# STC SA3420SW-D

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Century Flight Systems Inc, United States
- Description: Mitchell automatic flight system AK921 consisting of Century III autopilot with optional radio coupler and glide slope coupler.
- Status date: August 23, 1983
- Product: Aircraft, Single-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A20CE](https://openairdocs.org/tcds/A20CE)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/3B08E78271A6434385256CC2000A97E4.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA3420SW-D

## ADs that name it (0)

None.

## Approved models (1)

- The Cessna Aircraft Company 177RG ([TCDS A20CE](https://openairdocs.org/tcds/A20CE))

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