# Proposed AD FAA-2006-24270: Boeing Model 777 Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2007-17-12
- Products: Boeing
- Product type: Aircraft
- Action: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.
- Published: June 18, 2007, 72 FR 33411
- Comments due: July 13, 2007
- Became: [AD 2007-17-12](https://openairdocs.org/ad/2007-17-12)
- Docket: FAA-2006-24270 (https://www.regulations.gov/docket/FAA-2006-24270, where comments are filed)
- Project: 2005-NM-200-AD
- FR document: E7-11679
- Official PDF: https://openairdocs.org/files/sha256/b3/d4/b3d495caff695bc3ee5ce65d824e9b4488e4d2e066c690ca005c1e4b211e7eb3 (from https://www.govinfo.gov/content/pkg/FR-2007-06-18/pdf/E7-11679.pdf)
- Federal Register: https://www.federalregister.gov/documents/2007/06/18/E7-11679/airworthiness-directives-boeing-model-777-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/589DCEFA4D0F3FB4862572FE00597F84.0001
- Page: https://openairdocs.org/proposed/FAA-2006-24270

## Summary

The FAA is revising an earlier proposed airworthiness directive (AD) for all Boeing Model 777-200, -300, and -300ER series airplanes. The original NPRM would have required, for the drive mechanism of the horizontal stabilizer, repetitive detailed inspections for discrepancies; repetitive lubrication of the ballnut and ballscrew; repetitive measurements of the freeplay between the ballnut and the ballscrew; and corrective action if necessary. The original NPRM resulted from a report of extensive corrosion of a ballscrew in the drive mechanism of the horizontal stabilizer on a Boeing Model 757 airplane, which is similar in design to the ballscrew on Model 777 airplanes. This action revises the original NPRM by adding airplanes to the applicability. We are proposing this supplemental NPRM to prevent an undetected failure of the primary load path for the ballscrew in the horizontal stabilizer and subsequent wear and failure of the secondary load path, which could lead to loss of control of the horizontal stabilizer and consequent loss of control of the airplane.

## Notices in this docket

- Mar 30, 2006: Notice of proposed rulemaking (NPRM). (first notice), FR document E6-4619, comments due May 15, 2006 (https://www.federalregister.gov/documents/2006/03/30/E6-4619/airworthiness-directives-boeing-model-777-airplanes)
- Jun 18, 2007: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period., FR document E7-11679, comments due Jul 13, 2007 (https://www.federalregister.gov/documents/2007/06/18/E7-11679/airworthiness-directives-boeing-model-777-airplanes)

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