# Proposed AD FAA-2009-0526: Bombardier Model DHC-8-400 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2009-18-12
- Products: Bombardier
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: June 10, 2009, 74 FR 27476
- Comments due: July 10, 2009
- Became: [AD 2009-18-12](https://openairdocs.org/ad/2009-18-12)
- Docket: FAA-2009-0526 (https://www.regulations.gov/docket/FAA-2009-0526, where comments are filed)
- Project: 2009-NM-029-AD
- FR document: E9-13505
- Official PDF: https://openairdocs.org/files/sha256/db/f0/dbf09bdc08659b2ce71adda78ba30c830ce952785095df6f76efa1f6cd5b9ebf (from https://www.govinfo.gov/content/pkg/FR-2009-06-10/pdf/E9-13505.pdf)
- Federal Register: https://www.federalregister.gov/documents/2009/06/10/E9-13505/airworthiness-directives-bombardier-model-dhc-8-400-series-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1C8FBC92DBE3FD34862575D100462CF6.0001
- Page: https://openairdocs.org/proposed/FAA-2009-0526

## 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:

Four aircraft have experienced a dual AC generator shutdown, caused by a broken propeller de-ice bus bar which short-circuited with the backplate assembly. * * * A short circuit can cause a dual AC generator shutdown that, particularly in conjunction with an engine failure in icing conditions, could result in reduced controllability of the aircraft. * * * * * Reduced controllability of the airplane in certain operating conditions affects continued safe flight and landing. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

## Notices in this docket

- Jun 10, 2009: Notice of proposed rulemaking (NPRM). (first notice), FR document E9-13505, comments due Jul 10, 2009 (https://www.federalregister.gov/documents/2009/06/10/E9-13505/airworthiness-directives-bombardier-model-dhc-8-400-series-airplanes)

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