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

SA2-89

Installation of Lycoming GO-480-C1D6 engines and Hartzell HC 83X20-2C/8833-2 propellers. Held by Signature Flight Support Corporation, which holds 335 approved modifications in all. Last revised August 31, 2000. System: propeller.

What it applies to

Kind of product
Aircraft
Design holder
Twin Commander Aircraft LLC
Models
560
Type certificate
6A1
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.