# STC SR04549AT

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Centerpointe Aerospace, United States
- Description: Conversion of the Pratt & Whitney PT6T-3 to the PT6T-3B configuration
- Applied: August 23, 2022
- Status date: February 21, 2023
- Product: Aircraft, Rotorcraft
- Certification basis: Part 29
- Data sheets: [TCDS 1H11](https://openairdocs.org/tcds/1H11)
- Certificate PDF: https://openairdocs.org/files/sha256/72/70/727012a1fcb17766ef8e4d839ecb086b634fa1d67332a5041508966a92c81f44
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID107260796920230308152008.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SR04549AT

## ADs that name it (0)

None.

## Approved models (6)

- Sikorsky Aircraft Corporation S-58BT ([TCDS 1H11](https://openairdocs.org/tcds/1H11))
- Sikorsky Aircraft Corporation S-58DT ([TCDS 1H11](https://openairdocs.org/tcds/1H11))
- Sikorsky Aircraft Corporation S-58ET ([TCDS 1H11](https://openairdocs.org/tcds/1H11))
- Sikorsky Aircraft Corporation S-58FT ([TCDS 1H11](https://openairdocs.org/tcds/1H11))
- Sikorsky Aircraft Corporation S-58HT ([TCDS 1H11](https://openairdocs.org/tcds/1H11))
- Sikorsky Aircraft Corporation S-58JT ([TCDS 1H11](https://openairdocs.org/tcds/1H11))

## 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.

United States of America Department of Transportation Federal AviationAdministration Supplemental Type Certificate Number: SR04549AT 3

This certificate issued to: Centerpointe Aerospace 279 Blackland Road Fate, Texas 75189 Part 29 of Federal Aviation Regulations .

1H11 Make: Sikorsky Model: S-58BT, S-58DT, S58-ET, S-58FT, S-58HT, Description of Type Design Change: S-58JT Conversion of the Pratt & Whitney PT6T-3 to the PT6T-3B configuration per Pratt & Whitney Canada Service Bulletin No. PT6T-72-5252, Rev. No. 3, dated Feb16, 2018 (P&WC S.B. No. 5252R3).

The installer must determine whether this design change is compatible with previously approved modifications. If the holder agrees to permit another person to use this certificate to alter a product, the holder must give the other person written evidence of that permission. Airworthiness limitations of the replacement power sections remains unchanged. (See continuation sheet 3)

Date of Application: August 23, 2022

Date Reissued: February 21, 2023

Date of Issuance: October 4, 2022 Date Amended:

(For) Christina M. Underwood, Manager, Atlanta ACO Branch

United States of America Department of Transportation Federal AviationAdministration Supplemental Type Certificate Number: SR04549AT 3

Date o transfer:

United States of America Department of Transportation Federal AviationAdministration Supplemental Type Certificate

(Continuation Sheet) Number: SR04549AT Limitations and Conditions (Cont.)

The PT6T-3B power section installed as the replacement for a PT6T-3 power section must be operated as a PT6T-3 and maintained as a PT6T-3B power section.

Replacement power sections must be operated under the lower performance/power levels of the original power sections in accordance with existing applicable Aircraft Flight Manual (AFM).

Weight and Balance Since P&W has provided the below information for all W&B changes, no additional analysis will be required. The effective CG change is minimal.

The following engine weight corrections should be made, and W&B calculations determined and logged into the AFM PT6T-3B Assembly +12.0 lbs PT6T-3B Power Section L.H. +6.0 lbs PT6T-3B Power Section R.H. +6.0 lbs

Certification Basis The certification basis is Title 14 CFR Part 29 effective February 1, 1965, including Amendments 29-1 through 29-3 and as described in TCDS 1H11, Rev. No. 19 for APECS Aerospace S-58 Series helicopters. Refer to Note 10 specifically for the introduction of the P&WC PT6T-3 Engines.

## Every issue (2)

- February 21, 2023: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/72/70/727012a1fcb17766ef8e4d839ecb086b634fa1d67332a5041508966a92c81f44)
- November 17, 2022: Issued, Historical. [certificate](https://openairdocs.org/files/sha256/cf/72/cf7249f09778b3fd51265d3c074498a99006c85f13f4bf4b9544448158de17b7)

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