# STC SA991NW - Type: Supplemental type certificate - Status: Current, Reissued - Holder: Air Mods NW, United States - Description: Installation of model AA-5A engine mount, cowling and carburetor air box - Applied: June 19, 1980 - Status date: August 20, 2019 - Product: Aircraft, Small Airplane - Certification basis: Part 21, Part 23 - Data sheets: [TCDS A11EA](https://openairdocs.org/tcds/A11EA) - Certificate PDF: https://openairdocs.org/files/sha256/73/e5/73e50787927867d474e43a6892eed6139ff24a335b67902ed3ba533f86665dfe - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/3081CAE5D0C76301862585D80039BB56.0001 - DRS record last changed: December 5, 2025 - Page: https://openairdocs.org/stc/SA991NW ## ADs that name it (0) None. ## Approved models (4) - True Flight Holdings LLC AA-1 ([TCDS A11EA](https://openairdocs.org/tcds/A11EA)) - True Flight Holdings LLC AA-1A ([TCDS A11EA](https://openairdocs.org/tcds/A11EA)) - True Flight Holdings LLC AA-1B ([TCDS A11EA](https://openairdocs.org/tcds/A11EA)) - True Flight Holdings LLC AA-1C ([TCDS A11EA](https://openairdocs.org/tcds/A11EA)) ## 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 Aviation Administration Supplemental Type Certificate Number SA991NW This certificate, issued to Air Mods N.W. 1424 Ridge Ave Snohomish, WA 98290 Part 23 of the Federal Aviation Regulations, dated February 1, 1965, including amendments 23-1 through 23-2. Original ProductType Certificate Number: A11EA Make: Gulfstream American (Grumman) Model: AA-1, AA-1A, AA-1B, AA-1C Description of the Type Design Change: Installation of Model AA-5A engine mount, cowling, and carburetor air box in accordance with Kennis G. Blackman Installation Instructions Number KB1010. NOTE: This installation is approved on the above models with the Sensenich 72CK -S12-0-57 propeller and Lycoming 0-235-L2C(M) (modified by STC SE792NW) and Lycoming 0-235-J2A as approved in STC SA641NW. 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 this model series unless the installer determines that the relationship between this change and any other previously incorporated approved modifications will introduce no adverse effect upon the airworthiness of that aircraft. A copy of this certificate must be maintained as part of the permanent records of the modified aircraft. 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. Date of application: June 19, 1980 Date reissued: August 20, 2019 Date of issuance: July 17, 1980 Date amended: FAA FORM 8110-2 (5/14) PAGE 1 OF 2 PAGES By direction of the Administrator (Signature) Manager, Seattle ACO Branch (Title) Transfer the ownership of Supplemental Type Certificate Number to (Name of Transferee) (Address of Transferee) (Number and Street) (City, State, and ZIP Code) from (Name of Grantor) (Print or Type) (Address of Grantor) (Number and Street) (City, State, and ZIP Code) Signature of Grantor (In Ink): U.S. GPO: 1987-763-28 ## Every issue (2) - August 20, 2019: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/73/e5/73e50787927867d474e43a6892eed6139ff24a335b67902ed3ba533f86665dfe) - July 17, 1980: Issued, Historical. [certificate](https://openairdocs.org/files/sha256/a9/9b/a99b6905f2b032be0bebb6a82c5e38d1b080d144bc912eae0eb1645369545114) --- 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.