# Airworthiness Directives; Enstrom Helicopter Corporation Model F-28A, F-28C, F-28F, TH-28, 280, 280C, 280F, 280FX, 480, and 480B Helicopters
> **Rule** · Final rule. · Published 2007-08-28 · Effective 2007-10-02 · 72 FR 49177
## Document
- **Document number:** E7-16770
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 72 FR 49177
- **Publication date:** 2007-08-28
- **Effective date:** 2007-10-02
- **FAA docket:** Docket No. FAA-2006-26771
## Abstract

This amendment adopts a new airworthiness directive (AD) for Enstrom Helicopter Corporation (Enstrom) Model F-28A, F-28C, F-28F, TH- 28, 280, 280C, 280F, 280FX, 480, and 480B helicopters that requires determining the installation dates for each main rotor push-pull control rod (push-pull rod), inspecting the push-pull rods for corrosion, replacing any push-pull rod which has corrosion that is severe enough to cause pitting, or has visible moisture inside the rod, and repairing each push-pull rod that has corrosion but no pitting. This amendment is prompted by one reported incident in which the helicopter pilot encountered severe in-flight vibration due to the failure of a push-pull rod, requiring an emergency landing. The actions specified by this AD are intended to detect corrosion and prevent failure of a push-pull rod, and subsequent loss of control of the helicopter.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2007/08/28/E7-16770/airworthiness-directives-enstrom-helicopter-corporation-model-f-28a-f-28c-f-28f-th-28-280-280c-280f)
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