# STC SA4-19

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Qualitron Inc, United States
- Description: ADF antenna.
- Status date: January 1, 1960
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A-723](https://openairdocs.org/tcds/A-723)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/B36057EEF6E22C79862570CE0073081C.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA4-19

## ADs that name it (0)

None.

## Approved models (1)

- Lockheed Aircraft Corporation Lockheed 18 ([TCDS A-723](https://openairdocs.org/tcds/A-723))

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