SA7153SW-D
Installation of S-TEC manual electric trim system, Model ST-353. Held by S-Tec Corporation, which holds 1,083 approved modifications in all. Last revised June 15, 1987. System: flight controls.
What it applies to
- Kind of product
- Aircraft
- Design holder
- SOCATA - Groupe Aerospatiale; SOCATA - Groupe Aerospatiale
- Models
- TB21, TB20
- Type certificates
- A51EU, A51EU
- On this site
- Daher (Socata) TB-20 200 registered
Daher (Socata) TB21 57 registered - The FAA's record
- On the FAA's site
What an approved modification is
A supplemental type certificate is the FAA's approval of a change to a certified design: a new engine or propeller, avionics, an autopilot, floats, a parachute, a larger fuel tank, an ice-protection kit. The company holding it may sell the kit and the paperwork to owners of the listed models; the modification then becomes part of that aircraft's record. The FAA's list says what was approved and for which models, not how many aircraft carry it.
Source: FAA supplemental type certificates (Dynamic Regulatory System). Register counts from the FAA register of October 20, 2026.