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

SA4294SW

Installation of freon air conditioning unit (wind-driven compressor). Held by Collins Aircraft Dynamics INC, which holds 8 approved modifications in all. Last revised February 24, 2011. System: engine.

What it applies to

Kind of product
Aircraft
Design holder
Air Tractor Inc.; Air Tractor Inc.; Air Tractor Inc.; Air Tractor Inc.
Models
AT-301, AT-400A, AT-401, AT-401B
Type certificates
A9SW, A9SW, A17SW, A17SW
On this site
Air Tractor Inc AT-301 84 registered
Air Tractor Inc AT-400 49 registered
Air Tractor Inc AT-401 68 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 8, 2026.