# Proposed AD FAA-2011-1090: Bombardier, Inc. Model DHC-8-400 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2012-06-05
- Products: Bombardier
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: October 19, 2011, 76 FR 64847
- Comments due: December 5, 2011
- Became: [AD 2012-06-05](https://openairdocs.org/ad/2012-06-05)
- Docket: FAA-2011-1090 (https://www.regulations.gov/docket/FAA-2011-1090, where comments are filed)
- Project: 2011-NM-138-AD
- FR document: 2011-27009
- Official PDF: https://openairdocs.org/files/sha256/7a/39/7a39305dbfc9a29cf7a95f797ae9738d7ce1ad49950cce841cb9d03aea358e58 (from https://www.govinfo.gov/content/pkg/FR-2011-10-19/pdf/2011-27009.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/10/19/2011-27009/airworthiness-directives-bombardier-inc-model-dhc-8-400-series-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/707E308F5F9C974F8625792E0059CA60.0001
- Page: https://openairdocs.org/proposed/FAA-2011-1090

## 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:

One case of the inability to open the airstair door while on ground was reported in service. The airstair door seal did not deflate, preventing the airstair door from opening. It was found that the existing airstair door pneumatic shut-off valve control logic prevents the airstair door seal from deflating due to a single Input/Output Module failure under certain conditions. The inability to open the airstair door could impede evacuation in the event of an emergency.

* * * * *

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

## Notices in this docket

- Oct 19, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-27009, comments due Dec 5, 2011 (https://www.federalregister.gov/documents/2011/10/19/2011-27009/airworthiness-directives-bombardier-inc-model-dhc-8-400-series-airplanes)

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