# STC SA490GL

- Type: Supplemental type certificate
- Status: Current, Issued
- Holder: Northwest Airlines Inc, United States
- Description: Installation of a Telephonics P/N 547-000-1 central switching unit.
- Status date: January 1, 1960
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A20WE](https://openairdocs.org/tcds/A20WE)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/EA629DA26E4B8B4A862570D100554BE3.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA490GL

## ADs that name it (0)

None.

## Approved models (2)

- The Boeing Company 747-100 Series ([TCDS A20WE](https://openairdocs.org/tcds/A20WE))
- The Boeing Company 747-200B Series ([TCDS A20WE](https://openairdocs.org/tcds/A20WE))

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