# Airworthiness Directives; MT-Propeller Entwicklung GMBH Models MTV-9-B-C and MTV-3-B-C Propellers
> **Rule** · Final rule; request for comments. · Published 1999-07-08 · Effective 1999-07-23 · 64 FR 36777
## Document
- **Document number:** 99-16745
- **Category:** airworthiness
- **Manufacturer:** MT-Propeller Entwicklung GMBH Models MTV-9-B-C and MTV-3-B-C
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 64 FR 36777
- **Publication date:** 1999-07-08
- **Effective date:** 1999-07-23
- **FAA docket:** Docket No. 99-NE-35-AD
## Abstract

This amendment adopts a new airworthiness directive (AD) that is applicable to MT-Propeller Entwicklung GMBH Models MTV-9-B-C and MTV-3-B-C propellers. This action requires initial and repetitive inspections of Torx head blade root lag screws for torque values and breakage, and, if any screws are found broken or with insufficient torque, replacement of all screws with new lag screws. In addition, this AD requires replacement of certain model Torx head blade root lag screws with improved, hexagonal head blade root lag screws. This amendment is prompted by reports of broken Torx head blade root lag screws. The actions specified in this AD are intended to prevent blade root lag screw breakage, which could result in propeller blade separation and loss of control of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/07/08/99-16745/airworthiness-directives-mt-propeller-entwicklung-gmbh-models-mtv-9-b-c-and-mtv-3-b-c-propellers)
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