# Proposed AD FAA-2009-0938: PILATUS Aircraft Ltd. Model PC-7 Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Comment period closed
- Products: Pilatus
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: October 9, 2009, 74 FR 52156
- Comments due: November 23, 2009
- Docket: FAA-2009-0938 (https://www.regulations.gov/docket/FAA-2009-0938, where comments are filed)
- Project: 2009-CE-052-AD
- FR document: E9-24450
- Official PDF: https://openairdocs.org/files/sha256/7d/af/7daf2b07b3795b61ee8cc2ef5e0afc7037762dff9ce7bb3aed474fd9228ed0c9 (from https://www.govinfo.gov/content/pkg/FR-2009-10-09/pdf/E9-24450.pdf)
- Federal Register: https://www.federalregister.gov/documents/2009/10/09/E9-24450/airworthiness-directives-pilatus-aircraft-ltd-model-pc-7-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/42A662C2011C35388625764A0051A36F.0001
- Page: https://openairdocs.org/proposed/FAA-2009-0938

## Summary

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

This Airworthiness Directive (AD) is prompted due to the discovery of cracks caused by stress corrosion in the main-gear support struts. All the main-gear support struts that had cracks were made from material AA2024-T351 which has a lower resistance to stress corrosion cracking. Such cracks, if undetected, could lead to the failure of the strut during landing which could then cause the Main Landing Gear (MLG) to collapse.

The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

## Notices in this docket

- Oct 9, 2009: Notice of proposed rulemaking (NPRM). (first notice), FR document E9-24450, comments due Nov 23, 2009 (https://www.federalregister.gov/documents/2009/10/09/E9-24450/airworthiness-directives-pilatus-aircraft-ltd-model-pc-7-airplanes)

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