# STC SP1520SO

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Northwest Propeller Services Inc., United States
- Description: Install Memphis Prop. counterweight thrust bearings in place of the Hamilton Standard counterweight thrust bearings.
- Applied: April 7, 1983
- Status date: January 5, 1999
- Product: Propeller
- Certification basis: Part 21
- Data sheets: [TCDS P-257](https://openairdocs.org/tcds/P-257), [TCDS P-206](https://openairdocs.org/tcds/P-206)
- Certificate PDF: https://openairdocs.org/files/sha256/76/71/7671fac6e00428604e65689eb9e5b42a52f1ced7ddea8e2938a92eb1170e721e
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/7E1C8B55B7EF530486257A2C006CFC14.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SP1520SO

## ADs that name it (0)

None.

## Approved models (2)

- Hamilton Standard Division 12D40 ([TCDS P-257](https://openairdocs.org/tcds/P-257))
- Hamilton Standard Division 2D30 ([TCDS P-206](https://openairdocs.org/tcds/P-206))

## What the certificate says

The certificate is a scan without a text layer; open the PDF to read it.

## Every issue (1)

- January 5, 1999: Reissued, Current. [certificate](https://openairdocs.org/files/sha256/76/71/7671fac6e00428604e65689eb9e5b42a52f1ced7ddea8e2938a92eb1170e721e)

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