# STC SA09163AC-D

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: S-TEC Corporation, United States
- Description: Installation of S-TEC System 40/50 single and two axis automatic flight guidance systems, Model ST-634-40/50.
- Applied: August 12, 1996
- Status date: August 16, 1996
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 2A4](https://openairdocs.org/tcds/2A4)
- Certificate PDF: https://openairdocs.org/files/sha256/b4/ef/b4ef15efad7f17d349d672f871641f8200e2476cbe0cb8a089b5ccf5a5b70138
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B384B2F30790338B85256CC1007F39F9.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA09163AC-D

## ADs that name it (0)

None.

## Approved models (1)

- Twin Commander Aircraft LLC 680-E ([TCDS 2A4](https://openairdocs.org/tcds/2A4))

## What the certificate says

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

Hairol Scare of Sacrica Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number: SA09163AC-D This certificate issued to: S-TEC Corporation 946 Pegram Mineral Wells, TX 76067 Port 3 of the CIVIl Air Regulations Original Product -Typo Contificate Numbon: 2A4 Make: Twin Commander Model: 680-E Description of Type Design Change:

Installation of S-TEC System 40/50 Single and Two Axis Automatic Flight Guidance Systems, Model ST-634-40/50, according to Bulletin No. 734, dated 8-09-96 and Master Drawing List No. 92946, dated 8-09-96 or later FAA Approved revisions of the above data (28 Volt System).

1. FAA/DAS Approved Pilot's Operating Handbook and/or Airplane Flight Manual Supplement, P/N 891295, dated 8-16-96 is required for Twin Commander Model 680-E for S-TEC System 40 or later FAA Approved revisions of the above supplement.

(See Continuation Sheet, Page 2, a part of this STC.)

Thomas DAS Staff Coordinator, DAS 5 SW (Title)

47.

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate (Continuation Sheet) Number: SA09163A -0 Limitations and Conditions: (con't.)

2. FAA/DAS Approved Pilot's Operating Handbook and/or Airplane Flight Manual Supplement, - System or later proved revisions of me de odel 680-E for S-TEC System supplement.

3. Compatibility of this modification with other previously approved modifications must be determined by the installer.

**47 PAGE 2 OF 2 PAGES**

TRANSFER ENDORSEMENT Transfer the ownership of Supplemental Type Certificate Number to (Name of transferee) (Address of transferee) (Number and street) (City, State, and ZIP code) from (Name of grantor) (Print or type) (Address of grantor) (Number & street) (CIFY, State, and ZIP code) Extent of Authority (if licensing agreement):

Signature of grantor (In ink):

## Every issue (1)

- August 16, 1996: Issued, Current. [certificate](https://openairdocs.org/files/sha256/b4/ef/b4ef15efad7f17d349d672f871641f8200e2476cbe0cb8a089b5ccf5a5b70138)

---
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.