairdocs.org/proposed/FAA-2019-0478

## Summary

The FAA proposes to supersede Airworthiness Directive (AD) 2017-12-07, which applies to certain The Boeing Company Model 737-800, -900, and -900ER series airplanes. AD 2017-12-07 requires replacing the affected left temperature control valve and control cabin trim air modulating valve. Since the FAA issued AD 2017-12-07, the agency determined that the affected parts may be installed on airplanes outside the original applicability of AD 2017-12-07. This proposed AD would retain the requirements of AD 2017-12-07, expand the applicability to include those other airplanes, and add a new requirement for certain airplanes to identify and replace the affected parts. The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Jul 8, 2019: Notice of proposed rulemaking (NPRM). (first notice), FR document 2019-14284, comments due Aug 22, 2019 (https://www.federalregister.gov/documents/2019/07/08/2019-14284/airworthiness-directives-the-boeing-company-airplanes)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.