# STC SA331SO

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Montgomery Avn Corp, United States
- Description: External power supply plug.
- Status date: January 1, 1960
- Product: Aircraft, Single-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 1A15](https://openairdocs.org/tcds/1A15), [TCDS A1EA](https://openairdocs.org/tcds/A1EA)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/F48AD9374140A360862570C00077526D.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA331SO

## ADs that name it (0)

None.

## Approved models (2)

- The New Piper Aircraft Inc. PA-24 ([TCDS 1A15](https://openairdocs.org/tcds/1A15))
- The New Piper Aircraft Inc. PA-30 ([TCDS A1EA](https://openairdocs.org/tcds/A1EA))

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