# STC SA221CH

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Duncan Aviation, United States
- Description: Installation of a Collins TCAS94 TCAS II system.
- Status date: July 1, 1994
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A27CE](https://openairdocs.org/tcds/A27CE)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/4500C8053441F86A85256CC200015B36.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA221CH

## ADs that name it (0)

None.

## Approved models (2)

- The Cessna Aircraft Company 501 ([TCDS A27CE](https://openairdocs.org/tcds/A27CE))
- The Cessna Aircraft Company 551 ([TCDS A27CE](https://openairdocs.org/tcds/A27CE))

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