# Proposed AD FAA-2021-0656: De Havilland Aircraft of Canada Limited (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2021-23-02
- Products: De Havilland Aircraft of Canada
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: August 12, 2021, 86 FR 44324
- Comments due: September 27, 2021
- Became: [AD 2021-23-02](https://openairdocs.org/ad/2021-23-02)
- Docket: FAA-2021-0656 (https://www.regulations.gov/docket/FAA-2021-0656, where comments are filed)
- Project: MCAI-2021-00394-T
- FR document: 2021-16935
- Official PDF: https://openairdocs.org/files/sha256/52/15/5215c4afe1bb29c20fcda592b29e3147e4a1e5f8dea5c93fd52edd41572af433 (from https://www.govinfo.gov/content/pkg/FR-2021-08-12/pdf/2021-16935.pdf)
- Federal Register: https://www.federalregister.gov/documents/2021/08/12/2021-16935/airworthiness-directives-de-havilland-aircraft-of-canada-limited-type-certificate-previously-held-by
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/7BE772013913B93F8625872F00776EF8.0001
- Page: https://openairdocs.org/proposed/FAA-2021-0656

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for certain De Havilland Aircraft of Canada Limited Model DHC-8-401 and -402 airplanes. This proposed AD was prompted by reports of loss of hydraulic fluid and annunciation of the check fire detect light. This proposed AD would require doing a detailed visual inspection for chafing and proper clearance of the left-hand (LH) and right-hand (RH) main landing gear (MLG) primary zone advanced pneumatic detector (APD) sensing lines, the hydraulic tube assemblies, and the surrounding structure, and doing all applicable corrective actions. The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Aug 12, 2021: Notice of proposed rulemaking (NPRM). (first notice), FR document 2021-16935, comments due Sep 27, 2021 (https://www.federalregister.gov/documents/2021/08/12/2021-16935/airworthiness-directives-de-havilland-aircraft-of-canada-limited-type-certificate-previously-held-by)

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