# AD 77-06-04: Tail Rotor Assembly

- Type: Airworthiness directive
- Status: Current
- Products: Enstrom Helicopter Corporation, The 280C, F-28C, 280C and F-28C
- Effective: March 31, 1977
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-2855
- Registered aircraft: 94 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/09C99AB1D20DF06E86256A38004DAAE4.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/77-06-04

## The airworthiness directive

77-06-04 ENSTROM: Amendment 39-2855. Applies to Enstrom Model F28C helicopters with serial numbers 364, 367, 373 and 374 and Model 280C with serial numbers 1007, 1020, 1060, 1062, 1065 certificated in all categories.

Before further flight, unless already accomplished, remove from service the tail rotor assembly P/N 28-150000-3 and replace with an airworthy assembly which has been assembled using forged blade grip fittings P/N 28-150013-11.

The removed tail rotor assembly should be returned to Enstrom Helicopter Corporation, Menominee, Michigan 49858.

This amendment becomes effective March 31, 1977, to all persons except those to whom it was made effective earlier by air mail letter dated March 2, 1977.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS H1CE](https://openairdocs.org/tcds/H1CE): The Enstrom Helicopter Corporation; names 2 of 14 models: 280C, F-28C

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 94 (94 by airframe model, 0 by engine model)
- Makers: Enstrom Helicopter 48, Enstrom 46

Models with the most aircraft:

- [Enstrom Helicopter 280C](https://openairdocs.org/model/enstrom-helicopter-280c): 48 aircraft (airframe model)
- [Enstrom F-28C](https://openairdocs.org/model/enstrom-f-28c): 46 aircraft (airframe model)

All 2 models: https://openairdocs.org/ad/77-06-04/models.md
Every aircraft: https://openairdocs.org/ad/77-06-04/aircraft.md

Its text cites no advisory circulars or STCs.

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