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

SH4874SW

Install IFR Control System. Held by Associated Air Center, INC. - C/O Ct Corporation System, which holds 226 approved modifications in all. Last revised January 22, 2018. System: other and general.

What it applies to

Kind of product
Aircraft
Design holder
Bell Helicopter Textron
Models
212
Type certificate
H4SW
On this site
Bell 212 59 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 7, 2026.