# STC SA5927NM

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Helio Enterprises Inc, United States
- Description: Replace United Aircraft of Canada model PT6A-27 engine with model PT6A-34.
- Applied: January 6, 1993
- Status date: February 18, 1993
- Product: Aircraft, Single-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A4EA](https://openairdocs.org/tcds/A4EA)
- Certificate PDF: https://openairdocs.org/files/sha256/cc/31/cc31e2049021daa256ccbb98dd40667ffd9b242315c82868c39c5ba7cb3c21d0
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/AEBFCBCB45DF479A85256CC200122C85.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA5927NM

## ADs that name it (0)

None.

## Approved models (1)

- Alliance Aircraft Group LLC HST-550A (USAF AU-24A) ([TCDS A4EA](https://openairdocs.org/tcds/A4EA))

## What the certificate says

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

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number: SA5927NM This certificate issued to: Helio Enterprises, Inc.

Certifies that the change in the type design for the folowing product with the limitations and conditions thorefor as specified hereon meets the airworthiness reguirements of Purt 3 of the CiViT Air Regulations:

Original Product - Type bertificate Number: A4EA Make: Helio Model: HST - 550A Description of Type Design Change: Replace United Aircraft of Canada model PT6A-27 engine with model PT6A-34.

Limitations and Conditions: Data pertaining to this modification are considered inadequate for other aircraft. This approval is limited to the installation in Model HST-550A aircraft, Serial No. 001, R/N N550HE, only. A copy of this Certificate, Continuation Sheet and FAA Approved Flight Manual Supplement dated February 18, 1993, must be maintained as part of the permanent Records for the modified aircraft.

(Continued on page 3)

Date of Application: January 6, 1993 Jute missued:

Date of Issuance: February 18, 1993 Sate unvended:

FEDERAL AVIATION By directin of the Adm Signature ) TO MINISTRATO Seattle Aircraft Certification Office Manager, Special Certification Branch (Title) 47 FAA FoRM 8110-2 (10-68)

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate (Continuation Sheet) Number SA5927NM Limitations and Conditions: (Continued):

The conditions and limitations of the Type Certificate Data Sheet No. A4EA apply except where superseded by the following:

Engine United Aircraft of Canada PT6A-34.

REQUIRED ENGINE INSTRUMENT MARKINGS:

Inter Turbine Temperature Gauge (degrees Celsius):

green arc 0 to 695 (normal range) yellow arc 695 to 79 (cautionary range) red radial _790 (maximum; continuous, takeoff, or reverse) red radial 1090 (maximum, starting) Oil Pressure Gauge (PSIG) :

red radial 40 (minimum, gas generator speed below 27,000 rpm) yellow arc 40 to 85 (cautionary range, gas generator speed below 27,000 rpm) green arc 85 to 105 (normal range, gas generator speed 27,000 rpm or above) red radial _105 (maximum)

- END-

**FAA FORM 8110-2-1 (10-69)**

**PAGE OF PAGES C FAA AC 82-03578**

## Every issue (1)

- February 18, 1993: Issued, Current. [certificate](https://openairdocs.org/files/sha256/cc/31/cc31e2049021daa256ccbb98dd40667ffd9b242315c82868c39c5ba7cb3c21d0)

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