# Proposed AD FAA-2011-0159: Bombardier, Inc. Model CL-600-2C10 (Regional Jet Series 700, 701, & 702), Model CL-600-2D15 (Regional Jet Series 705), and Model CL-600-2D24 (Regional Jet Series 900) Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2011-12-06
- Products: Bombardier
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: March 14, 2011, 76 FR 13536
- Comments due: April 28, 2011
- Became: [AD 2011-12-06](https://openairdocs.org/ad/2011-12-06)
- Docket: FAA-2011-0159 (https://www.regulations.gov/docket/FAA-2011-0159, where comments are filed)
- Project: 2010-NM-246-AD
- FR document: 2011-5722
- Official PDF: https://openairdocs.org/files/sha256/fa/c8/fac8d83d3b1b5e70a0177ad9e949309647520883354a7d055278547beda59fb0 (from https://www.govinfo.gov/content/pkg/FR-2011-03-14/pdf/2011-5722.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/03/14/2011-5722/airworthiness-directives-bombardier-inc-model-cl-600-2c10-regional-jet-series-700-701-and-702-model
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/3E5A817220BBAB6286257853004AF260.0001
- Page: https://openairdocs.org/proposed/FAA-2011-0159

## 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:

An inspection by the vendor revealed that a number of Rubber Bull Gears (RBG) in the Horizontal Stabilizer Trim Actuator (HSTA) of the CL-600-2C10, CL- 600-2D15 and CL-600-2D24 aeroplanes were installed with a wheel material hardness out of specification. This non-conformity has a direct impact on the HSTA life limit. The teeth of these non- conformant RBGs could break and in extreme cases, could lead to uncontrolled HSTA movement without the ability to re-trim the aeroplane. If not corrected, this condition could result in a difficulty to control the pitch and subsequent loss of the aeroplane.

* * * * *

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

## Notices in this docket

- Mar 14, 2011: Notice of proposed rulemaking (NPRM). (first notice), FR document 2011-5722, comments due Apr 28, 2011 (https://www.federalregister.gov/documents/2011/03/14/2011-5722/airworthiness-directives-bombardier-inc-model-cl-600-2c10-regional-jet-series-700-701-and-702-model)

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