# STC SA257CH

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Elliott Aviation Technical Products, United States
- Description: Increases the cruise interstage turbine temperature (ITT) limit to 695 degrees centrigrade. (C90 WITH PRATT & WHITNEY PT6A-21 ENGINES)
- Status date: September 27, 1994
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 3A20](https://openairdocs.org/tcds/3A20)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/28BC614930A6506685256CC200016007.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA257CH

## ADs that name it (0)

None.

## Approved models (1)

- Raytheon Aircraft Company C90 ([TCDS 3A20](https://openairdocs.org/tcds/3A20))

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