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

SA09128AC-D

Installation of S-TEC System 40/50 single and two axis automatic flight guidance systems, Model ST-609-40/50. Held by S-Tec Corporation, which holds 1,083 approved modifications in all. Last revised May 28, 1998. System: other and general.

What it applies to

Kind of product
Aircraft
Design holder
Maule Aerospace Technology Inc.; Maule Aerospace Technology Inc.
Models
MT-7-235, MX-7-180C
Type certificates
3A23, 3A23
On this site
Maule MT-7 76 registered
Maule MX-7 192 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.