# STC ST866SO

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: Piedmont Aviation Inc, United States
- Description: Installation of Bendix ground proximity warning system.
- Status date: August 30, 1984
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A1PC](https://openairdocs.org/tcds/A1PC)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/BB1A3EA0BB30E33685256CC3000374B8.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/ST866SO

## ADs that name it (0)

None.

## Approved models (2)

- Mitsubishi Heavy Industries Ltd. YS-11A-500 ([TCDS A1PC](https://openairdocs.org/tcds/A1PC))
- Mitsubishi Heavy Industries Ltd. YS-11A-600 ([TCDS A1PC](https://openairdocs.org/tcds/A1PC))

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From OpenAirDocs.org, an independent open copy of FAA and NTSB data. Only the Federal Register edition on govinfo.gov is the official legal text of an AD.