# STC SA09156AC-D

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: S-TEC Corporation, United States
- Description: Installation of S-TEC System 55/55X Two Axis Automatic Flight Guidance System, Model ST-633,
- Applied: May 29, 1996
- Status date: October 18, 2001
- Product: Aircraft, Single-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 3A12](https://openairdocs.org/tcds/3A12)
- Certificate PDF: https://openairdocs.org/files/sha256/b3/fe/b3fe84f44627a4b3b9fa31128049782ef0ff6c525a6514b9c55992e4f08e1ecb
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/39192412EA7E868F85256CC1007F39F2.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA09156AC-D

## ADs that name it (0)

None.

## Approved models (4)

- Cessna Aircraft Company 172 ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172A ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172B ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172C ([TCDS 3A12](https://openairdocs.org/tcds/3A12))

## What the certificate says

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

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number: SA09156AC-D This certificate issued to: S-TEC Corporation One S-TEC Way Mineral Wells Municipal Airport Mineral Wells, TX 76067-9236 Part 3 of the Cind In Regulations.

Original Product I ype Certificate Number: 3A12 Make: Cessna Model: 172, 172A, 172B, and 172C Description of Type Design Change:

Installation of S-TEC System 55/55X Two Axis Automatic Flight Guidance System, Model ST-633, according to Bulletin No. 733, Revision 3, dated 10-18-01 and Master Drawing List No. 92938, Revision C, dated 10-18-01 or later FAA Approved revisions of the above data (14 Volt System).

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

If the holder agrees to permit another person to use this certificate to alter the product, the holder shall give the other person written evidence of that permission.

Date of Application: 5-29-96 Date Reissued:

Date of Issuance: 6-10-96 Date Amended: 10-18-01 By Direction of the Administrator FEDERAL AVIATION niel Ki (Signature) TOMNISTRATIO Michael Keirnan DAS Staff Coordinator, DAS 5 SW (Title) ble by a fine of not exceeding $1,000, or imprisonment not exceeding 3 years, or both.

FAA Form 8110-2(10 This certificate may be t sferred in accordance with PAR 21.47.

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate (Continuation Sheet) Number: SA09156AC-D Limitations and Conditions: (con't.)

FAA/DAS Approved Supplemental Flight Manual, P/N 891271, dated 6-10-96 is required for Cessna Models 172, 172A, 172B, and 172C or later FAA Approved revisions of the above supplement.

2. FAA/DAS Approved Supplemental Flight Manual, P/N 891271, Revision 1, dated 10-18-01 is required for Cessna models 172, 172A, 172B, and 172C for S-TEC System 55/55X or later FAA Approved revisions of the above supplement.

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

PAA Form 8110-2-1 (10-69) Page 2 of 2

The FAR will reissue the certificate in the name of the transferee and forward it to him.

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) (City, State, and ZIP code) Extent of Authority (if licensing agreement):

Signature of grantor (In ink):

## Every issue (1)

- October 18, 2001: Amended, Current. [certificate](https://openairdocs.org/files/sha256/b3/fe/b3fe84f44627a4b3b9fa31128049782ef0ff6c525a6514b9c55992e4f08e1ecb)

---
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.