# Proposed AD FAA-2016-6426: The Boeing Company Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2017-02-12
- Products: Boeing
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: May 10, 2016, 81 FR 28774
- Comments due: June 24, 2016
- Became: [AD 2017-02-12](https://openairdocs.org/ad/2017-02-12)
- Docket: FAA-2016-6426 (https://www.regulations.gov/docket/FAA-2016-6426, where comments are filed)
- Project: 2016-NM-023-AD
- FR document: 2016-10634
- Official PDF: https://openairdocs.org/files/sha256/23/bb/23bb878509e5f7c4e39465ae9fed97bd115ab06974fd5d738cd57e2459c5aba0 (from https://www.govinfo.gov/content/pkg/FR-2016-05-10/pdf/2016-10634.pdf)
- Federal Register: https://www.federalregister.gov/documents/2016/05/10/2016-10634/airworthiness-directives-the-boeing-company-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D294191F9C088F8386257FAF004AF063.0001
- Page: https://openairdocs.org/proposed/FAA-2016-6426

## Summary

We propose to adopt a new airworthiness directive (AD) for all The Boeing Company Model 737-300, -400, and -500 series airplanes. This proposed AD was prompted by reports of intergranular cracks on the front spar chord lugs of the outboard horizontal stabilizer. This proposed AD would require repetitive inspections of the front spar chord lugs and lug bores of the horizontal stabilizer, and repair if necessary. We are proposing this AD to detect and correct cracking of the front spar chord lugs of the horizontal stabilizer. Such cracking could cause stabilizer instability, adversely affect controllability of the airplane, and adversely affect the structural integrity of the airplane.

## Notices in this docket

- May 10, 2016: Notice of proposed rulemaking (NPRM). (first notice), FR document 2016-10634, comments due Jun 24, 2016 (https://www.federalregister.gov/documents/2016/05/10/2016-10634/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.