# Proposed AD FAA-2005-21779: McDonnell Douglas Model DC-9-10 Series Airplanes; DC-9-20 Series Airplanes; DC-9-30 Series Airplanes; DC-9-40 Series Airplanes; and DC-9-50 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2006-21-06
- Products: McDonnell Douglas
- Product type: Aircraft
- Action: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.
- Published: March 7, 2006, 71 FR 11328
- Comments due: April 3, 2006
- Became: [AD 2006-21-06](https://openairdocs.org/ad/2006-21-06)
- Docket: FAA-2005-21779 (https://www.regulations.gov/docket/FAA-2005-21779, where comments are filed)
- Project: 2002-NM-349-AD
- FR document: 06-2157
- Official PDF: https://openairdocs.org/files/sha256/c6/f9/c6f9776b8809ceb494c9f454621f77298be7393e7f90887cbf5b9bdc3d61298e (from https://www.govinfo.gov/content/pkg/FR-2006-03-07/pdf/06-2157.pdf)
- Federal Register: https://www.federalregister.gov/documents/2006/03/07/06-2157/airworthiness-directives-mcdonnell-douglas-model-dc-9-10-series-airplanes-dc-9-20-series-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/38DE68962F4D10288625712A005E4CA9.0001
- Page: https://openairdocs.org/proposed/FAA-2005-21779

## Summary

The FAA is revising an earlier NPRM for an airworthiness directive (AD) that applies to certain McDonnell Douglas transport category airplanes. The original NPRM would have superseded an existing AD that currently requires, among other things, revision of an existing program of structural inspections. The original NPRM proposed to require implementation of a program of structural inspections of baseline structure to detect and correct fatigue cracking in order to ensure the continued airworthiness of these airplanes as they approach the manufacturer's original fatigue design life goal. The original NPRM resulted from a significant number of these airplanes approaching or exceeding the design service goal on which the initial type certification approval was predicated. This new action revises the original NPRM by removing certain service information as acceptable methods of compliance. We are proposing this supplemental NPRM to detect and correct fatigue cracking that could compromise the structural integrity of these airplanes.

## Notices in this docket

- Jul 8, 2005: Notice of proposed rulemaking (NPRM). (first notice), FR document 05-13436, comments due Aug 22, 2005 (https://www.federalregister.gov/documents/2005/07/08/05-13436/airworthiness-directives-mcdonnell-douglas-model-dc-9-10-series-airplanes-dc-9-20-series-airplanes)
- Mar 7, 2006: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period., FR document 06-2157, comments due Apr 3, 2006 (https://www.federalregister.gov/documents/2006/03/07/06-2157/airworthiness-directives-mcdonnell-douglas-model-dc-9-10-series-airplanes-dc-9-20-series-airplanes)

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