Installation of vortex generators on the wings and tail surfaces and strakes on the engine nacelles.

Installation of Raisbeck/Hartzell Quiet Turbofan Propellers or Swept Blade Turbofan Propellers, and optional Increased Gross Weight

Installation of various propeller electrical de-icer models

Installation of fully enclosed main landing gear door system and associated actuation mechanism per Raisbeck Engineering Drawing List 84-1004, dated July 9, 1984, or later FAA approved revision. This modification must be maintained in accordance with Raisbeck Engineering Document No. 85-120 issued January 1990, or later FAA-accepted revision.

Installation of Electronics Int'l digital automatic engine analyzer.

Installation of modified ram air engine induction system (Option I or Option II).

Installation of American Aviation, Inc., engine exhaust stacks.

Installation of a Supplemental Exterior Lighting System in accordance with ATI Engineering Services Installation/Manufacturing Drawing List, Document No. IDL-111122, Revision 2 dated April 22, 2012, or later FAA-approved revision.

Installation of Insight Instrument Corporation Graphic Engine Monitor (GEM 610C) models G3, G2, and G1 and 1200C model G4 as primary Cylinder Head Temperature (CHT), Exhaust Gas Temperature (EGT), and Turbine Inlet Temperature (TIT) Instruments

Installation of Pratt & Whitney PT6A-27 or PT6A-28 engines.