# STC SA3-15 - Type: Supplemental type certificate - Status: Current, Reissued - Holder: Preferred Improvements LLC, United States - Description: Installation of wheel well enclosure doors. - Applied: December 5, 1956 - Status date: December 13, 2017 - Product: Aircraft, Large Airplane - Certification basis: Part 21 - Data sheets: [TCDS A-618](https://openairdocs.org/tcds/A-618), [TCDS A-669](https://openairdocs.org/tcds/A-669) - Certificate PDF: https://openairdocs.org/files/sha256/4b/79/4b79d031a85b8e9a3f35e5865aec239cf3eff8f1d4f58128951f0fad65d18f27 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2219117A5E94010386258210007A1D8C.0001 - DRS record last changed: December 5, 2025 - Page: https://openairdocs.org/stc/SA3-15 ## ADs that name it (0) None. ## Approved models (14) - The Boeing Company DC3-G102 ([TCDS A-618](https://openairdocs.org/tcds/A-618)) - The Boeing Company DC3-G102A ([TCDS A-618](https://openairdocs.org/tcds/A-618)) - The Boeing Company DC3-G103A ([TCDS A-618](https://openairdocs.org/tcds/A-618)) - The Boeing Company DC3-G202A ([TCDS A-618](https://openairdocs.org/tcds/A-618)) - The Boeing Company DC3A-S1C3G ([TCDS A-669](https://openairdocs.org/tcds/A-669)) - The Boeing Company DC3A-S1CG ([TCDS A-669](https://openairdocs.org/tcds/A-669)) - The Boeing Company DC3A-S4C4G ([TCDS A-669](https://openairdocs.org/tcds/A-669)) - The Boeing Company DC3A-SC3G ([TCDS A-669](https://openairdocs.org/tcds/A-669)) - The Boeing Company DC3A-SCG ([TCDS A-669](https://openairdocs.org/tcds/A-669)) - The Boeing Company DC3C-R-1830-90C ([TCDS A-669](https://openairdocs.org/tcds/A-669)) - The Boeing Company DC3C-S1C3G ([TCDS A-669](https://openairdocs.org/tcds/A-669)) - The Boeing Company DC3C-S4C4G ([TCDS A-669](https://openairdocs.org/tcds/A-669)) - The Boeing Company DC3C-SC3G ([TCDS A-669](https://openairdocs.org/tcds/A-669)) - The Boeing Company DC3D-R-1830-90C ([TCDS A-669](https://openairdocs.org/tcds/A-669)) ## 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. Preferred Improvements, LLC 11234 Hackett Road Apple Creek, OH 44606 4b Civil Air . - A-618 & A-669 Douglas DC-3 All Models Installation of Wheel Well Enclosure Doors. Data required: Remmert-Werner Drawing No’s. SK-106162-00 Rev. D, SK-10162-04 Rev. A, SK-10162-05 Rev. C, SK-10162-06, SK-10162-07, SK-10184-00 Rev. A, and SK-10184-01 Rev. A (2 sheets), or later FAA Approved revision and associated Airplane Flight Manual revision. Compatibility of this modification with other previously approved modifications must be determined by the installer. 10/1/70; 3/25/81; 6/30/83; 3/7/14; 12/5/17; 12/13/17 8/22/57; 3/14/58; 4/2/58; 3/5/59; 12/4/59; 2/24/60 Original signed by Grant Youngdahl (Signature) Grant E. Youngdahl Program Manager Wichita ACO Branch (Title) December 5, 1956 July 23, 1957 FAA FORM 8110-2-1(10-69) PAGE 2 of 3 PAGES 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): FAA FORM 8110-2-1(10-69) PAGE 3 of 3 PAGES -- SA3-15 Date Reissued: 10/1/70; 3/25/81; 3/7/14; 12/5/17; 12/13/17 Date Amended: 8/22/57; 3/14/58; 4/2/58; 3/5/59; 12/4/59; 2/24/60 (Continued from Page 1) The following Douglas DC-3 engine and gross weight combinations are approved for this modification with the appropriate CAA approved airplane: Engine T.O. **BHP M.E.T.O.** **BHP T.O.** Gross Wt. Landing Gross Wt. CAA Approved Airplane Manual Rev. Date P&W R-1830-94 1350 1100 26,200 26,000 6/25/57 P&W R-1830-94 1200 1100 26,200 26,000 6/25/57 P&W R-1830-92 1200 1050 26,200 25,200 6/25/57 P&W R-1830-92 1200 1050 26,200 26,000 4/1/57 P&W R-1830-90D 1200 1050 26,200 26,000 6/25/57 P&W R-1830-90D 1200 1050 26,200 25,200 2/24/58 P&W R-1830-94 1350 1100 26,200 25,200 12/17/57 P&W R-1830-75 1350 1100 26,200 25,200 1/10/58 P&W R-1830-75 1350 1100 26,200 26,000 1/13/58 P&W R-1830-75 1200 1050 26,200 25,200 1/8/58 W R-1820-56-AM2 1200 1100 26,200 25,200 1/14/58 W R-1820-60, -71 (G202A) 1200 1100 26,200 25,200 10/17/58 P&W R-1830-94 1200 1100 26,200 25,200 1/7/58 P&W R-1830-75 1200 1050 26,200 26,000 12/13/57 Approved March 25, 1981 --- END --- ## Every issue (2) - December 13, 2017: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/4b/79/4b79d031a85b8e9a3f35e5865aec239cf3eff8f1d4f58128951f0fad65d18f27) - March 7, 2014: Reissued, Historical. [certificate](https://openairdocs.org/files/sha256/4e/96/4e96578bdd23e16b94542b698202c3c03eea628e50543626cd0633598d55f9cb) --- 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.