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

SA3272SW-D

Mitchell automatic flight system AK501 consisting of Century III autopilot with optional radio and glide slope couplers. Held by Mitchell Industries, INC, which holds 31 approved modifications in all. Last revised March 10, 1978. System: flight controls.

What it applies to

Kind of product
Aircraft
Design holder
Raytheon Aircraft Company; Raytheon Aircraft Company; Raytheon Aircraft Company; Raytheon Aircraft Company
Models
S35, V35, V35A, V35B
Type certificates
3A15, 3A15, 3A15, 3A15
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 22, 2026.