# STC SA3309SO

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Challenge Air Cargo, Inc, United States
- Description: Installation of an extended time standby power system.
- Status date: September 4, 1992
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A2NM](https://openairdocs.org/tcds/A2NM)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/34E023E46CB13EE585256CC2000A96AC.0001
- DRS record last changed: December 5, 2025
- Page: https://openairdocs.org/stc/SA3309SO

## ADs that name it (0)

None.

## Approved models (1)

- The Boeing Company 757-200 ([TCDS A2NM](https://openairdocs.org/tcds/A2NM))

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