# STC SA680SW

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Century Flight Systems Inc, United States
- Description: Installation of Mitchell automatic flight system model AK221 consisting of Century III autopilot with optional automatic pitch trim, radio coupler, and glide slope coupler.
- Applied: July 12, 1966
- Status date: June 25, 1984
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 6A1](https://openairdocs.org/tcds/6A1)
- Certificate PDF: https://openairdocs.org/files/sha256/5d/2f/5d2f6376f995114fce8637554fae69faf3605193854fd2f4de208c83c1fb1245
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/01B7B3030E2DD76485256CC20056A025.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA680SW

## ADs that name it (1)

- [AD 70-15-18](https://openairdocs.org/ad/70-15-18): Automatic Pilot and Automatic Aileron Stabilizer Instruments · Mitchell Industries Auto Pilot Systems Instruments. Effective Aug 31, 1970. Cited in the text

## Approved models (4)

- Twin Commander Aircraft LLC 500-A ([TCDS 6A1](https://openairdocs.org/tcds/6A1))
- Twin Commander Aircraft LLC 500-B ([TCDS 6A1](https://openairdocs.org/tcds/6A1))
- Twin Commander Aircraft LLC 500-S ([TCDS 6A1](https://openairdocs.org/tcds/6A1))
- Twin Commander Aircraft LLC 500-U ([TCDS 6A1](https://openairdocs.org/tcds/6A1))

## What the certificate says

This is OCR from the scanned FAA certificate. OCR can misread letters and numbers.

Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number: SA68054 This certificate issued to: Century Flight Systems, Inc.

F.M. 1195 P. O. Box 610 Mineral Wells, IX 76067 Purt 3 of the CIV11 AIr Regulations.

Original Product -Type Certificate Number: 6A1 Make: Aero Commander Model: 500A, 500B, 500S, and 500U Description of Type Design Change: Installation of Mitche11 Automatic Flight Systen Model AK221 consisting of Century III Autopilot with optional Automatic Pitch Trim, Radio Coupler and Glide Slope Coupler per Bulletin No. 329, Revision 4, dated 8-5-70;

and optional Mitchell Radio Coupler 1C388-3 per Bulletin No. 611, dated 4-16-74 and Master Drawing List No. 87A708, Revision A, dated 4-16-74.

The following FAA Approved Airplane Flight Manual Supplements are required;

1. Supplements date 8-18-66 for Aero Commander Model 500A, 500B, or 500U.

2. Supplements dated 7-31-68 for Aero Commander Model 500S.

3. Supplement dated 4-16-74 for Radio Coupler, his certificate and the supporling dals whic Compatibility of this modification with other previously approved modifications must be determined by the installer: thelasis draphrvalshullrernaininellertuntilsur vendered, suspended, revoked, or a termination date is otherwise established by the Advinia tral. r of the Federal Aviation Administration .

Date of Application: July 12, 1966 Juk missered: 7-31-68; 9-24-70; 4-16-74;

6-25-84, Revision 4 Date of Issuance: August 18, 1966 'Sale unvended:

EDERAL AVIATIO By Direction of the Administrator Don P. Watson I (Signature) POMINISTRATO Manager terraft Certification Division (Title)

47.

TRANSFER ENDORSEMENT Transfer the ownership of Supplemental Type Certificate Number to (Name of transferee).

(Address of transferee) (Number and street) (CIl), State, and 21P code ) from (Name of grantor) (Print or type) (Address of grantor) (sumost and sirrel) (City, State, and 218 code) Extent of Authority (if licensing agreement):.

Signature of grantor (In ink): - 80-582-090

## Every issue (1)

- June 25, 1984: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/5d/2f/5d2f6376f995114fce8637554fae69faf3605193854fd2f4de208c83c1fb1245)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.