# STC SA4-31

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Mercer D W, United States
- Description: Wright R1820-52 engines and Hamilton Standard 33D50/6511-9 propellers.
- Status date: January 1, 1960
- Product: Aircraft, Small Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS ATC 540](https://openairdocs.org/tcds/ATC%20540)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D23FDAEAF6C335F086256CD8006F8924.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA4-31

## ADs that name it (0)

None.

## Approved models (1)

- Douglas Aircraft Co. Inc. DC-2 (Army C-32) ([TCDS ATC 540](https://openairdocs.org/tcds/ATC%20540))

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