# STC SA3431NM - Type: Supplemental type certificate - Status: Current, Reissued - Holder: Airweld Inc., United States - Description: Installation of a Garrett GTCP-85-98CK auxiliary power unit in the forward baggage compartment. (720-023B) - Applied: February 3, 1986 - Status date: April 28, 2008 - Product: Aircraft, Large Multi-Engine - Certification basis: Part 21 - Data sheets: [TCDS 4A28](https://openairdocs.org/tcds/4A28) - Certificate PDF: https://openairdocs.org/files/sha256/ec/f5/ecf5d3a213e5983cd6e952cf76d6255014ed0a8817aed54fb60eb29fa9e879ce - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/41D91D6B6878D0C08625744800777676.0001 - DRS record last changed: December 6, 2025 - Page: https://openairdocs.org/stc/SA3431NM ## ADs that name it (0) None. ## Approved models (1) - The Boeing Company 720 ([TCDS 4A28](https://openairdocs.org/tcds/4A28)) ## 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. This Certificate issued to AIRWELD, INC. 8167 BELEDERE AVENUE, SUITE D SACRAMENTO, CALIFORNIA 95826 Part 4B of the Civil Aviation Regulations. (See T. C. Data Sheet) Original Product Type Certificate Number : 4A28 Boeing 720-023B Description of Type Design Change: Installation of Garrett GTCP-85-98CK Auxiliary Power Unit in the forward baggage compartment in accordance with FAA approved World Airways Inc., Master Drawing List No. 497000, Revision N/C, dated September 26, 1986, or later FAA approved revision. FAA approved Airplane Flight Manual Supplement No. FMS 491-7 date d June 10, 1987, or later FAA approved revision is required. Limitations and Conditions: This installation is approved for ground operation only. The approval of this change in type design applies to the aforementioned ai rcraft model only. This modification should not be incorporated in any aircraft unless it is determined th at the interrelationship between this change and any previously approved modifications will not introduce an y adverse effect upon the airworthiness of the above listed aircraft. If the holder agrees to permit another pe rson to use this certificate to alter the product, the holder shall give the other person written evidence of that permission. This certificate and the supporting data, which is the basis for approval, shall remain in effect until surrendered, suspended, revoked or a termination date is otherwise established by the Administrator of the Federal Aviation Administration. Date of application: February 3, 1986 Date of issuance: June 16, 1987 Date reissued: November 24, 1987; July 16, 1997; January 5, 2000; December 3, 2001; April 28, 2008 ( Signature) Manager, Propulsion Branch Los Angeles Aircraft Certification Office ( Title) NOTE: **DO NOT DELETE THIS PAGE.** **DO NOT ADD ANY DATA TO THIS PAGE.** **THIS PAGE IS FOR PAGE NUMBERING PURPOSES, PLEASE DISCARD PRINTED COPY.** Number (STC No.) ## Every issue (1) - April 28, 2008: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/ec/f5/ecf5d3a213e5983cd6e952cf76d6255014ed0a8817aed54fb60eb29fa9e879ce) --- 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.