# Proposed AD FAA-2010-0673: BAE Systems (Operations) Limited Model BAe 146 and Avro 146-RJ Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2011-11-06
- Products: BAE Systems
- Product type: Aircraft
- Action: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.
- Published: February 7, 2011, 76 FR 6575
- Comments due: March 24, 2011
- Became: [AD 2011-11-06](https://openairdocs.org/ad/2011-11-06)
- Docket: FAA-2010-0673 (https://www.regulations.gov/docket/FAA-2010-0673, where comments are filed)
- Project: 2009-NM-208-AD
- FR document: 2011-2610
- Official PDF: https://openairdocs.org/files/sha256/ef/d8/efd857d1677d29344ad8e612b78658782cc49f417a58575407caea36191a2966 (from https://www.govinfo.gov/content/pkg/FR-2011-02-07/pdf/2011-2610.pdf)
- Federal Register: https://www.federalregister.gov/documents/2011/02/07/2011-2610/airworthiness-directives-bae-systems-operations-limited-model-bae-146-and-avro-146-rj-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/DA925B6975CC85778625783000510516.0001
- Page: https://openairdocs.org/proposed/FAA-2010-0673

## Summary

We are revising an earlier NPRM for the products listed above. This action revises the earlier NPRM by expanding the scope. 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:

In June 2000, prompted by a crack found at the top of the Nose Landing Gear (NLG) oleo, BAE Systems (Operations) Ltd (BAE Systems) issued Inspection Service Bulletin (ISB) ISB.32-158. * * *

Later, as part of an accident investigation, the examination of a fractured NLG main fitting showed that M-D (Messier-Dowty) SB.146- 32-150 was not accomplished * * * BAE Systems determined that more NLG units could be similarly affected. * * *

Subsequently, investigation and analysis by M-D identified the need for a reduction of the inspection threshold and the repetitive inspection interval for the affected NLG units. * * *

* * * * *

* * * [I]nvestigation by M-D showed that if any undetected crack was present at the time of the embodiment of M-D SB 146-32-150, Part B or Part C, it could continue to grow while the NLG is in service and could lead to the failure of the main fitting and possible collapse of the NLG. * * * [B]AE Systems have received additional reports of cracked NLG main fittings. One operator reported a crack in a premodification main fitting. * * *

* * * * *

Undetected cracks could lead to failure of the NLG Main Fitting and collapse of the NLG.

* * * * *

The unsafe condition is cracking of the NLG, which could adversely affect the airplane's safe landing. The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

## Notices in this docket

- Jul 7, 2010: Notice of proposed rulemaking (NPRM). (first notice), FR document 2010-16519, comments due Aug 23, 2010 (https://www.federalregister.gov/documents/2010/07/07/2010-16519/airworthiness-directives-bae-systems-operations-limited-model-bae-146-and-avro-146-rj-airplanes)
- Feb 7, 2011: Supplemental notice of proposed rulemaking (NPRM); reopening of comment period., FR document 2011-2610, comments due Mar 24, 2011 (https://www.federalregister.gov/documents/2011/02/07/2011-2610/airworthiness-directives-bae-systems-operations-limited-model-bae-146-and-avro-146-rj-airplanes)

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