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

SA3059SW-D

Installation of Mitchell Automatic Flight System Model AK466 and AK466FD consisting of Century IV autopilot and Century IV flight director autopilot with optional annunciator. Held by Century Flight Systems INC, which holds 765 approved modifications in all. Last revised August 16, 1984. System: flight controls.

What it applies to

Kind of product
Aircraft
Design holder
Alexandria Aircraft LLC; Alexandria Aircraft LLC; Alexandria Aircraft LLC
Models
17-30A, 17-31A, 17-31ATC
Type certificates
A18CE, A18CE, A18CE
On this site
Bellanca 17 Viking 628 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.