# STC SA00354AT

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: National Flight Services, Inc, United States
- Description: Installation of Garrett TPE331-5-511 engines.
- Status date: October 20, 1999
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 2A4](https://openairdocs.org/tcds/2A4)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FC80EF39FC657D0485256CC1007DC8C2.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA00354AT

## ADs that name it (0)

None.

## Approved models (4)

- Twin Commander Aircraft Corporation 690A ([TCDS 2A4](https://openairdocs.org/tcds/2A4))
- Twin Commander Aircraft Corporation 690B ([TCDS 2A4](https://openairdocs.org/tcds/2A4))
- Twin Commander Aircraft Corporation 690C ([TCDS 2A4](https://openairdocs.org/tcds/2A4))
- Twin Commander Aircraft Corporation 690D ([TCDS 2A4](https://openairdocs.org/tcds/2A4))

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