# STC SH4-235

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Aetna Helicopters Inc, United States
- Description: Installed Franklin model 6V-335-A engine restricted to 200 hp.
- Applied: May 29, 1957
- Status date: June 28, 1957
- Product: Aircraft, Rotorcraft
- Certification basis: Part 21
- Data sheets: [TCDS H-1](https://openairdocs.org/tcds/H-1)
- Certificate PDF: https://openairdocs.org/files/sha256/f8/b7/f8b7e7e4e516472add7d57c9a9d19d29f4a88f35e510707a51e0e17cc893fb92
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BF9958AA94C9762D86257DF200598D8F.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SH4-235

## ADs that name it (0)

None.

## Approved models (1)

- Scotts-Bell 47 Inc 47G ([TCDS H-1](https://openairdocs.org/tcds/H-1))

## What the certificate says

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

FORM ACA-2417 U.S. DEPARTMENT OF COMMERCE Supplemental Type Certificate

1. NAME AND ADDRESS OF APPLICANT Aetna Helicopters Inc.

Etna, California

3. DESCRIPTION OF CHANGE Form Approved, Budget Bureau No. 41-R1823 INSTRUCTIONS - Submit in triplicate to local CAA Aviation Safety Agent. Copy will be returned to applicant upon issuance.

Supplemental Type Certificate APPLIED FOR:

**AIRCRAFT ENGINE PROPELLER**

ORIGINAL MODEL DESIGNATION Bell Model 47G NEW MODEL DESIGNATION (If desired) None Installed Franklin Model 6V-335-A engine restricted to 200 horsepower in accordence with technical data (prepared on a Form ACA-337) dated March 9, 1957.

NOTE: Aetna Helicopters Inc. Helicopter Flight Manual Supplement dated June 28, 1957 required with this installation.

4a. WILL DATA BE AVAILABLE FOR SALE OR RELEASE TO OTHER PERSONS? YES NO WILL PARTS BE MANUFACTURED FOR SALE (Ref. CAR 1.55)? YES A NO

5. SIGNATURE AND TITLE OF APPLICANT Hobort Be Primbig Lu SIGNATURE May 29, 1957 Secretary/Manage:

Date of Application: TITLE

**6. TO BE COMPLETED BY CAA**

NATURE AND LOCATION OF DATA Technical data (prepared on Form ACA-337) dated March 9, 1957, filed at Aetna Helicopters Inc. and Region 4 Aireraft Engineering Division, ORIGINAL TYPE CERTIFICATE NO. CAA APPROVAL HTC1 Supplemental Type Certificate NO.

SIGNATURE SH4-235 TE OF APPROVAL Chief, Aireraft Engineering Division June 28, 1957 TITLE COMM- DC 32484 FORM ACA-2417 (7-56)

## Every issue (1)

- June 28, 1957: Issued, Current. [certificate](https://openairdocs.org/files/sha256/f8/b7/f8b7e7e4e516472add7d57c9a9d19d29f4a88f35e510707a51e0e17cc893fb92)

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