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

SA00766SE

Installation of Hamilton Standard 3D40 Hub with Pacific Propeller AG-100-2 propeller blades. Held by Cascade Flying Service LLC, which holds 7 approved modifications in all. Last revised January 11, 2000. System: propeller.

What it applies to

Kind of product
Aircraft
Design holder
Air Tractor Inc.
Models
AT-401
Type certificate
A17SW
On this site
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 20, 2026.