# STC ST121CH

- Type: Supplemental type certificate
- Status: Current, Reissued
- Holder: Gulfstream Aerospace Corporation, United States
- Description: Installation of hydraulic pump silencing kit.
- Status date: September 24, 1998
- Product: Aircraft, Large Multi-Engine
- Certification basis: Part 21
- Data sheets: [TCDS A12EA](https://openairdocs.org/tcds/A12EA)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/7E62774E2AE0AFF185256CC300035F27.0001
- DRS record last changed: December 6, 2025
- Page: https://openairdocs.org/stc/ST121CH

## ADs that name it (0)

None.

## Approved models (2)

- Gulfstream Aerospace Corporation G-1159 ([TCDS A12EA](https://openairdocs.org/tcds/A12EA))
- Gulfstream Aerospace Corporation G-1159A ([TCDS A12EA](https://openairdocs.org/tcds/A12EA))

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