# Proposed AD FAA-2021-0546: Hoffmann GmbH & Co. KG Propellers

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2021-23-17
- Products: Hoffmann
- Product type: Propeller
- Action: Notice of proposed rulemaking (NPRM).
- Published: July 6, 2021, 86 FR 35416
- Comments due: August 20, 2021
- Became: [AD 2021-23-17](https://openairdocs.org/ad/2021-23-17)
- Docket: FAA-2021-0546 (https://www.regulations.gov/docket/FAA-2021-0546, where comments are filed)
- Project: MCAI-2021-00387-P
- FR document: 2021-14271
- Official PDF: https://openairdocs.org/files/sha256/a5/76/a5766e957903f462731005abd3fa185def90fd8fc60b2d83b2ede759c7edeccf (from https://www.govinfo.gov/content/pkg/FR-2021-07-06/pdf/2021-14271.pdf)
- Federal Register: https://www.federalregister.gov/documents/2021/07/06/2021-14271/airworthiness-directives-hoffmann-gmbh-and-co-kg-propellers
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/498BCBB6E75C1A5B8625870A00792169.0001
- Page: https://openairdocs.org/proposed/FAA-2021-0546

## Summary

The FAA proposes to supersede Airworthiness Directive (AD) 2020-25-05, which applies to all Hoffmann GmbH & Co. KG (Hoffmann) model HO-V 72 propellers. AD 2020-25-05 requires amending the existing aircraft flight manual (AFM) with abnormal propeller vibration instructions. AD 2020-25-05 also requires visual inspection and non- destructive test (NDT) inspection of the propeller hub and, depending on the results of the inspections, replacement of the propeller hub with a part eligible for installation. AD 2020-25-05 also requires replacement of the propeller hub before exceeding 30 years since the date of manufacture. Since the FAA issued AD 2020-25-05, analyses of the inspection results showed that the 30-year life limit of the propeller hub is no longer needed. This proposed AD would retain certain requirements of AD 2020-25-05 and remove the 30-year life limit of the propeller hub. The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Jul 6, 2021: Notice of proposed rulemaking (NPRM). (first notice), FR document 2021-14271, comments due Aug 20, 2021 (https://www.federalregister.gov/documents/2021/07/06/2021-14271/airworthiness-directives-hoffmann-gmbh-and-co-kg-propellers)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.