SA3147SW-D
Installation of Mitchell Automatic Flight System Model AK603 consisting of Century I Autopilot with Optional Omni Tracker System. Held by Century Flight Systems INC, which holds 765 approved modifications in all. Last revised June 6, 1984. System: flight controls.
What it applies to
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.