# Proposed AD FAA-2006-25174: Learjet Model 45 Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2008-01-03
- Products: Learjet
- Product type: Aircraft
- Action: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.
- Published: June 18, 2007, 72 FR 33415
- Comments due: July 13, 2007
- Became: [AD 2008-01-03](https://openairdocs.org/ad/2008-01-03)
- Docket: FAA-2006-25174 (https://www.regulations.gov/docket/FAA-2006-25174, where comments are filed)
- Project: 2005-NM-007-AD
- FR document: E7-11682
- Official PDF: https://openairdocs.org/files/sha256/c7/81/c7812165b31f69821a183613e73919b19bc27517a7bd25fc44e7dd7ab3080ad8 (from https://www.govinfo.gov/content/pkg/FR-2007-06-18/pdf/E7-11682.pdf)
- Federal Register: https://www.federalregister.gov/documents/2007/06/18/E7-11682/airworthiness-directives-learjet-model-45-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B35DFCFB0FBF876A862572FE00597FAE.0001
- Page: https://openairdocs.org/proposed/FAA-2006-25174

## Summary

The FAA is revising an earlier proposed airworthiness directive (AD) for certain Learjet Model 45 airplanes. The original NPRM would have required revising the Airworthiness Limitations section of the airplane maintenance manual to incorporate certain inspections and compliance times to detect fatigue cracking of certain principal structural elements (PSEs). The original NPRM resulted from new and more restrictive life limits and inspection intervals for certain PSEs. This action revises the original NPRM by changing the applicability to add certain airplanes. We are proposing this supplemental NPRM to ensure that fatigue cracking of various PSEs is detected and corrected; such fatigue cracking could adversely affect the structural integrity of these airplanes.

## Notices in this docket

- Jun 26, 2006: Notice of proposed rulemaking (NPRM). (first notice), FR document E6-10004, comments due Aug 10, 2006 (https://www.federalregister.gov/documents/2006/06/26/E6-10004/airworthiness-directives-learjet-model-45-airplanes)
- Jun 18, 2007: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period., FR document E7-11682, comments due Jul 13, 2007 (https://www.federalregister.gov/documents/2007/06/18/E7-11682/airworthiness-directives-learjet-model-45-airplanes)

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