STC SA3861NM

United States of America STe Book Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number: SA3861NM This certificate issued to: Aero Air, LLC 2050 NE 25th Avenue Hillsboro, OR 97124 Par 3 of the Civil Air Regulations.

Original Product -Type Certificate Number: 2A4 Make: Twin Commander Model: 690A, 690B, 690С Description of Type Design Change: Installation of two Hartzell HC-B3TN-SFL/LT10876ANSB-2Q propellers on the above Twin Commander airplanes equipped, with two AiResearch Model TPE331-5-254K or two Model TPE331-10T-511K, -512K, -513K, -515K, or -516K engines in accordance with a FAA sealed copy of Aero Air, Inc., Master Drawing List No. AAI-100, Revision B, dated May 23, 1999, or later FAA approved revision.

Limitations and Conditions: Approval of this change in type design applies to the above Model aircraft only.

This approval should not be extended to other aircraft of these models on which other previously approved modifications are incorporated unless it is determined that the relationship between this change and any other previously approved modifications, including changes in type design, will introduce no adverse effect upon 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 June 17, 1999, or later FAA approved revision. A copy of this Certificate, Continuation Sheet, and Airplane Flight Manual/Pilot's Operating Handbook Supplement must be maintained as part of the permanent records for the modified aircraft.

Date of Application: November 14, 1986 Date Reissued: September 25, 1998 Date of Issuance: July 29, 1987 Date Amended: 02/20/97; 09/25/98; 6/17/99 FEDERAL By Direction of the Administrator Richel & Ramet (Signature) OMINIST RATION Le Acting Manager, Seattle Aircraft Certification Office (Title)

47.

United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate (Continuation Sheet) Number: SA3861NM Aero Air, LLC Amended: 02/20/97; 09/25/98; 6/17/99 Reissued: 09/25/98 Limitations and Conditions: continued:

If the holder agrees to permit another person to use this certificate to alter the product, the holder shall give the other person written evidence of that permission.

NOISE LEVEL The noise level of this aircraft with these propellers is less than that of the original airplane.

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 relative noise level of the modified aircraft has been verified by and approved by the Federal Aviation Administration in noise level tests.

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FAA FORM 8110-2-1 (10-69) PAGE 3 OF 3 PAGES