STC SA1787NM

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)

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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.

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