# Airworthiness Directives; Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series Aircraft Limited Partnership (CSALP); Bombardier, Inc.) Airplanes
> **Rule** · Final rule. · Published 2021-03-22 · Effective 2021-04-26 · 86 FR 15089
## Document
- **Document number:** 2021-05583
- **Category:** airworthiness
- **Manufacturer:** Airbus Canada Limited Partnership (Type Certificate Previously Held by C Series
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 86 FR 15089
- **Publication date:** 2021-03-22
- **Effective date:** 2021-04-26
- **FAA docket:** Docket No. FAA-2020-0971
## Abstract

The FAA is adopting a new airworthiness directive (AD) for certain Airbus Canada Limited Partnership Model BD-500-1A10 and BD-500- 1A11 airplanes. This AD was prompted by a report that threaded fuel couplings were incorrectly installed at final assembly and in service. This AD requires repetitive functional tests of the auxiliary power unit (APU) fuel feed line shroud, a general visual inspection of the APU fuel feed line shroud for any loose couplings; and tightening any loose couplings, which would terminate the repetitive functional tests. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2021/03/22/2021-05583/airworthiness-directives-airbus-canada-limited-partnership-type-certificate-previously-held-by-c)
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