# STC SEW-3

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: National Aircraft Sales, Inc, United States
- Description: Modification of crankshafts and reidentification according to their respective counterweight dampers.
- Status date: January 1, 1960
- Product: Engine
- Certification basis: Part 21
- Data sheets: [TCDS E-231](https://openairdocs.org/tcds/E-231), [TCDS E-264](https://openairdocs.org/tcds/E-264)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/98DDD08480C0CA4A862570D2006E7D96.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SEW-3

## ADs that name it (0)

None.

## Approved models (2)

- Pratt & Whitney Division Double Wasp CB Series ([TCDS E-264](https://openairdocs.org/tcds/E-264))
- Pratt & Whitney Division Double Wasp Series ([TCDS E-231](https://openairdocs.org/tcds/E-231))

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