# STC SA3-126

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: D'Shannon Products Ltd., United States
- Description: Lycoming O-340-A1A engine and Hartzell HC-82XG-1DB/8433-12 propeller.
- Status date: July 14, 2011
- Product: Aircraft, Single-Engine
- Certification basis: Part 3, Part 21
- Data sheets: [TCDS 3A12](https://openairdocs.org/tcds/3A12)
- Certificate PDF: https://openairdocs.org/files/sha256/a6/45/a645f74aa23f7e04d2baba9c755810dcc01806cf130c8eca5b2f9042ee514028
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/6F81205AE5AE5A6C862578EF0049821E.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA3-126

## ADs that name it (2)

- [AD 82-07-02](https://openairdocs.org/ad/82-07-02): Engine Crankcase Breather · Lycoming O-360-A1A engine and Hartzell HC-C2YK-1B/7666A-2… (Avcon Industries STC SA1324CE or 14 others). Effective Apr 8, 1982. Named in the applicability
- [AD 69-15-03](https://openairdocs.org/ad/69-15-03): Muffler Assembly · Lycoming O-320-A1A, A1B, A3A, A3B or Lycoming O-320-B1A, B1B… (D'Shannon Products STC SA135CE or 8 others). Effective Aug 20, 1969. Named in the applicability

## Approved models (1)

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

## What the certificate says

Read from the PDF's text layer, without the form's printed wording; the layout is lost and the order can differ. The PDF is the record.

This certificate issued to

Part 3 of the Civil Air Regulations.

1. Lycoming O-340-A1A engine, together with the standard Lycoming accessories, replaces the Continental C-145 originally installed;

2. Constant-speed Hartzell propeller, HC-82XG-1DB/8433-12, replaces the fixed-pitch McCauley propeller. Installation must be made in accordance with Doyn Aircraft “Kit Installation” Drawing No. 1099.

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

D’Shannon Products, Ltd.

1309 County Road 134 Buffalo, MN 55313 3A12 Make : Cessna Model : 172 Date of application :

Date of issuance : November 15, 1957

Date reissued : 1/25/66; 5/17/78; 5/12/11; 7/14/11

( Signature) Melvin D. Taylor Manager Atlanta Aircraft Certification Office

( Title)

## Every issue (2)

- July 14, 2011: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/a6/45/a645f74aa23f7e04d2baba9c755810dcc01806cf130c8eca5b2f9042ee514028)
- May 12, 2011: Reissued, Historical. [certificate](https://openairdocs.org/files/sha256/b6/55/b6551735ced5c3bc4b3fac6550ee6565a495c3dc84daa165fe7ea34b339e3779)

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