# STC SH338NW - Type: Supplemental type certificate - Status: Current, Reissued - Holder: Siam Hiller Holdings Inc - Description: Installation of transmission oil cooling system on the Allison250-C20 turbine powered Hiller UH-12D rotorcraft. (UH-12D (ARMY UH-23D modified per STC SH177WE) - Status date: August 19, 2005 - Data sheets: 4H10 - Certificate PDF: https://openairdocs.org/files/sha256/f6/5b/f65b394d165c7b7dbbbc81245e78e81304c6c597ad8c13aebe6cb5d492775763 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/A85F31880160C763862570D90060361F.0001 - Page: https://openairdocs.org/stc/SH338NW ## ADs that name it None. ## Approved models (1) - Hiller Aviation UH-12D (Army UH-23D) (TCDS 4H10) ## 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 Siam Hiller Holdings, Inc. 925 M Street Firebaugh, California 93622 Part 27 of the Federal Aviation Regulations. 4H10 Hiller UH-12D Description of Type Design Change: Installation of a transmission oil cooling system on the Allison 250- C20 Turbine Powered Hiller UH-12D rotorcraft in accordance with Soloy Conversions, Ltd. Drawing List 560-111 dated August 4, 1976, or later FAA approved revision. The transmission oil cooler assembly must be visually inspected prior to each flight as part of the normal rotorcraft preflight inspection procedure. NOTE: Only those Hiller UH-12D rotorcraft which have been converted to turbine power in accordance with STC SH177WE are eligible for this modification. Limitations and Conditions: Approval of this change in type design applies to the above model rotorcraft only. This approval should not be extended to other rotorcraft of this model on which other previously approved modifications are incorporated unless it is determined that the interrelationship between this change and any of those other previously approved modifications will introduce no adverse effect upon the airworthiness of that rotorcraft. A copy of this Certificate must be maintained as part of the permanent records for the modified rotorcraft. 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. 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: July 22, 1976 Date of issuance: August 12, 1976 Date reissued: 06/02/83; 10/25/84; 05/28/91; 11/30/95; 08/19/05 Date amended: 05/28/91 ( Signature) Manager, Technical & Administrative Support Staff, Los Angeles Aircraft Certification Office ( Title) ## Every issue (1) - August 19, 2005: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/f6/5b/f65b394d165c7b7dbbbc81245e78e81304c6c597ad8c13aebe6cb5d492775763) --- From OpenAirDocs.org, an independent open copy of FAA data. Only the Federal Register edition on govinfo.gov is the official legal text of an AD.