# STC SP00177SE

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: Fine Line Designs, United States
- Description: Replacement of the engine oil actuated diaphragm and servo valve system for controlling propeller pitch, with one that incorporates a separate hydraulic system utilizing hydraulic pistons.
- Status date: January 2, 2001
- Product: Propeller
- Certification basis: Part 21
- Data sheets: [TCDS P-845](https://openairdocs.org/tcds/P-845), [TCDS P46GL](https://openairdocs.org/tcds/P46GL)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FEF3044C1FB04FB285256CC2006223E3.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SP00177SE

## ADs that name it (0)

None.

## Approved models (2)

- Hartzell Propeller Inc. HC-12V ([TCDS P46GL](https://openairdocs.org/tcds/P46GL))
- Hartzell Propeller Inc. HC-12X ([TCDS P-845](https://openairdocs.org/tcds/P-845))

---
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.