The U.S. aircraft register, updated daily
Approved modifications · supplemental type certificate · current · reissued

SA7185SW-D

Installation of S-TEC System 60 two axis automatic flight guidance system, Model ST-446, with optional automatic electric trim system. Held by S-Tec Corporation, which holds 1,083 approved modifications in all. Last revised October 20, 1988. System: flight controls.

What it applies to

Kind of product
Aircraft
Design holder
Beechcraft Corporation; Beechcraft Corporation
Models
35-C33, F33C
Type certificates
3A15, 3A15
On this site
Beechcraft 35 Bonanza and Debonair 1,077 registered
Beechcraft F33 Bonanza 1,009 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.