# STC SA3942WE-D - Type: Supplemental type certificate - Status: Current, Reissued - Holder: United Airlines Inc, United States - Description: Rework of High-Frequency Communications System to install single-sideband capability - Applied: March 26, 1980 - Status date: November 30, 2011 - Product: Aircraft, Large Multi-Engine - Certification basis: Part 21, Part 25 - Data sheets: [TCDS A20WE](https://openairdocs.org/tcds/A20WE) - Certificate PDF: https://openairdocs.org/files/sha256/55/75/5575e3a21841c67a68a470ac26752b8bdf58abf3b217b3e52307cd0e2ca4c485 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9FA36FCDCF12C748862579980058C5B1.0001 - DRS record last changed: December 5, 2025 - Page: https://openairdocs.org/stc/SA3942WE-D ## ADs that name it (0) None. ## Approved models (1) - The Boeing Company 747-100 Series ([TCDS A20WE](https://openairdocs.org/tcds/A20WE)) ## 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 United Air Lines, Inc. 600 Jefferson Street Houston, Texas 77002 Part 25 of the Federal Aviation Regulations. A20WE Boeing 747-122 Description of Type Design Change: Rework of High-Frequency Communications System to install singlesideband capability in accordance with United Air Li nes, DAS-1-WE, Approved Drawing List No. 3942 dated March 27, 1980 or later FAA approved revisions. Limitations and Conditions: The approval of this change in type design applies only to 747-122 aircraft. This approval does not extend to other aircraft of this model on which ot her previously approved modifications are incorporated unless it is determined by the installer that the interrelationship between this change and any of those other previously a pproved modifications will introduce no adverse effect upon the airworthiness of that aircraft. This determ ination should include consideration of significant changes in weight distribution such as increase in the fixed disposable weight in the fuselage. If the holder agrees to permit another person to use this certif icate 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: March 26, 1980 Date of issuance: March 27, 1980 Date reissued: November 30, 2011 ( Signature) Haifa Haj-Eid Supervisor, Technical & Administrative Support Staff, 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.** ## Every issue (1) - November 30, 2011: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/55/75/5575e3a21841c67a68a470ac26752b8bdf58abf3b217b3e52307cd0e2ca4c485) --- 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.