# STC SA4-683

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Atlantic Coast Sea Planes LLC, United States
- Description: Installation of auxiliary fuel tanks in outboard wing sections.
- Applied: April 2, 1962
- Status date: March 7, 2008
- Product: Aircraft, Single-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 654](https://openairdocs.org/tcds/654)
- Certificate PDF: https://openairdocs.org/files/sha256/aa/44/aa44b079207622bfa5839115d921159952bda094acecbd639ca5958d70a5dbba
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/459ABF9779993AF98625742B006B10B0.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA4-683

## ADs that name it (0)

None.

## Approved models (2)

- Grumman American Aviation Corporation G-21 ([TCDS 654](https://openairdocs.org/tcds/654))
- Grumman American Aviation Corporation G-21A ([TCDS 654](https://openairdocs.org/tcds/654))

## 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.

Number SA4-683

This certificate, issued to Atlantic Coast Seaplanes LLC 3623 N. Elm Street, Suite 200 P. 0. Box 41027 Greensboro, NC 27455

Aeronautical Bulletin 7A..

Original Product⎯Type Certificate Number: 654 Make: Grumman Model: G-21 and G-21A

Description of the Type Design Change: Installation of auxiliary fuel tanks in the outboard wing section in accordance with FAA sealed McKinnon Enterprise’s Master Drawing List No. 1, “Outer Wing Tank Installation”, dated January 16, 1962, or later FAA approved revision.

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 these models on which other previously approved modifications are incorporated unless it is determined that the relationship between this change and any 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 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: April 2, 1962 Date reissued: 06/06/84; 09/04/98; 05/05/00; 09/27/07 Date of issuance: March 20, 1972 Date amended: 03/07/08

(Signature)

Acting Manager, Seattle Aircraft Certification Office (Title)

## Every issue (2)

- March 7, 2008: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/aa/44/aa44b079207622bfa5839115d921159952bda094acecbd639ca5958d70a5dbba)
- September 27, 2007: Reissued, Historical. [certificate](https://openairdocs.org/files/sha256/9b/f4/9bf4bb51d315d1bad60bfc3a398b9152aa1aaa4a1938c75e15ad2e3d7f9c31a5)

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