# STC SA7788SW-D

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: S-TEC Corporation, United States
- Description: Installation of S-TEC yaw damper system, model ST-401.
- Applied: January 11, 1991
- Status date: April 25, 1995
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A7CE](https://openairdocs.org/tcds/A7CE)
- Certificate PDF: https://openairdocs.org/files/sha256/4d/dd/4dddda9b70c862295217b319504231c18d433415277c74c2bef8a1523fd0aafd
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/90CC1265C26878CF85256CC20056A490.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA7788SW-D

## ADs that name it (0)

None.

## Approved models (2)

- The Cessna Aircraft Company 414A ([TCDS A7CE](https://openairdocs.org/tcds/A7CE))
- The Cessna Aircraft Company 421C ([TCDS A7CE](https://openairdocs.org/tcds/A7CE))

## What the certificate says

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

Brind Sams a 2 ma Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number SA7788SW-D This certificate issued to: S-TEC Corporation 946 Pegram Mineral Wells, Texas 76067 Port 3 of the CiVil Air Regulations Original Product -Type Contificater Numbon: AICE Make: CESSNA Model: 414А and 421С Description of Type Design Change:

Installation of S-TEC Yaw Damper System, Model ST-401, according to Bulletin No.

501, Revision 1, dated 4-05-95 and Master Drawing List No. 92532, Revision A, dated 4-05-95 or later FAA Approved revisions of the above data (28 Volt System).

1. FAA/DAS Approved Airplane Flight Manual Supplement, P/N 89907, dated 1-23-91 is required for Cessna Model 414A or later FAA Approved revisions of the above supplement.

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

Thomas DAS Statt Coordinator, DAS S Sw (Title) 17 PAR FOR 8110-2 (10-68)

Aniced Stares of Suerica Department of Transportation Federal Aviation Administration Supplemental Type Certificate (Continuation Sheet) Number: SA77885W-D, Revision 1 Limitations and Conditions: (con't.)

2. FAA/DAS Approved Pilot's Operating Handbook and/or Airplane Flight Manual Supplement, P/N 891162, dated 4-25-95 is required for Cessna Model 421C 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.

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 and streel) (Cil. State, and 21P code ) Extent of Authority (if licensing agreement):

Date of Transfer: _ Signature of grantor (In ink):

## Every issue (1)

- April 25, 1995: Amended, Current. [certificate](https://openairdocs.org/files/sha256/4d/dd/4dddda9b70c862295217b319504231c18d433415277c74c2bef8a1523fd0aafd)

---
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.