# STC SA3257WE - Type: Supplemental type certificate - Status: Current, Reissued - Holder: Airweld Inc., United States - Description: Installation of AiResearch GTCP85-98CK auxiliary power unit in forward cargo compartment. (707-123B, -138B) - Applied: September 4, 1975 - Status date: April 28, 2008 - Product: Aircraft, Large Multi-Engine - Certification basis: Part 21 - Data sheets: [TCDS 4A21](https://openairdocs.org/tcds/4A21) - Certificate PDF: https://openairdocs.org/files/sha256/fa/cf/facf0abfae3169e4b5ed80b9c2ebaf1058c7b806b0f7a89a8e91a5a45be5c924 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/ED7D36C7726266DA86257448007776F9.0001 - DRS record last changed: December 6, 2025 - Page: https://openairdocs.org/stc/SA3257WE ## ADs that name it (0) None. ## Approved models (2) - The Boeing Company 707-100B Long Body ([TCDS 4A21](https://openairdocs.org/tcds/4A21)) - The Boeing Company 707-100B Short Body ([TCDS 4A21](https://openairdocs.org/tcds/4A21)) ## 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 BELVEDERE AVENUE, SUITE D SACRAMENTO, CALIFORNIA 95826 Part 4b of the Civil Air Regulations. dated 12/31/53; Amdts. 4b-1, 4b-2, 4b-3; Special Conditions stated in ATT. A of CAA letter dated 10/30/57; and SR422 item 2 Original Product Type Certificate Number : 4A21 Boeing 707-138B, 707-123B Description of Type Design Change: Installation of AiResearch GTCP85-CK Auxiliary Power Unit (APU) in the forward cargo compartment in accordan ce with FAA sealed World Airways Drawing List No. 491000, Revision L, or later FAA approved revisions and FAA sealed World Airways Maintenance Work Sheet E. O. No. 49-00-05 dated May 10, 1978, or later FAA approved revisions, World Ai rways, Inc., FAA approved Airplane Flight Manual Supplement No. FMS 491-1 dated August 17, 1978, or later approved revisions to Boeing Airplane Flight Manual Document D6-1585 is required as part of this installation. Limitations and Conditions: This installation is approved for ground operation only. The approval of this change in type design applies basically to the above-lis ted aircraft models 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 by the installer that the interrelationship between this change and any of those other previously approved modifications will introduce no a dverse effect upon the airworthiness of the above listed aircraft. If the holder agrees to permit another person to use this certifi cate to alter the product, the holder shall give the other person written evidence of that permission. Date of application: September 4, 1975 Date of issuance : August 27, 1976 Date reissued: November 24, 1987; July 16, 1997; January 5, 2000; December 3, 2001; April 28, 2008 Date amended : March 21, 1978; August 18, 1978 ( Signature) Manager, Propulsion Branch Los Angeles Aircraft Certification Office ( Title) Transfer the ownership of the Supplemental Type Certificate Number to (Name of transferee) (Address of transfer) (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) Extent of Authority (if licensing agreement): Signature of grantor (In ink): Number (STC No.) ## Every issue (1) - April 28, 2008: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/fa/cf/facf0abfae3169e4b5ed80b9c2ebaf1058c7b806b0f7a89a8e91a5a45be5c924) --- 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.