# STC SA09228AC-D

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: S-TEC Corporation, United States
- Description: Installation of S-TEC System 30 ALT Altitude Hold System Model ST-686
- Applied: May 30, 1997
- Status date: June 4, 1997
- Product: Aircraft, Single-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 3A12](https://openairdocs.org/tcds/3A12)
- Certificate PDF: https://openairdocs.org/files/sha256/76/16/7616efdf812ba00b8c1a9f30807a858b1806bcf88261ef13bdcebc634f63010a
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/18C6371FFD14AA9585256CC1007F3A2C.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA09228AC-D

## ADs that name it (0)

None.

## Approved models (12)

- 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))
- Cessna Aircraft Company 172D ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172E ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172F (USAF T-41A) ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172G ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172H (USAF T-41A) ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172I ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172K ([TCDS 3A12](https://openairdocs.org/tcds/3A12))
- Cessna Aircraft Company 172L ([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: SA09228AC-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 therefor as specifed hereon meets the aivorthiness regurements of Part 3 of the Civil stir Regulations.

Original Product I ype Certificate Number: 3A12 Make: Cessna Model: 172, 172A, 172B, 172C, 172D, 172E, 172F, 172G, 172H, 1721, 172K, AND 172L Descriplion of 9 ype Design Change:

Installation of S-TEC System 30 ALT Altitude Hold System, Model ST-686, according to Bulletin No. 786, dated 5-28-97 and Master Drawing List No. 92999, dated 5-28-97 or later FAA Approved revisions of the above data (14 Volt System).

Also eligible on the Above Models When Modified Per STC SA420CE (Lycoming Engine 0-360- AID, 180 H.P.)

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

Date of Application: 5-30-97 Date Reissued:

Date of Issuance: 6-04-97 Date Amended:

FEDERAL AVIATION TOMINISTRATO DAS Staff Coordinator, DAS 5 SW William J. Thomas (Title)

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate (Continuation Sheet) Number: SA09228 AC-D Limitations and Conditions: (con't.)

2. FAA/DAS Approved Supplemental Flight Manual, P/N 891406, dated 6-04-97 is required for Cessna Models 172, 172A, 172B, and 172C And The Above Models When Modified Per STC SA420CE (Lycoming Engine 0-360-A1D, 180 H.P.) or later FAA Approved revisions of the above supplement.

revisions of the above supplement.

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

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

The FAA will reissue the certificate in the name of the transferee and fotward 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 codel Exten: of Authority (if licensing agreement):

Signature of grantor (In ink):

## Every issue (1)

- June 4, 1997: Issued, Current. [certificate](https://openairdocs.org/files/sha256/76/16/7616efdf812ba00b8c1a9f30807a858b1806bcf88261ef13bdcebc634f63010a)

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