# STC ST731SO

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: Eastern Airlines, Inc, United States
- Description: Installation of automatic in-flight lock for ventral stair-door.
- Status date: May 18, 1973
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A3WE](https://openairdocs.org/tcds/A3WE)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/A5355B601C317EC785256CC3000360E6.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/ST731SO

## ADs that name it (0)

None.

## Approved models (3)

- The Boeing Company 727 ([TCDS A3WE](https://openairdocs.org/tcds/A3WE))
- The Boeing Company 727-200 Series ([TCDS A3WE](https://openairdocs.org/tcds/A3WE))
- The Boeing Company 727C Series ([TCDS A3WE](https://openairdocs.org/tcds/A3WE))

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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.