# Airworthiness Directives; GE Aircraft Engines CT7 Series Turboprop Engines
> **Rule** · Final rule; request for comments. · Published 1998-01-13 · Effective 1998-01-28 · 63 FR 1901
## Document
- **Document number:** 98-71
- **Category:** airworthiness
- **Manufacturer:** GE
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 63 FR 1901
- **Publication date:** 1998-01-13
- **Effective date:** 1998-01-28
- **FAA docket:** Docket No. 97-ANE-41-AD
## Abstract

This amendment supersedes an existing airworthiness directive (AD), applicable to GE Aircraft Engines (GE) CT7 series turboprop engines, that currently requires eddy current inspection (ECI) of disk holes of stage 1 and 2 gas generator turbine (GGT) disks for cracks, and, if necessary, replacement with serviceable parts. This amendment increases the initial cyclic compliance threshold while decreasing the calendar time for performing the ECI. This amendment is prompted by corrections to the applicable alert service bulletin (ASB) serial number (S/N) tables. The ASB contained S/Ns which appeared in more than one table creating confusion over which cyclic limit applied to each S/ N. The actions specified by this AD are intended to prevent a stage 1 or 2 GGT disk failure, which could result in an uncontained engine failure and damage to the aircraft.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1998/01/13/98-71/airworthiness-directives-ge-aircraft-engines-ct7-series-turboprop-engines)
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