# STC ST523SO

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: Aeronautical Engineers, Inc, United States
- Description: Installation of forward cargo door.
- Status date: September 24, 1973
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 6A4](https://openairdocs.org/tcds/6A4)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/65B543EA7969FE6A85256CC300036065.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/ST523SO

## ADs that name it (0)

None.

## Approved models (1)

- McDonnell Douglas Corporation DC-6B (Navy R6D-1Z) ([TCDS 6A4](https://openairdocs.org/tcds/6A4))

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