# STC SA1221WE

- Type: Supplemental type certificate
- Status: Current, Amended
- Holder: American Airlines Inc, United States
- Description: Dual Collins AL-101 low range radio altimeter.
- Status date: December 29, 1966
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS 4A21](https://openairdocs.org/tcds/4A21), [TCDS 4A26](https://openairdocs.org/tcds/4A26), [TCDS 4A28](https://openairdocs.org/tcds/4A28)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D8B7E47DF445EFC685256CC10080E03E.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/SA1221WE

## ADs that name it (0)

None.

## Approved models (3)

- The Boeing Company 707 ([TCDS 4A21](https://openairdocs.org/tcds/4A21))
- The Boeing Company 707 ([TCDS 4A26](https://openairdocs.org/tcds/4A26))
- The Boeing Company 720 ([TCDS 4A28](https://openairdocs.org/tcds/4A28))

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