# AD 77-02-03: Stage 4 Turbine Buckets

- Type: Airworthiness directive
- Status: Current
- Products: General Electric CT64-820-4
- Effective: February 9, 1977
- Superseded by: Nothing supersedes this AD
- Product type: Engine
- Amendment: 39-2809
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/89659ACC3A3350CB8625685B005CB309.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/77-02-03

## The airworthiness directive

77-02-03 GENERAL ELECTRIC COMPANY: Amendment 39-2809. Applies to all General Electric Company CT64-820-4 model turboprop engines.

Compliance required within the next 100 hours time in service after the effective date of this AD, unless already accomplished.

To prevent the possibility of overstressing the Stage 4 turbine buckets, the engine output shaft overspeed limit is reduced from 1512 rpm to 1450 rpm. The original limit is given in Note 2 of Type Certificate Data Sheet E13EA-10, dated February 15, 1976.

This amendment becomes effective February 9, 1977.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS E13EA](https://openairdocs.org/tcds/E13EA): General Electric Company; names 1 of 1 models: CT64-820-4

## Registered aircraft it may apply to (OpenAirDocs)

No registered aircraft matched the models it names.

Its text cites no advisory circulars or STCs.

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