# STC ST853SO

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Eastern Airlines, Inc, United States
- Description: Installation of Sundstrand ground proximity warning system.
- Status date: September 26, 1975
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 4A22](https://openairdocs.org/tcds/4A22)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/9E81A80F0B20591285256CC3000374B2.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/ST853SO

## ADs that name it (0)

None.

## Approved models (2)

- Lockheed Aircraft Corporation 188A ([TCDS 4A22](https://openairdocs.org/tcds/4A22))
- Lockheed Aircraft Corporation 188C ([TCDS 4A22](https://openairdocs.org/tcds/4A22))

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