# Proposed AD FAA-2004-18557: Lockheed Model 1329 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2005-01-02
- Products: Lockheed
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: July 7, 2004, 69 FR 40821
- Comments due: August 23, 2004
- Became: [AD 2005-01-02](https://openairdocs.org/ad/2005-01-02)
- Docket: FAA-2004-18557 (https://www.regulations.gov/docket/FAA-2004-18557, where comments are filed)
- Project: 2003-NM-174-AD
- FR document: 04-15381
- Official PDF: https://openairdocs.org/files/sha256/ac/7f/ac7fd6557a7b3cab3f7dbdeac73ecee9877150557c05a1494b60e9b104ecd722 (from https://www.govinfo.gov/content/pkg/FR-2004-07-07/pdf/04-15381.pdf)
- Federal Register: https://www.federalregister.gov/documents/2004/07/07/04-15381/airworthiness-directives-lockheed-model-1329-series-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/0E0CEC5D6D53B80F86256ECA0051897A.0001
- Page: https://openairdocs.org/proposed/FAA-2004-18557

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for certain Lockheed Model 1329 series airplanes. This proposed AD would require repetitive inspections to detect crack damage in the front spar cap assembly of the lower vertical stabilizer; reworking the spar cap doublers if no crack damage is found during any inspection; and repairing if any crack damage is found during any inspection. This proposed AD is prompted by reports of cracks in the front spar cap assembly of the lower vertical stabilizer at box beam station 24 on the aft side of the 25% chord line. We are proposing this AD to find and fix cracks in the front spar cap assembly of the lower vertical stabilizer, which could result in rapid crack propagation and failure of the front spar cap. Failure of the front spar cap could lead to loss of rudder control and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

## Notices in this docket

- Jul 7, 2004: Notice of proposed rulemaking (NPRM). (first notice), FR document 04-15381, comments due Aug 23, 2004 (https://www.federalregister.gov/documents/2004/07/07/04-15381/airworthiness-directives-lockheed-model-1329-series-airplanes)

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