# Proposed AD FAA-2011-0260: Bombardier, Inc. Model DHC-8-400 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2011-13-08
- Products: Bombardier
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: March 29, 2011, 76 FR 17362
- Comments due: May 13, 2011
- Became: [AD 2011-13-08](https://openairdocs.org/ad/2011-13-08)
- Docket: FAA-2011-0260 (https://www.regulations.gov/docket/FAA-2011-0260, where comments are filed)
- Project: 2010-NM-242-AD
- FR document: 2011-7289
- Official PDF: https://openairdocs.org/files/sha256/a0/d1/a0d1f21376d3c9e7d5217a25a39cc18779686c55575b3a5d04b62aa8c8f6dd96 (from https://www.govinfo.gov/content/pkg/FR-2011-03-29/pdf/2011-7289.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/03/29/2011-7289/airworthiness-directives-bombardier-inc-model-dhc-8-400-series-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/708CDC84FF0C071F86257862004CBFE2.0001
- Page: https://openairdocs.org/proposed/FAA-2011-0260

## 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:

Several reports have been received on the elevator power control units (PCUs) where the shaft (tailstock) swaged bearing liners had shown a higher than normal rate of wear. Investigation revealed that the excessive wear was due to the paint contamination between the bearing roller and bearing liner. The bearing paint contamination is known to be abrasive and could seize the bearing.

This condition, if not corrected, could lead to excessive airframe vibrations and difficulties in aircraft pitch control. * * * * *

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

## Notices in this docket

- Mar 29, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-7289, comments due May 13, 2011 (https://www.federalregister.gov/documents/2011/03/29/2011-7289/airworthiness-directives-bombardier-inc-model-dhc-8-400-series-airplanes)

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