# Proposed AD FAA-2011-0720: Bombardier Inc. Model DHC-8-400 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2011-24-03
- Products: Bombardier
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: August 1, 2011, 76 FR 45713
- Comments due: September 15, 2011
- Became: [AD 2011-24-03](https://openairdocs.org/ad/2011-24-03)
- Docket: FAA-2011-0720 (https://www.regulations.gov/docket/FAA-2011-0720, where comments are filed)
- Project: 2010-NM-252-AD
- FR document: 2011-19330
- Official PDF: https://openairdocs.org/files/sha256/c4/17/c41759696c226a359d9cba9ac861519a05e81c8e015842ecb16a64cb156713c2 (from https://www.govinfo.gov/content/pkg/FR-2011-08-01/pdf/2011-19330.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/08/01/2011-19330/airworthiness-directives-bombardier-inc-model-dhc-8-400-series-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/14600654A2602225862578DF004B8C9D.0001
- Page: https://openairdocs.org/proposed/FAA-2011-0720

## 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:

There has been one reported incident where the main landing gear (MLG) failed to extend during testing of the MLG alternate release system. Investigation revealed that the door release lever bushing was worn, causing an increase in the lateral movement of the release cable system. An increase in free-play within the release cable system would cause additional wear to the door release lever bushing and may lead to the turnbuckle fouling against the nacelle frame. The bushing wear at the door release lever and turnbuckle fouling could cause a failure in the alternate release system, preventing the landing gear from extending in the case of a failure of the normal MLG extension/retraction system.

* * * * *

The unsafe condition is loss of control during landing. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

## Notices in this docket

- Aug 1, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-19330, comments due Sep 15, 2011 (https://www.federalregister.gov/documents/2011/08/01/2011-19330/airworthiness-directives-bombardier-inc-model-dhc-8-400-series-airplanes)

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