# STC SA09225AC-D

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: S-TEC Corporation, United States
- Description: Installation of S-TEC System 20/30 Single and Two Axis Automatic Flight Guidance Systems Model ST-685-20/30
- Applied: May 21, 1997
- Status date: May 23, 1997
- Product: Aircraft, Small Airplane
- Certification basis: Part 21
- Data sheets: [TCDS 3A17](https://openairdocs.org/tcds/3A17)
- Certificate PDF: https://openairdocs.org/files/sha256/17/f0/17f06798611e53ed1321e1114456191efb43ea113f48f15699e50bb1ec67e724
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B43511C29DD628F685256CC1007F3A2A.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA09225AC-D

## ADs that name it (0)

None.

## Approved models (8)

- Cessna Aircraft Company 175 ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company 175A ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company 175B ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company 175C ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company R172E ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company R172F ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company R172G ([TCDS 3A17](https://openairdocs.org/tcds/3A17))
- Cessna Aircraft Company R172H ([TCDS 3A17](https://openairdocs.org/tcds/3A17))

## 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 5A09225 AC-D This certificate issued to: S-TEC Corporation One S-TEC Way Mineral Wells Municipal Airport Mineral Wells, TX 76067-9236 Certifies that the change in the type design for the following product with the limitations and conditions thorofor as specified horeon meets the aivorthiness segurements of Part 3 of the Civil In Regulations.

Original Product Type Certifcate Number: 3A17 Make: CESSNA Model: R172E, R172F, R172G, RI72H, 175, 175A, 175B, AND 175C Description of 9 ype Design Change;

Installation of S-TEC System 20/30 Single and Two Axis Automatic Flight Guidance Systems, Model ST-685-20/30, according to Bulletin No. 785, dated 5-20-97 and Master Drawing List No. 92997, dated 5-20-97 or later FAA Approved revisions of the above data (14 Volt System).

FAA/DAS Approved Supplemental Flight Manual, P/N 891392, dated 5-23-97 is required for Cessna Models R172E, R172F, R172G, and R172H for S-TEC System 20 or later FAA Approved revisions of the above supplement.

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

Date of Application: 5-21-97 Date Reissued:

Date of Issuance: 5-23-97 Date Amended:

By Direction of the Administrator Ween There TOMINSTRATO William J. Thomas DAS Staff Coordinator, DAS 5 SW (Title)

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate (Continuation Sheet) Number: SA09225 AC-D Limitations and Conditions: (con't.)

2. FAA/DAS Approved Supplemental Flight Manual, P/N 891393, dated 5-23-97 is required for Cessna Models 175, 175A, 175B, and 175C for S-TEC System 20 or later FAA Approved revisions of the above supplement.

3. FAA/DAS Approved Supplemental Flight Manual, P/N 891398, dated 5-23-97 is required for Cessna Models R172E, R172F, R172G, and R172H for S-TEC System 30 or later FAA Approved revisions of the above supplement.

4. FAA/DAS Approved Supplemental Flight Manual, P/N 891399, dated 5-23-97 is required for Cessna Models 175, 175A, 175B, and 175C for S-TEC System 30 or later FAA Approved revisions of the above supplement.

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

FAA Form 0110-2-1(10-69) Page 2 of 2

The FAA will reissue the certificate in the name of the transfetee and forward it to tams

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 codel Extent of Authority (if licensing agreement):

Signature of grantor (In ink) :

## Every issue (1)

- May 23, 1997: Issued, Current. [certificate](https://openairdocs.org/files/sha256/17/f0/17f06798611e53ed1321e1114456191efb43ea113f48f15699e50bb1ec67e724)

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