The installation of a Pratt & Whitney PT6A-140AG engine, Avia propeller V508H/108B/A or Hartzell propeller HC-B4TN-3C/T10702N(S), fuel system and aerodynamic modifications on S2R-T34 and S2R-H80 airplanes, and installation of rudder aileron interconnect on S2R-H80 airplanes, View PDF on drs.faa.gov ↗

The STC PDF is authoritative: installation instructions, ICA requirements and limitations.