# STC SA5684NM

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: McHugh Aviation Inc, United States
- Description: Installation of Lycoming GSO/IGSO-480 engine; Hartzell HC-A3V20 propeller; new nacelle and engine mount; modified front and rear spar and aft firewall; and associated systems.
- Applied: November 15, 1990
- Status date: June 25, 2004
- Product: Aircraft, Single-Engine
- Certification basis: Part 3, Part 21
- Data sheets: [TCDS A-769](https://openairdocs.org/tcds/A-769)
- Certificate PDF: https://openairdocs.org/files/sha256/10/62/10629c6d43328e6286b6ddb8014eb2b910a40b1d882322e760310c6ba9f14a53
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/C216F9C23AA3E3BD86256EE50067CAE5.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA5684NM

## ADs that name it (0)

None.

## Approved models (1)

- Sky Enterprises Inc. RC-3 ([TCDS A-769](https://openairdocs.org/tcds/A-769))

## What the certificate says

Some pages are OCR from the scanned FAA certificate. OCR can misread letters and numbers.

Number: SA5684NM

This certificate issued to: McHugh Aviation, Inc.

3763 Image Drive Anchorag e, AK 99504

Part 3 of the Civil Air Regulations.

Original Product Type Certificate Number: A-769 Make: STOL Amphibian Corporation (REPUBLIC) Model: RC-3

Description of Type Design Change: Installation of Lycoming GSO/IGSO-480 engine;

Hartzell HC-A3V20 propeller; new nacelle and engine mount; modified front and rear spar and aft firewall; and associated systems in accordance with Simuflight, Seattle, Drawing List No. SS1000, Rev. G of September 13, 1991, or later FAA approved revision. This change includes an increased takeoff gross weight to 3250 pounds.

Limitations and Conditions: Approval of this change in type design applies to the above model aircraft only. This approval should not be extended to other aircraft of this model on which other previously approved modifications are incorporated unless it is determined that the relationship between this change and any of those other previously approved modifications, including changes in type design, will introduce no adverse effect upon the airworthiness of that aircraft. A copy of this Certificate, its Continuation Sheet, and Airplane Flight Manual supplement of February 18, 1992, or later FAA approved revision, must be maintained as part of the permanent records for the modified aircraft.

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: November 15, 1990 Date reissued: June 25, 2004 Date of Issuance: February 19, 1992 Date amended: June 25, 2004

(Signature) Acting Manager, Seattle Aircraft Certification Office (Title)

## Every issue (1)

- June 25, 2004: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/10/62/10629c6d43328e6286b6ddb8014eb2b910a40b1d882322e760310c6ba9f14a53)

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