# STC SA1255NW - Type: Supplemental type certificate - Status: Current, Issued - Holder: Melvin C Holten, United States - Description: Installation of a Lycoming IO-360-B1B engine, Hartzell HC-C2YK-1BF/F7666A-2 propeller and associated systems - Applied: February 17, 1979 - Status date: June 11, 1981 - Product: Aircraft, Small Airplane - Certification basis: Part 21 - Data sheets: [TCDS 1A4](https://openairdocs.org/tcds/1A4) - Certificate PDF: https://openairdocs.org/files/sha256/23/bf/23bf20978ddbd7a1ec01fd3b4622537f54a23c97fd5dbbf606b12f250bfa84fc - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/1255D374D4D1BFD886257A3A005F1753.0001 - DRS record last changed: December 5, 2025 - Page: https://openairdocs.org/stc/SA1255NW ## ADs that name it (0) None. ## Approved models (1) - Piper Aircraft Inc. PA-20-135 ([TCDS 1A4](https://openairdocs.org/tcds/1A4)) ## What the certificate says This is OCR from the scanned FAA certificate. OCR can misread letters and numbers. United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate Number: SA1255NW This certificute, ined le MELViN C. Holten Certifies that the change in the type design for the pillowing product with the limitalions and conditiona therefor us specified hereen meets the airerthiness requirments of Purt 3 ef the CiVil Ait Regulutions: Original Product - Type Bertificate Number: 194 Make: Piper Model: PA-20 "135" Description of Type Design Change: Installation of a Lycoming 10-360-BIB engine, Hartzel. HC-C2YK-1BF/F7666A-2 propeller, and associated systems in accordance with Melvin C. Holten photographs 1 through 4. Limitatmandfunditune Data pertaining to this modification are considered inadequate for duplication in other aircraft. This approval is limited to the installation in modified aircraft. United States of America Department of Transportation Federal Aviation Administration Supplemental Type Certificate (Continuation Sheet) June 11, 1981 Number: SA125515 Supplemental Type Certificate ADDENDUM NO. SA1255NW The conditions and limitations of Type Certificate Data Sheet Number 1A4 apply except where superseded by the following: Supplemental Type Certificate Data Sheet, which is part of SIC SAl255NW, prescribes the conditions and limitations under which the STC was issued meets the airworthiness requirements of the Civil Air Regulations. Supplemental Type Certificate HOLDER: Melvin C. Holten PIPER PA-20 "135", 4PCIM (NORMAL CATEGORY) AS MODIFIED BY SIC SA1255NW Engine: Lycoming I0-360-B1B Fuel: 100/130 minimum grade aviation gasoline (unuseable fuel capacity unchanged) Engine Limits: For all operations 2700 rpm (180 Hp) cropeller and Hartzell HC-C2YK-1BF/F7666A-2 Propeller Limits: Diameter: Not over 76"; Not under 74" Placard: AVOID CONTINUOUS OPERATION BETWEEN 2000 AND 2250 RPM" Pitch Settings: 11° Low; 290 High Powerplant Instrument Markings: Tachometer: 2700 rpm (red line) 2000 to 2250 rpm (red arc) Oil Temperature: 245°F (red line) Oil Pressure: 25 psi minimum (red line) 100 psi maximum (red line) 60 to 90 psi normal (green arc) Fuel Pressure: 5 psi minimum (red line) 8 psi maximum (red line) 3 to 5 psi normal (green arc) 47. **PAGE 3 OF 4 PAGES C FAA AC 73-2651** 11, 1981 STC Addendum No. SA1255NW C. G. Range: See Type Certificate Data Sheet No. 1A4 Maximum Weight: 1950 pounds Serial Number Eligible: 20-1121 NOTE 1. Current weight and balance report, together with list of equipment included in the certificated empty weight and loading instructions, when necessary, must be in the aircraft at all times. NOTE 2. The following placards must be displayed as indicated: 1. Adjacent to or in close proximity to the aircraft identification plate: **LYCOMING I0-350-B1B** **ENGINE INSTALLATION STC SA1255NW, DATE** **INSTALLED** 2. In close proximity to the tachometer: AVOID CONTINUOUS OPERATION BETWEEN 2000 AND 2250 RPM NOTE 3. With the described engine and propeller installation, performance will be at least equal to or better than that given in the original FAA Approved Flight Manual for the Piper PA-20' "135" airplane. - END - Page 4 of 4 Pages ## Every issue (1) - June 11, 1981: Issued, Current. [certificate](https://openairdocs.org/files/sha256/23/bf/23bf20978ddbd7a1ec01fd3b4622537f54a23c97fd5dbbf606b12f250bfa84fc) --- 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.