The PC-6 is a single engine, high wing, tail wheel aircraft with some characteristics that allow easy identification. First there is the straight, completely unswept vertical stabiliser. Secondly the cabin windows in the sliding doors are special. Their shape is the top half of an oval, cut in two by a frame in the middle. Behind the sliding door is a smaller round cabin window. For the rest the PC-6 is more conventional with a square cross section fuselage, strut-braced wings, a piston or turboprop engine in the nose and an all single wheel gear with tail wheel (although floats are possible as well). The main gear is attached to the front fuselage by three struts, two below the fuselage and one at the side.

While developed and mostly built in Switzerland, Fairchild acquired license production rights. Nearly a hundred were built in the United States. 

If you want to know more about the Pilatus PC-6, including productions histories and many photos, please visit pc-6.com.

The versions of the PC-6 can be distinguished from the outside by

• the shape of the nose, exhaust and cowling
• the shape of the dorsal fin
• the shape of the wingtips
• the presence of cockpit doors
  
• the nmber of pylons under the wings
  

The initial version of the PC-6 was the just designated PC-6, but is had the suffix H1 and H2 for the variants with a higher certified maximum take-off weight. These were subsequently used for all later versions as well. Later it was equipped with a more powerfull 350 hp Lycoming piston engine (hence the designation). All these piston powered versions have a long exhaust along the lower left forward fuselage, ending near the left wing strut. The PC-6/275 is supposed to have been a one-of conversion with a 275 hp engine.

PC-6/A versions all have a different Turbomeca Astazou engine, each with its own powers. This engine can be recognised by its ringshaped air intake some distance behind the propeller. It has a short, curved exhaust at the left side.

Most produced version is the PC-6/B, with a PT6A turboprop engine. It has an air intake underneath the nose, slightly aft of the prop, and exhausts on each side of the cowling. The subtypes only differ by MTOW, like explained above. The PC-6/B comes with a three or four blade propeller.

The US Army has used two examples of this version with the designation UV-20A.

Compared to the other PC-6/B subtypes this version has more rounded wingtips that end pointed instead of flat. Additionally, the PC-6/B2-H4 a larger dorsal fin than all other PC-6 versions. Finally, the cockpit doors that are optional on other versions is standard on the B2-H4.

The third engine option for the Turbo Porter was the Garrett TPE331. This has the intake underneath the prop spinner, but closer to the prop than the PC-6/B and more rounded. Also different is the large, single exhaust underneath the fuselage. This has a circular cross section and a bent halfway.

This version of the PC-6/C was only built by Fairchild, for the USAF with designation AU-23A. Many have been used in Southeast Asia during the Vietnam war. They are generally similar to the standard PC-6/C but often have two pylons under each wing to carry weapons or drop tanks. But beware: they can be removed and other PC-6 variants may have pylons under the wings (although it seems at most one on each side). Also some models may have a short exhaust at the left side of the nose.

Basically the PC-6/D is a piston powered Porter with the slightly swept, higher tail of the Pilatus PC-8. Just one was built.