Better systems, more power and a further increase in takeoff weight were provided by Improvements beyond the Metro III. This design effort resulted in the SA227-DC model, initially called the Metro IV then renamed Metro 23, so named as it was designed for certification under FAR Part 23 standards.
The Metroliner serves as a safe and reliable passenger and cargo hauler throughout the world. Perimeter Airlines and QuikAir operate the metro on scheduled passenger service routes. Perimeter Airlines also offers corporate and air ambulance services. As a veteran operator of the Metro II, Perimeter Airlines has made many innovative changes to the design of the Metro. The airline installed Garrett engines with quieter and more efficient Hartzell propellers. The Metros are all equipped with modern avionics suites including certified KLN 90B GPS’s.