# STC SA1787NM

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: Aero Air Inc, United States
- Description: Installation of two Hartzell HC-B3TN-3B/T10178B-10Q propellers on PA-31T PA-31T airplanes equipped with PWC PT6A-28 and PT6A-11 engines.
- Applied: October 12, 1982
- Status date: February 6, 1986
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A8EA](https://openairdocs.org/tcds/A8EA)
- Certificate PDF: https://openairdocs.org/files/sha256/d6/81/d6811cfbf2412d2719f6e4ec398f5f3e0e28da5b3edf28a7944f7135008ad937
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/E310D45B1BD0985185256CC10083D07F.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA1787NM

## ADs that name it (0)

None.

## Approved models (2)

- Piper Aircraft Inc. PA-31T ([TCDS A8EA](https://openairdocs.org/tcds/A8EA))
- Piper Aircraft Inc. PA-31T1 ([TCDS A8EA](https://openairdocs.org/tcds/A8EA))

## 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: SA1787NM This certificate issued to: Aero Air, Inc.

Part 3 of the Civil Air regulations.

Original Product - Type bertificate Number: ASEA Make: Piper Model:

PA-31T, PA-31T1 Description of Type Design Change: Installation of two Hartzell HC-B3TN-3B/T10178B-100 ropellers on Piper Model PA-31T and PA-31T1 airplanes equipped with Pratt and Whitne of Canada Ltd. PT6A-28 and PT6A-11 engines respectively in accordance with a FAA sealed copy of Aero Air, Inc. Installation Instructions Number AA31 dated February 6, 1986, or later FAA approved revision.

Limitations and Conditions: Approval of this change in type design applies to basic Model PA-31T and PA-31T1 airplanes only. This approval should not be extended to other airplanes of this model on which other previously approved modifications are incorporated unless it is determined by the installer that the modifications will introduce no adverse effect on the airworthiness of that aircraft. Airplanes equipped with this modification must be operated in accordance with FAA Approved Airplane Flight Manual/Pilot's Operating Handbook Supplement dated February 6, 1986, or later FAA approved

rendered, suspended, revcked, or a termination date is otherwise established by the Administrator of the Federal Aviation Administration .

Date of Application: October 12, 1982 Date Reissued:

Date of Issuance: . February 23, 1983 Date Amended: February 6, 1986 FEDERAL AVIATION By Direction of the Administrator (Signalure)

• MINISTRATO Manager, Seattle Aircraft Certification Office (Title)

47.

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate (Continuation Shect) Number SA1787NM Limitations and Conditions: (continued)

NOISE LEVEL The corrected noise level of the PA-31T is 76.4 db(a) with these propellers.

Noise testing for the PA-31T1 was not required due to similarity with the PA-31T aircraft.

No determination has been made by the Federal Aviation Administration that the noise levels of this airplane are or should be acceptable or unacceptable for operation at, into, or out of, any airport.

The above statement notwithstanding, the noise level stated above has been verified by and approved by the Federal Aviation Administration in noise level test flights conducted in accordance with FAR 36, noise standards - Aircraft Type and Airworthiness Certification. This aircraft model is in compliance with all FAR 36 noise standards applicable to this type.

- END -

47.

## Every issue (1)

- February 6, 1986: Amended, Current. [certificate](https://openairdocs.org/files/sha256/d6/81/d6811cfbf2412d2719f6e4ec398f5f3e0e28da5b3edf28a7944f7135008ad937)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.